add rng, rtc, networking, more CSR paravirt exts and fixes

honestly forgot what I added all over the last year or so, but here you
go, enjoy more cursed code

.gitignore

@@ -1,5 +1,6 @@
 compile_commands.json
 .ccls-cache
+.cache
 elfy/.ccls-cache
 rvc
 !rvc/

Makefile

@@ -3,6 +3,8 @@ SRC_DIRS ?= ./src ./tinypngout
 
 CC=clang
 
+BUILDROOT := "buildroot-2022.02.1"
+
 SRCS := $(shell find $(SRC_DIRS) -name '*.cpp' -or -name '*.c' -or -name '*.s')
 OBJS := $(addsuffix .o,$(basename $(SRCS)))
 DEPS := $(OBJS:.o=.d)
@@ -10,12 +12,18 @@ DEPS := $(OBJS:.o=.d)
 INC_DIRS := $(shell find $(SRC_DIRS) -type d)
 INC_FLAGS := $(addprefix -I,$(INC_DIRS))
 
-Q=$(CURDIR)/buildroot-2021.05/output/host/bin/riscv32-buildroot-linux-gnu-
+Q=$(CURDIR)/$(BUILDROOT)/output/host/bin/riscv32-buildroot-linux-gnu-
 
 CFLAGS ?= -g -O2
 
-$(TARGET): $(OBJS)
+.PHONY: $(TARGET)
-	$(CC) $(LDFLAGS) -I./elfy/elfy.h -I./tinypngout/TinyPngOut.h $(OBJS) -o $@ $(LOADLIBES) $(LDLIBS) -L./elfy/target/release/ -Wl,--no-as-needed -ldl -lpthread -lelfy
+$(TARGET):
+	touch src/main.c
+	rm -f src/main.o
+	$(MAKE) $(TARGET)-real
+
+$(TARGET)-real: $(OBJS)
+	$(CC) $(LDFLAGS) -I./elfy/elfy.h -I./tinypngout/TinyPngOut.h $(OBJS) -o $(TARGET) $(LOADLIBES) $(LDLIBS) -L./elfy/target/release/ -Wl,--no-as-needed -ldl -lpthread -lelfy -lm
 
 -include $(DEPS)
 
@@ -28,11 +36,9 @@ PAYLOAD=rust_payload/target/riscv32ima-unknown-none-elf/release/rust_payload.bin
 LINUX_PAYLOAD=linux/arch/riscv/boot/Image
 RAYTRACE_PAYLOAD=rust_raytrace/target/riscv32ima-unknown-none-elf/release/rust_raytrace.bin
 
-BUILDROOT_MARKER=buildroot-2021.05/build.marker
+BUILDROOT_MARKER=$(BUILDROOT)/build.marker
 $(BUILDROOT_MARKER):
-	$(MAKE) -C buildroot-2021.05
+	if [ ! -f $(BUILDROOT_MARKER) ]; then $(MAKE) -C $(BUILDROOT); fi
-	cd buildroot-2021.05 && cp init output/target/ && cp pi.js output/target/
-	$(MAKE) -C buildroot-2021.05
 	touch $@
 
 $(PAYLOAD): $(shell find rust_payload/src -type f)
@@ -66,7 +72,7 @@ rust_payload.elf: $(PAYLOAD) $(BUILDROOT_MARKER)
 
 .PHONY: $(LINUX_PAYLOAD)
 $(LINUX_PAYLOAD): linux $(BUILDROOT_MARKER)
-	cd linux && (git am ../linux-_pi_-patches-for-rvc.patch || true)
+	# cd linux && (git apply ../linux-_pi_-patches-for-rvc.patch || true)
 	cd linux && \
 		env CROSS_COMPILE=$(Q) \
 			CFLAGS="-march=rv32ima -mabi=ilp32" \
@@ -74,12 +80,14 @@ $(LINUX_PAYLOAD): linux $(BUILDROOT_MARKER)
 			ARCH=riscv \
 			KCONFIG_ALLCONFIG=../linux.config \
 				make allnoconfig
+	cd linux && ./scripts/clang-tools/gen_compile_commands.py
 	cd linux && \
 		env CROSS_COMPILE=$(Q) \
 			CFLAGS="-march=rv32ima -mabi=ilp32" \
 			LDFLAGS="-march=rv32ima -mabi=ilp32" \
 			ARCH=riscv \
-				intercept-build make -j$(shell nproc)
+				make -j$(shell nproc)
+	cd linux && ./scripts/clang-tools/gen_compile_commands.py
 
 linux_payload.bin: linux_payload.elf
 	cp $(OPENSBI_BUILD)/fw_payload.bin ./linux_payload.bin
@@ -99,9 +107,17 @@ linux_payload.elf: $(LINUX_PAYLOAD) $(BUILDROOT_MARKER)
 run: fw_payload.bin $(TARGET) dts.dtb
 	./rvc -b fw_payload.bin -d dts.dtb
 
+.PHONY: run-v1
 run-v1: fw_payload.bin $(TARGET) dts.dtb
 	./rvc -b fw_payload.bin -d dts.dtb -v1
 
+.PHONY: run-network
+run-network: linux_payload.bin $(TARGET) dts.dtb
+	tmux new -s rvc-network -d "./rvc -b linux_payload.bin -d dts.dtb -n /tmp/rvc-test.sock -i ./$(BUILDROOT)/output/images/rootfs.romfs -f"
+	tmux split-window -t rvc-network "./rvc -b linux_payload.bin -d dts.dtb -N /tmp/rvc-test.sock -i ./$(BUILDROOT)/output/images/rootfs.romfs -f"
+	tmux select-layout -t rvc-network even-horizontal
+	tmux attach -t rvc-network
+	tmux kill-session -t rvc-network || true
 
 .PHONY: clean
 clean:

bare_metal_test/Makefile

@@ -5,7 +5,7 @@ PREFIX ?= ../buildroot-2021.05/output/host/bin/riscv32-buildroot-linux-gnu-
 CC := $(PREFIX)cc
 AS := $(PREFIX)as
 LD := $(PREFIX)ld
-OBJDUMP := $(PREFIX)objcopy
+OBJCOPY := $(PREFIX)objcopy
 
 SRCS := $(wildcard *.S)
 SRCS += $(wildcard *.c)
@@ -23,7 +23,7 @@ $(TARGET): $(OBJS)
 	$(CC) $(LDFLAGS) $(OBJS) -o $@ $(LOADLIBES) $(LDLIBS)
 
 $(TARGET).img: $(TARGET)
-	riscv32-elf-objcopy -O binary $< $@
+	$(OBJCOPY) -O binary $< $@
 
 .PHONY: clean
 clean:

bare_metal_test/bare.c

@@ -101,6 +101,20 @@ int main(void) {
         print("\n");
     }
 
+    print("[bare] testing memory writeback...\n");
+    volatile unsigned int *ptr = (unsigned int*)0x80010000;
+    *ptr = 0xccddeeff;
+    __asm volatile("fence.i");
+    unsigned int readback = *ptr;
+    if (readback != 0xccddeeff) {
+        print("[bare/writeback] test failed! expected=0xccddeeff got=0x");
+        print_hex(readback);
+        print("\n");
+        __asm volatile ("ebreak");
+        while (true) {}
+    }
+    print("[bare/writeback] success!\n");
+
     print("[bare] testing trap handler...\n");
     __asm volatile("csrw sip, 0x2");
 

bare_metal_test/riscv32.ld

@@ -1,6 +1,6 @@
 MEMORY
 {
-    RAM : ORIGIN = 0x80000000, LENGTH = 31M
+    RAM : ORIGIN = 0x80000000, LENGTH = 60M
 }
 
 _estack = ORIGIN(RAM) + LENGTH(RAM);

dts.dts

@@ -6,23 +6,38 @@
     compatible = "riscv-virtio";
     model = "generic,rvc";
 
-    chosen {
+    aliases {
-        bootargs = "console=hvc0 earlycon=sbi loglevel=15 debug single";
+        serial0 = &uart0;
-        //stdout-path = "/uart@10000000";
     };
 
-    uart@10000000 {
+    chosen {
-        interrupts = <0x1>;
+        bootargs = "root=mtd:root rootfstype=romfs ro init=/rvcinit phram.phram=root,0x40000000,256Mi console=hvc0 earlycon=sbi";
-        interrupt-parent = <&irqchip>;
+        stdout-path = "/uart@10000000";
+    };
+
+    uart0: uart@10000000 {
+        /* interrupts = <0x9>; */
+        /* interrupt-parent = <&irqchip>; */
         clock-frequency = <0x384000>;
         reg = <0x0 0x10000000 0x0 0x100>;
         compatible = "ns16550a";
     };
 
+    rtc@3000000 {
+        compatible = "maxim,ds1742";
+        reg = <0x0 0x3000000 0x0 0x800>;
+    };
+
+    rvcnet {
+        compatible = "pi,rvcnet";
+    };
+
     cpus {
         #address-cells = <0x1>;
         #size-cells = <0x0>;
-        timebase-frequency = <0x1000000>;
+
+        /* 100/20 kHz, must match frequency in emu.h */
+        timebase-frequency = <0x1388>;
 
         cpu-map {
             cluster0 {
@@ -51,7 +66,7 @@
 
     memory@80000000 {
         device_type = "memory";
-        reg = <0x0 0x80000000 0x0 0x03B00000>; /* includes safety margin at end? */
+        reg = <0x0 0x80000000 0x0 0x07B00000>; /* includes safety margin at end? */
     };
 
     soc {

guest-root/examples/pi.js

@@ -0,0 +1,119 @@
+/*
+ * PI computation in Javascript using the BigInt type
+ * from: https://bellard.org/quickjs/pi.html
+ */
+"use strict";
+
+/* return floor(log2(a)) for a > 0 and 0 for a = 0 */
+function floor_log2(a)
+{
+    var k_max, a1, k, i;
+    k_max = 0n;
+    while ((a >> (2n ** k_max)) != 0n) {
+        k_max++;
+    }
+    k = 0n;
+    a1 = a;
+    for(i = k_max - 1n; i >= 0n; i--) {
+        a1 = a >> (2n ** i);
+        if (a1 != 0n) {
+            a = a1;
+            k |= (1n << i);
+        }
+    }
+    return k;
+}
+
+/* return ceil(log2(a)) for a > 0 */
+function ceil_log2(a)
+{
+    return floor_log2(a - 1n) + 1n;
+}
+
+/* return floor(sqrt(a)) (not efficient but simple) */
+function int_sqrt(a)
+{
+    var l, u, s;
+    if (a == 0n)
+        return a;
+    l = ceil_log2(a);
+    u = 1n << ((l + 1n) / 2n);
+    /* u >= floor(sqrt(a)) */
+    for(;;) {
+        s = u;
+        u = ((a / s) + s) / 2n;
+        if (u >= s)
+            break;
+    }
+    return s;
+}
+
+/* return pi * 2**prec */
+function calc_pi(prec) {
+    const CHUD_A = 13591409n;
+    const CHUD_B = 545140134n;
+    const CHUD_C = 640320n;
+    const CHUD_C3 = 10939058860032000n; /* C^3/24 */
+    const CHUD_BITS_PER_TERM = 47.11041313821584202247; /* log2(C/12)*3 */
+
+    /* return [P, Q, G] */
+    function chud_bs(a, b, need_G) {
+        var c, P, Q, G, P1, Q1, G1, P2, Q2, G2;
+        if (a == (b - 1n)) {
+            G = (2n * b - 1n) * (6n * b - 1n) * (6n * b - 5n);
+            P = G * (CHUD_B * b + CHUD_A);
+            if (b & 1n)
+                P = -P;
+            Q = b * b * b * CHUD_C3;
+        } else {
+            c = (a + b) >> 1n;
+            [P1, Q1, G1] = chud_bs(a, c, true);
+            [P2, Q2, G2] = chud_bs(c, b, need_G);
+            P = P1 * Q2 + P2 * G1;
+            Q = Q1 * Q2;
+            if (need_G)
+                G = G1 * G2;
+            else
+                G = 0n;
+        }
+        return [P, Q, G];
+    }
+
+    var n, P, Q, G;
+    /* number of serie terms */
+    n = BigInt(Math.ceil(Number(prec) / CHUD_BITS_PER_TERM)) + 10n;
+    [P, Q, G] = chud_bs(0n, n, false);
+    Q = (CHUD_C / 12n) * (Q << prec) / (P + Q * CHUD_A);
+    G = int_sqrt(CHUD_C << (2n * prec));
+    return (Q * G) >> prec;
+}
+
+function main(args) {
+    var r, n_digits, n_bits, out;
+    if (args.length < 1) {
+        print("usage: pi n_digits");
+        return;
+    }
+    n_digits = args[0] | 0;
+
+    /* we add more bits to reduce the probability of bad rounding for
+      the last digits */
+    n_bits = BigInt(Math.ceil(n_digits * Math.log2(10))) + 32n;
+    r = calc_pi(n_bits);
+    r = ((10n ** BigInt(n_digits)) * r) >> n_bits;
+    out = r.toString();
+    print(out[0] + "." + out.slice(1));
+}
+
+var args;
+if (typeof scriptArgs != "undefined") {
+    args = scriptArgs;
+    args.shift();
+} else if (typeof arguments != "undefined") {
+    args = arguments;
+} else {
+    /* default: 1000 digits */
+    args=[1000];
+}
+
+main(args);

guest-root/install.sh

@@ -0,0 +1,39 @@
+#!/bin/sh
+
+BUILDROOT="buildroot-2022.02.1"
+
+set -e
+
+# target directory
+Q=$1
+
+# enter current directory
+cd ../guest-root
+
+for f in *; do
+    if [ "$f" == "install.sh" ]; then continue; fi
+    cp -r -v "$f" "$Q"
+done
+
+mkdir -p "$Q/tmp/work"
+mkdir -p "$Q/tmp/upper"
+mkdir -p "$Q/tmp/newroot"
+
+# install beluga
+cd ../riscv32_beluga
+sed -i 's|$(CC) -o $S/ecgen|$(HOSTCC) -o $S/ecgen|' bcc/Makefile
+make clean
+make -j1 CC=$PWD/../$BUILDROOT/output/host/bin/riscv32-buildroot-linux-gnu-gcc HOSTCC=gcc
+cd ..
+mkdir -p $BUILDROOT/output/target/usr/local/bin
+cp riscv32_beluga/build/{bcc,beluga} $BUILDROOT/output/target/usr/local/bin
+# ln -s libc.so.6 $(BUILDROOT)/output/target/lib32/libc.so || true
+# ln -s libm.so.6 $(BUILDROOT)/output/target/lib32/libm.so || true
+# cp riscv32_beluga/riscvbin/bin/{as,ld,ar,dof} $(BUILDROOT)/output/target/usr/local/bin
+mkdir -p $BUILDROOT/output/target/usr/local/lib32/bcc
+cp riscv32_beluga/build/xfloat.o $BUILDROOT/output/target/usr/local/lib32/bcc/
+cp -Lr riscv32_beluga/build/include $BUILDROOT/output/target/usr/local/lib32/bcc/
+cp riscv32_beluga/riscvbin/ar/libc.a $BUILDROOT/output/target/usr/local/lib32/
+cp $BUILDROOT/output/host/lib/gcc/riscv32-buildroot-linux-gnu/11.2.0/libgcc.a $BUILDROOT/output/target/usr/local/lib32/
+cp $BUILDROOT/output/host/lib/gcc/riscv32-buildroot-linux-gnu/11.2.0/libgcc_eh.a $BUILDROOT/output/target/usr/local/lib32/
+

guest-root/network-setup.sh

@@ -0,0 +1,18 @@
+#!/bin/sh
+
+echo "Configuring network..."
+
+# Start loopback interface, it will auto-assign 127.0.0.1/8 as IP
+ip link set up lo
+
+PLID=$(cat /sys/kernel/rvc/player_id)
+echo "Player ID: $PLID"
+PLID=$(( (PLID + 1) % 255 ))
+echo "Network ID: $PLID"
+
+# Configure rvcnet for external networking
+ip link set dev rvcnet up
+ip addr add "10.0.0.$PLID/24" dev rvcnet
+
+echo "Network state:"
+ip addr show

guest-root/rvcinit

@@ -0,0 +1,44 @@
+#!/bin/sh
+
+if [ "$1" != "chroot" ]; then
+    echo
+    echo "> Welcome to userland!"
+    echo "> Setting up overlay mount for writeable root"
+    mount -t tmpfs tmpfs /tmp
+    mkdir /tmp/upper
+    mkdir /tmp/work
+    mkdir /tmp/newroot
+    mount -t overlay overlay \
+        -o lowerdir=/,upperdir=/tmp/upper,workdir=/tmp/work /tmp/newroot
+    mount --bind /dev /tmp/newroot/dev
+    chroot /tmp/newroot /rvcinit chroot
+else
+    echo "> Entered overlay chroot, mounting /proc & /sys"
+    mount -t proc proc /proc
+    mount -t sysfs sys /sys
+
+    echo "> Startup took: $(cut -d' ' -f0 </proc/uptime)s"
+
+cat << EOF
+                  _ _
+                 | (_)
+ _ ____   _____  | |_ _ __  _   ___  __
+| '__\ \ / / __| | | | '_ \| | | \ \/ /
+| |   \ V / (__  | | | | | | |_| |>  <
+|_|    \_/ \___| |_|_|_| |_|\__,_/_/\_\ 
+
+
+                              by _pi_
+
+EOF
+
+    echo "> Starting login shell on TTY /dev/hvc0"
+
+    export PATH="$PATH:/usr/local/bin"
+
+    while true; do
+        # use getty to start a shell in a new tty
+        getty -l /bin/sh -n 0 /dev/hvc0
+        echo "> Restarting login shell"
+    done
+fi

linux

@@ -1 +1 @@
-Subproject commit f4e0f631965ce23bca273bdcc7c1637bc9993365
+Subproject commit 0bd94b14f8b6b838bbd48e5c204e819df621e659

linux-_pi_-patches-for-rvc.patch

@@ -1,129 +0,0 @@
-From 30022eebb78abc5a8a9289aecbd30a155fafcff0 Mon Sep 17 00:00:00 2001
-From: Stefan <stefan@pimaker.at>
-Date: Sun, 1 Aug 2021 20:58:20 +0200
-Subject: [PATCH] _pi_ patches for rvc
-
-* use MEMOP extension for faster memcpy
-* don't poison init kernel area, we don't care about security
-* print more messages about initramfs loading, since otherwise it just
-  looks like it got stuck
-
-Signed-off-by: Stefan <stefan@pimaker.at>
----
- arch/riscv/lib/memcpy.S | 14 ++++++++++++++
- include/linux/mm.h      |  2 +-
- init/initramfs.c        | 19 +++++++++++++++++--
- 3 files changed, 32 insertions(+), 3 deletions(-)
-
-diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
-index 51ab716253fa..67e3cf24d9d0 100644
---- a/arch/riscv/lib/memcpy.S
-+++ b/arch/riscv/lib/memcpy.S
-@@ -41,6 +41,19 @@ WEAK(memcpy)
- 	beqz a4, 4f
- 	add a3, a1, a4
- 3:
-+	# fast memcpy for page-sized chunks
-+	lla t0, 10f
-+	li t2, 4096
-+	bne a2, t2, 11f
-+
-+	csrw 0x0b1, a1 # src
-+	csrw 0x0b2, t6 # dst
-+	csrw 0x0b3, a2 # n
-+	li t2, 0x1
-+	csrw 0x0b0, t2 # memcpy
-+	j 10f
-+
-+11:
- 	REG_L a4,       0(a1)
- 	REG_L a5,   SZREG(a1)
- 	REG_L a6, 2*SZREG(a1)
-@@ -76,6 +89,7 @@ WEAK(memcpy)
- 	REG_S t1, 15*SZREG(t6)
- 	addi t6, t6, 16*SZREG
- 	bltu a1, a3, 3b
-+10:
- 	andi a2, a2, (16*SZREG)-1  /* Update count */
- 
- 4:
-diff --git a/include/linux/mm.h b/include/linux/mm.h
-index 9afb8998e7e5..881f1c1cf7ea 100644
---- a/include/linux/mm.h
-+++ b/include/linux/mm.h
-@@ -2420,7 +2420,7 @@ static inline unsigned long free_initmem_default(int poison)
- 	extern char __init_begin[], __init_end[];
- 
- 	return free_reserved_area(&__init_begin, &__init_end,
--				  poison, "unused kernel");
-+				  0x1ff, "unused kernel");
- }
- 
- static inline unsigned long get_num_physpages(void)
-diff --git a/init/initramfs.c b/init/initramfs.c
-index af27abc59643..1124f0cf6c8f 100644
---- a/init/initramfs.c
-+++ b/init/initramfs.c
-@@ -43,8 +43,10 @@ static ssize_t __init xwrite(struct file *file, const char *p, size_t count,
- static __initdata char *message;
- static void __init error(char *x)
- {
--	if (!message)
-+	if (!message) {
- 		message = x;
-+		pr_err("[_pi_] initramfs error: %s\n", x);
-+	}
- }
- 
- static void panic_show_mem(const char *fmt, ...)
-@@ -467,6 +469,9 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
- 	const char *compress_name;
- 	static __initdata char msg_buf[64];
- 
-+	unsigned long len_orig = len;
-+	unsigned long len_percent = 0, len_percent_tmp;
-+
- 	header_buf = kmalloc(110, GFP_KERNEL);
- 	symlink_buf = kmalloc(PATH_MAX + N_ALIGN(PATH_MAX) + 1, GFP_KERNEL);
- 	name_buf = kmalloc(N_ALIGN(PATH_MAX), GFP_KERNEL);
-@@ -474,11 +479,20 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
- 	if (!header_buf || !symlink_buf || !name_buf)
- 		panic_show_mem("can't allocate buffers");
- 
-+	pr_info("[_pi_] loading initramfs now, this may take a while...\n");
-+
- 	state = Start;
- 	this_header = 0;
- 	message = NULL;
- 	while (!message && len) {
- 		loff_t saved_offset = this_header;
-+
-+		len_percent_tmp = (len * 10) / len_orig;
-+		if (len_percent_tmp != len_percent) {
-+			len_percent = len_percent_tmp;
-+			pr_info("[_pi_] initramfs: %lu0%% done\n", 10 - len_percent);
-+		}
-+
- 		if (*buf == '0' && !(this_header & 3)) {
- 			state = Start;
- 			written = write_buffer(buf, len);
-@@ -494,7 +508,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
- 		}
- 		this_header = 0;
- 		decompress = decompress_method(buf, len, &compress_name);
--		pr_debug("Detected %s compressed data\n", compress_name);
-+		pr_info("Detected %s compressed data\n", compress_name);
- 		if (decompress) {
- 			int res = decompress(buf, len, NULL, flush_buffer, NULL,
- 				   &my_inptr, error);
-@@ -519,6 +533,7 @@ static char * __init unpack_to_rootfs(char *buf, unsigned long len)
- 	kfree(name_buf);
- 	kfree(symlink_buf);
- 	kfree(header_buf);
-+	pr_info("[_pi_] unpack_to_rootfs retval: %s\n", (message && *message) ? message : "<success>");
- 	return message;
- }
- 
--- 
-2.32.0
-

linux.config

@@ -17,10 +17,11 @@ CONFIG_INITRAMFS_COMPRESSION_LZ4=n
 CONFIG_INITRAMFS_COMPRESSION_ZSTD=n
 CONFIG_INITRAMFS_COMPRESSION_NONE=y
 
-CONFIG_INITRAMFS_SOURCE="../buildroot-2021.05/output/images/rootfs.cpio"
+# CONFIG_INITRAMFS_SOURCE="../buildroot-2021.05/output/images/rootfs.cpio"
 
-CONFIG_BLK_DEV=y
+CONFIG_BLOCK=n
-CONFIG_BLK_DEV_INITRD=y
+CONFIG_BLK_DEV=n
+CONFIG_BLK_DEV_INITRD=n
 
 CONFIG_DEBUG=y
 CONFIG_DEBUG_KERNEL=y
@@ -57,18 +58,22 @@ CONFIG_TTY=y
 CONFIG_VT=y
 CONFIG_VT_CONSOLE=y
 CONFIG_VT_HW_CONSOLE_BINDING=y
-CONFIG_SERIAL_CORE=y
+CONFIG_SERIAL_CORE=n
-CONFIG_SERIAL_CORE_CONSOLE=y
+CONFIG_SERIAL_CORE_CONSOLE=n
 CONFIG_SERIAL_8250=n
 CONFIG_SERIAL_8250_CONSOLE=n
-CONFIG_SERIAL_OF_PLATFORM=y
+CONFIG_SERIAL_8250_16550A_VARIANTS=n
-CONFIG_SERIAL_EARLYCON=y
+CONFIG_SERIAL_EARLYCON=n
 CONFIG_CONSOLE_POLL=n
 CONFIG_UNIX98_PTYS=n
 CONFIG_LEGACY_PTYS=n
 
 CONFIG_RISCV_TIMER=y
 CONFIG_PREEMPT_NONE=y
+CONFIG_NO_HZ=y
+CONFIG_NO_HZ_IDLE=y
+CONFIG_HZ_20=y
+CONFIG_HZ=20
 
 CONFIG_DTC=y
 CONFIG_OF=y
@@ -78,6 +83,11 @@ CONFIG_OF_KOBJ=y
 CONFIG_OF_ADDRESS=y
 CONFIG_OF_IRQ=y
 CONFIG_OF_RESERVED_MEM=y
+CONFIG_OF_SERIAL=y
+CONFIG_SERIAL_OF_PLATFORM=y
+
+CONFIG_MTD=y
+CONFIG_MTD_PHRAM=y
 
 CONFIG_RAMFS=y
 CONFIG_TMPFS=y
@@ -85,19 +95,20 @@ CONFIG_DEVTMPFS=y
 CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_PROC_FS=y
 CONFIG_SYSFS=y
-CONFIG_EXPORTFS=n
+
+CONFIG_MISC_FILESYSTEMS=y
+CONFIG_ROMFS_FS=y
+CONFIG_ROMFS_BACKED_BY_MTD=y
+CONFIG_ROMFS_BACKED_BY_BLOCK=n
+CONFIG_OVERLAY_FS=y
 
 CONFIG_MSDOS_PARTITION=n
 CONFIG_EFI_PARTITION=n
 CONFIG_FW_LOADER=n
 CONFIG_SCSI_MOD=n
-CONFIG_BLK_DEV_BSG=n
 CONFIG_MQ_IOSCHED_KYBER=n
 CONFIG_MQ_IOSCHED_DEADLINE=n
 CONFIG_IO_WQ=n
-CONFIG_SERIAL_8250_16550A_VARIANTS=n
-CONFIG_SERIAL_8250_NR_UARTS=1
-CONFIG_SERIAL_8250_RUNTIME_UARTS=1
 CONFIG_VGA_CONSOLE=n
 CONFIG_HID=n
 CONFIG_USB_SUPPORT=n
@@ -112,3 +123,17 @@ CONFIG_USB=n
 CONFIG_HAVE_SYSCALL_TRACEPOINTS=n
 CONFIG_TRACING_SUPPORT=n
 CONFIG_FTRACE=n
+
+CONFIG_NET=y
+CONFIG_NET_CORE=y
+CONFIG_NETDEVICES=y
+CONFIG_PACKET=y
+CONFIG_NETLINK_DIAG=y
+CONFIG_UNIX=y
+CONFIG_INET=y
+CONFIG_RVCNET=y
+
+CONFIG_RTC_LIB=y
+CONFIG_RTC_CLASS=y
+CONFIG_RTC_HCTOSYS=y
+CONFIG_RTC_DRV_DS1742=y

riscv-rust

@@ -1 +1 @@
-Subproject commit b4895fc56b16815d622b088d188ac65d640d25ab
+Subproject commit 8ee69d7a5dc7ef6d8b2bda96bf86d2923f2cf176

rust_raytrace/linker.ld

@@ -4,7 +4,7 @@ ENTRY( _start )
 
 MEMORY
 {
-  ram (rwx) : ORIGIN = 0x80000000, LENGTH = 0x80000
+  ram (rwx) : ORIGIN = 0x80000000, LENGTH = 0x100000
 }
 
 SECTIONS
@@ -17,14 +17,18 @@ SECTIONS
   } > ram
 
   .stack (NOLOAD) : {
-    . = . + 0x20000;
+    . = . + 0x70000;
     PROVIDE(_end_stack = .);
   } > ram
 
   .heap (NOLOAD) : {
-    PROVIDE(_begin_heap = .);
+    . = . + 0x70000;
-    . = . + 0x40000;
     PROVIDE(_end_heap = .);
   } > ram
 
+  .textbuf (NOLOAD) : {
+    . = . + 0x10000;
+    PROVIDE(_end_textbuf = .);
+  } > ram
+
 }

rust_raytrace/src/fb.rs

@@ -0,0 +1,36 @@
+use super::math::Color;
+
+const RAM_BASE: u32 = 0x80000000;
+const FB_START: u32 = 0x80000;
+pub const FB_WIDTH: u32 = 2048;
+pub const FB_HEIGHT: u32 = 2048 - 32 /* progmem */ - 128 /* CPU state */;
+pub const FB_HEIGHT_SLICE: u32 = 224; // FB_HEIGHT / 8
+
+#[inline(always)]
+/// accelerated "big" pixel drawing, superscale is size of pixel, forces stall
+pub unsafe fn write_px_memop(x: u32, y: u32, col: Color, superscale: u32) {
+    let bits: u32 = col.r * 0xffffff;
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b3); // CSR_MEMOP_R
+    let bits: u32 = col.g * 0xffffff;
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b4); // CSR_MEMOP_G
+    let bits: u32 = col.b * 0xffffff;
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b5); // CSR_MEMOP_B
+
+    let bits: u32 = x | (y << 16);
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b1); // CSR_MEMOP_SRC
+    let bits: u32 = (x + superscale) | ((y + superscale) << 16);
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b2); // CSR_MEMOP_DST
+
+    let bits: u32 = 1;
+    asm!("csrrw x0, {1}, {0}", in(reg) bits, const 0x0b0); // CSR_MEMOP_OP
+}
+
+#[inline(always)]
+/// write a single pixel, unaccelerated, uses main memory but doesn't stall
+pub fn write_px_raw(x: u32, y: u32, col: u128) {
+    unsafe {
+        let ptr = (FB_START + RAM_BASE) as *mut u128;
+        let ptr = ptr.add((x + y * FB_WIDTH) as usize);
+        ptr.write(col);
+    }
+}

rust_raytrace/src/low_level/mod.rs

@@ -1,8 +1,8 @@
 use core::panic::PanicInfo;
 use linked_list_allocator::LockedHeap;
+use super::output::*;
 
-mod uart;
+pub mod uart;
-pub use uart::*;
 
 #[naked]
 #[no_mangle]
@@ -13,7 +13,11 @@ extern "C" fn _start() -> ! {
     unsafe {
         asm!(
             "
+                csrr t0, 0xf14
                 la sp, {end_stack}
+                li t2, 4096
+                mul t1, t0, t2
+                sub sp, sp, t1
                 j main
             ",
             end_stack = sym _end_stack,
@@ -31,6 +35,7 @@ fn alloc_error(_layout: core::alloc::Layout) -> ! {
 #[panic_handler]
 fn panic(_info: &PanicInfo) -> ! {
     println("PANIC!");
+    unsafe { asm! { "ebreak" } }
     loop {}
 }
 
@@ -41,22 +46,31 @@ extern "C" {
     static _end_heap: usize;
 }
 
+// not actually safe between harts, but shouldn't be used so ignore?
 #[global_allocator]
 static ALLOCATOR: LockedHeap = LockedHeap::empty();
 
+#[inline(always)]
+pub fn hartid() -> usize {
+    let hartid: usize;
+    unsafe { asm!("csrrs {0}, {1}, x0", out(reg) hartid, const 0xf14); }
+    return hartid;
+}
+
 pub unsafe fn init_heap() {
     let stack_end = &_end_stack as *const usize as usize;
-    let heap_start = &_begin_heap as *const usize as usize;
+    let heap_start = stack_end + hartid() * 4096;
     let heap_end = &_end_heap as *const usize as usize;
+    let heap_end = heap_end.min(heap_start + 4096);
     let heap_size = heap_end - heap_start;
 
-    print("> stack_end:   ");
+    print("> stack_end(sym): ");
     print_usize(stack_end);
-    print("\n> heap_start:  ");
+    print("\n> heap_start:     ");
     print_usize(heap_start);
-    print("\n> heap_end:    ");
+    print("\n> heap_end:       ");
     print_usize(heap_end);
-    print("\n> heap_size:   ");
+    print("\n> heap_size:      ");
     print_usize(heap_size);
     print("\n");
 

rust_raytrace/src/low_level/uart.rs

@@ -6,46 +6,3 @@ pub fn print_char(ch: u8) {
         thr.write_volatile(ch);
     }
 }
-
-pub fn println(s: &str) {
-    print(s);
-    print_char('\n' as u8);
-}
-
-pub fn print(s: &str) {
-    s.chars().for_each(|c| print_char(c as u8));
-}
-
-#[inline(always)]
-fn print_hex_part(u: u8) {
-    match u {
-        0 => print("0"),
-        1 => print("1"),
-        2 => print("2"),
-        3 => print("3"),
-        4 => print("4"),
-        5 => print("5"),
-        6 => print("6"),
-        7 => print("7"),
-        8 => print("8"),
-        9 => print("9"),
-        10 => print("a"),
-        11 => print("b"),
-        12 => print("c"),
-        13 => print("d"),
-        14 => print("e"),
-        15 => print("f"),
-        _ => unreachable!(),
-    }
-}
-
-pub fn print_usize(u: usize) {
-    print("0x");
-    for i in 0..=3 {
-        let part = ((u >> ((3 - i) * 8)) & 0xff) as u8;
-        let l = part & 0xF;
-        let h = (part >> 4) & 0xF;
-        print_hex_part(h);
-        print_hex_part(l);
-    }
-}

rust_raytrace/src/main.rs

@@ -10,30 +10,42 @@ extern crate alloc;
 mod low_level;
 use low_level::*;
 
+mod output;
+use output::*;
+
 mod raytrace;
 use raytrace::*;
 
 mod math;
 use math::*;
 
-const RAM_BASE: u32 = 0x80000000;
+mod fb;
-const FB_START: u32 = 0x80000;
+use fb::*;
-const FB_WIDTH: u32 = 2048;
-const FB_HEIGHT: u32 = 2048 - 16 /* progmem */ - 128 /* CPU state */;
-// const AA_BORDER: u32 = 10;
 
-static mut SUPERSCALE: u32 = 96; // start at 48
+mod text;
-pub fn superscale() -> u32 {
+use text::*;
-    unsafe { SUPERSCALE }
+
-}
+// const AA_BORDER: u32 = 10;
+const SUPERSCALE: u32 = 112;
 
 #[no_mangle]
 pub fn main() -> ! {
+    print("hartid (core) = ");
+    print_usize(hartid());
+    println("");
+
     println("Initializing heap...");
     unsafe {
         init_heap();
     }
 
+    if hartid() == 7 {
+        println("Starting text rendering loop...");
+        println("\nThis core is responsible for printing all the\ntext you see here, while the other 7 are\nrunning the raytracing algorithm.");
+        println("\nThe image will gradually gain more resolution,\nand if you let it run, it will eventually be\npixel perfect!");
+        render_text();
+    }
+
     println("Setting up scene...");
 
     let mut scene = Scene::new();
@@ -132,25 +144,30 @@ pub fn main() -> ! {
         intensity: 0.07,
     });
 
-    while superscale() > 1 {
+    let mut superscale = SUPERSCALE;
-        unsafe { SUPERSCALE /= 2 };
+    let starty = FB_HEIGHT_SLICE * hartid() as u32;
+
+    while superscale > 1 {
+        superscale /= 2;
         print("Tracing @");
-        print_usize(superscale() as usize);
+        print_usize(superscale as usize);
         print(" ");
 
-        for y in (0..(FB_HEIGHT / superscale())).rev() {
+        let sy = starty/superscale;
-            for x in 0..(FB_WIDTH / superscale()) {
+        for y in sy..(FB_HEIGHT_SLICE / superscale + sy) {
+            for x in 0..(FB_WIDTH / superscale) {
                 // Testpattern:
-                // let col = Vector3::new(
+                // let col = Color {
-                //     if (x % 2) == 0 { 255 } else { 0 },
+                //     r: if (x % 2) == 0 { 255 } else { 0 },
-                //     ((y * 255) / (FB_HEIGHT / superscale())) as i32,
+                //     g: (y * 255) / (FB_HEIGHT / superscale),
-                //     if (y % 2) == 0 { 255 } else { 0 },
+                //     b: if (y % 2) == 0 { 255 } else { 0 },
-                // );
+                // };
                 let col = scene.raytrace(
-                    x as i32 - (FB_WIDTH / superscale() / 2) as i32,
+                    x as i32 - (FB_WIDTH / superscale / 2) as i32,
-                    y as i32 - (FB_HEIGHT / superscale() / 2) as i32,
+                    y as i32 - ((FB_HEIGHT - FB_HEIGHT_SLICE) / superscale / 2) as i32,
+                    superscale,
                 );
-                write_px(x, y, col);
+                write_px(x, y, col, superscale);
             }
 
             print(".");
@@ -158,7 +175,7 @@ pub fn main() -> ! {
 
         // print(" Done!\nAnti-Aliasing");
 
-        // for y in 0..(FB_HEIGHT / superscale()) {
+        // for y in 0..(FB_HEIGHTxxx / superscale()) {
         //     for x in 0..(FB_WIDTH / superscale()) {
         //         // tap neighboring pixels and mix into borders
         //         let cur = read_px_raw(x * superscale() + superscale() / 2, y * superscale() + superscale() / 2);
@@ -205,26 +222,24 @@ pub fn main() -> ! {
     loop {}
 }
 
-fn write_px(x: u32, y: u32, col: Color) {
+fn write_px(x: u32, y: u32, col: Color, superscale: u32) {
-    let col = col.to_u128();
+    let x = x * superscale;
-    let x = x * superscale();
+    let y = y * superscale;
-    let y = y * superscale();
 
-    for ys in 0..superscale() {
+    if superscale > 7 {
-        for xs in 0..superscale() {
+        unsafe { write_px_memop(x, y+32, col, superscale); }
+        return;
+    }
+
+    let col = col.to_u128();
+
+    for ys in 0..superscale {
+        for xs in 0..superscale {
             write_px_raw(x + xs, y + ys, col);
         }
     }
 }
 
-fn write_px_raw(x: u32, y: u32, col: u128) {
-    unsafe {
-        let ptr = (FB_START | RAM_BASE) as *mut u128;
-        let ptr = ptr.add((x + y * FB_WIDTH) as usize);
-        ptr.write(col);
-    }
-}
-
 // fn read_px_raw(x: u32, y: u32) -> Color {
 //     let col: u128;
 //     unsafe {

rust_raytrace/src/output.rs

@@ -0,0 +1,44 @@
+use super::text::print_char;
+
+pub fn println(s: &str) {
+    print(s);
+    print_char('\n' as u8);
+}
+
+pub fn print(s: &str) {
+    s.chars().for_each(|c| print_char(c as u8));
+}
+
+#[inline(always)]
+fn print_hex_part(u: u8) {
+    match u {
+        0 => print("0"),
+        1 => print("1"),
+        2 => print("2"),
+        3 => print("3"),
+        4 => print("4"),
+        5 => print("5"),
+        6 => print("6"),
+        7 => print("7"),
+        8 => print("8"),
+        9 => print("9"),
+        10 => print("a"),
+        11 => print("b"),
+        12 => print("c"),
+        13 => print("d"),
+        14 => print("e"),
+        15 => print("f"),
+        _ => unreachable!(),
+    }
+}
+
+pub fn print_usize(u: usize) {
+    print("0x");
+    for i in 0..=3 {
+        let part = ((u >> ((3 - i) * 8)) & 0xff) as u8;
+        let l = part & 0xF;
+        let h = (part >> 4) & 0xF;
+        print_hex_part(h);
+        print_hex_part(l);
+    }
+}

rust_raytrace/src/raytrace.rs

@@ -172,17 +172,17 @@ impl Scene {
         self.lights.push(light);
     }
 
-    fn view_vector(x: i32, y: i32) -> Vector3 {
+    fn view_vector(x: i32, y: i32, superscale: u32) -> Vector3 {
         Vector3::new(
             x as f32,
             y as f32,
-            (crate::FB_WIDTH / crate::superscale() / 2) as f32,
+            (crate::FB_WIDTH / superscale / 2) as f32,
         )
         .normalized()
     }
 
-    pub fn raytrace(&self, x: i32, y: i32) -> Color {
+    pub fn raytrace(&self, x: i32, y: i32, superscale: u32) -> Color {
-        let view = Self::view_vector(x, y);
+        let view = Self::view_vector(x, y, superscale);
         self.do_raytrace(
             &Vector3::ZERO,
             &view,

rust_raytrace/src/text.rs

@@ -0,0 +1,238 @@
+use super::fb::*;
+use super::low_level::hartid;
+use super::math::Color;
+
+const BITMAP_FONT: [(u32, u32); 96] = [
+    (0, 0),                   // 0  32 ' '
+    (4472896, 4472896), // 1  33 '!' // 0100 0100 0100 0000 0100 0000      0100 0100 0100 0000 0100 0000
+    (11141120, 11141120), // 2  34 '"' // 1010 1010 0000 0000 0000 0000      1010 1010 0000 0000 0000 0000
+    (11447968, 11447968), // 3  35 '#' // 1010 1110 1010 1110 1010 0000      1010 1110 1010 1110 1010 0000
+    (5162720, 5162724), // 4  36 '$' // 0100 1110 1100 0110 1110 0000      0100 1110 1100 0110 1110 0100
+    (0, 0),             // 5  37 '%' // NOT WRITTEN
+    (4868704, 15395552), // 6  38 '&' // 0100 1010 0100 1010 0110 0000      1110 1010 1110 1010 1110 0000
+    (4456448, 4456448), // 7  39 ''' // 0100 0100 0000 0000 0000 0000      1110 1010 1110 1010 1110 0000
+    (2376736, 6571104), // 8  40 '(' // 0010 0100 0100 0100 0010 0000      0110 0100 0100 0100 0110 0000
+    (8668288, 12862656), // 9  41 ')' // 1000 0100 0100 0100 1000 0000      1100 0100 0100 0100 1100 0000
+    (674304, 978432), // 10 42 '*' // 0000 1010 0100 1010 0000 0000      0000 1110 1110 1110 0000 0000
+    (320512, 320512), // 11 43 '+' // 0000 0100 1110 0100 0000 0000      0000 0100 1110 0100 0000 0000
+    (1088, 1228), // 12 44 ',' // 0000 0000 0000 0100 0100 0000      0000 0000 0000 0100 1100 1100
+    (57344, 57344), // 13 45 '-' // 0000 0000 1110 0000 0000 0000      0000 0000 1110 0000 0000 0000
+    (64, 64),     // 14 46 '.' // 0000 0000 0000 0000 0100 0000      0000 0000 0000 0000 0100 0000
+    (2246784, 2287744), // 15 47 '/' // 0010 0010 0100 1000 1000 0000      0010 0010 1110 1000 1000 0000
+    (6990528, 15379168), // 16 48 '0' // 0110 1010 1010 1010 1100 0000      1110 1010 1010 1010 1110 0000
+    (4998368, 4998368), // 17 49 '1' // 0100 1100 0100 0100 1110 0000      0100 1100 0100 0100 1110 0000
+    (14870752, 14870752), // 18 50 '2' // 1110 0010 1110 1000 1110 0000      1110 0010 1110 1000 1110 0000
+    (14828256, 14836448), // 19 51 '3' // 1110 0010 0100 0010 1110 0000      1110 0010 0110 0010 1110 0000
+    (9101856, 9101856), // 20 52 '4' // 1000 1010 1110 0010 0010 0000      1000 1010 1110 0010 0010 0000
+    (15262432, 15262432), // 21 53 '5' // 1110 1000 1110 0010 1110 0000      1110 1000 1110 0010 1110 0000
+    (6875872, 15264480), // 22 54 '6' // 0110 1000 1110 1010 1110 0000      1110 1000 1110 1010 1110 0000
+    (14829120, 14836800), // 23 55 '7' // 1110 0010 0100 0110 0100 0000      1110 0010 0110 0100 0100 0000
+    (15395552, 15395552), // 24 56 '8' // 1110 1010 1110 1010 1110 0000      1110 1010 1110 1010 1110 0000
+    (15393472, 15393504), // 25 57 '9' // 1110 1010 1110 0010 1100 0000      1110 1010 1110 0010 1110 0000
+    (263168, 263168), // 26 58 ':' // 0000 0100 0000 0100 0000 0000      0000 0100 0000 0100 0000 0000
+    (263232, 263244), // 27 59 ';' // 0000 0100 0000 0100 0100 0000      0000 0100 0000 0100 0100 1100
+    (2393120, 7261792), // 28 60 '<' // 0010 0100 1000 0100 0010 0000      0110 1110 1100 1110 0110 0000
+    (921088, 921088), // 29 61 '=' // 0000 1110 0000 1110 0000 0000      0000 1110 0000 1110 0000 0000
+    (8660096, 13528768), // 30 62 '>' // 1000 0100 0010 0100 1000 0000      1100 1110 0110 1110 1100 0000
+    (12730432, 14836800), // 31 63 '?' // 1100 0010 0100 0000 0100 0000      1110 0010 0110 0100 0100 0000
+    (0, 0),               // 32 64 '@' // NOT WRITTEN
+    (15395488, 15395488), // 33 65 'A' // 1110 1010 1110 1010 1010 0000      1110 1010 1110 1010 1010 0000
+    (15387360, 15395552), // 34 66 'B' // 1110 1010 1100 1010 1110 0000      1110 1010 1110 1010 1110 0000
+    (15239392, 15239392), // 35 67 'C' // 1110 1000 1000 1000 1110 0000      1110 1000 1000 1000 1110 0000
+    (13281984, 15379168), // 36 68 'D' // 1100 1010 1010 1010 1100 0000      1110 1010 1010 1010 1110 0000
+    (15255776, 15255776), // 37 69 'E' // 1110 1000 1100 1000 1110 0000      1110 1000 1100 1000 1110 0000
+    (15255680, 15255680), // 38 70 'F' // 1110 1000 1100 1000 1000 0000      1110 1000 1100 1000 1000 0000
+    (15248096, 15248096), // 39 71 'G' // 1110 1000 1010 1010 1110 0000      1110 1000 1010 1010 1110 0000
+    (11201184, 11201184), // 40 72 'H' // 1010 1010 1110 1010 1010 0000      1010 1010 1110 1010 1010 0000
+    (14959840, 14959840), // 41 73 'I' // 1110 0100 0100 0100 1110 0000      1110 0100 0100 0100 1110 0000
+    (2239200, 2239200), // 42 74 'J' // 0010 0010 0010 1010 1110 0000      0010 0010 0010 1010 1110 0000
+    (11192992, 11201184), // 43 75 'K' // 1010 1010 1100 1010 1010 0000      1010 1010 1110 1010 1010 0000
+    (8947936, 8947936), // 44 76 'L' // 1000 1000 1000 1000 1110 0000      1000 1000 1000 1000 1110 0000
+    (11463328, 15657632), // 45 77 'M' // 1010 1110 1110 1010 1010 0000      1110 1110 1110 1010 1010 0000
+    (13281952, 15379104), // 46 78 'N' // 1100 1010 1010 1010 1010 0000      1110 1010 1010 1010 1010 0000
+    (15379168, 15379168), // 47 79 'O' // 1110 1010 1010 1010 1110 0000      1110 1010 1010 1010 1110 0000
+    (15394944, 15394944), // 48 80 'P' // 1110 1010 1110 1000 1000 0000      1110 1010 1110 1000 1000 0000
+    (15379040, 15379168), // 49 81 'Q' // 1110 1010 1010 1010 0110 0000      1110 1010 1010 1010 1110 0000
+    (15387296, 15395488), // 50 82 'R' // 1110 1010 1100 1010 1010 0000      1110 1010 1110 1010 1010 0000
+    (6873792, 15262432), // 51 83 'S' // 0110 1000 1110 0010 1100 0000      1110 1000 1110 0010 1110 0000
+    (14959680, 14959680), // 52 84 'T' // 1110 0100 0100 0100 0100 0000      1110 0100 0100 0100 0100 0000
+    (11184736, 11184864), // 53 85 'U' // 1010 1010 1010 1010 0110 0000      1010 1010 1010 1010 1110 0000
+    (11445472, 11202112), // 54 86 'V' // 1010 1110 1010 0100 1110 0000      1010 1010 1110 1110 0100 0000
+    (11202208, 11202272), // 55 87 'W' // 1010 1010 1110 1110 1010 0000      1010 1010 1110 1110 1110 0000
+    (11160224, 11201184), // 56 88 'X' // 1010 1010 0100 1010 1010 0000      1010 1010 1110 1010 1010 0000
+    (15352896, 11420736), // 57 89 'Y' // 1110 1010 0100 0100 0100 0000      1010 1110 0100 0100 0100 0000
+    (14829792, 14870752), // 58 90 'Z' // 1110 0010 0100 1000 1110 0000      1110 0010 1110 1000 1110 0000
+    (0, 0),               // 59 91 '[' // NOT WRITTEN
+    (0, 0),               // 60 92 '\' // NOT WRITTEN
+    (0, 0),               // 61 93 ']' // NOT WRITTEN
+    (4849664, 15597568), // 62 94 '^' // 0100 1010 0000 0000 0000 0000      1110 1110 0000 0000 0000 0000
+    (224, 224), // 63 95 '_' // 0000 0000 0000 0000 1110 0000      0000 0000 0000 0000 1110 0000
+    (0, 0),     // 64 96 '`' // NOT WRITTEN
+    (436832, 961248), // 65 97 'a' // 0000 0110 1010 1010 0110 0000      0000 1110 1010 1010 1110 0000
+    (9349856, 9349856), // 66 98 'b' // 1000 1110 1010 1010 1110 0000      1000 1110 1010 1010 1110 0000
+    (952544, 952544), // 67 99 'c' // 0000 1110 1000 1000 1110 0000      0000 1110 1000 1000 1110 0000
+    (3058400, 3058400), // 68 100 'd' // 0010 1110 1010 1010 1110 0000      0010 1110 1010 1010 1110 0000
+    (961760, 962272), // 69 101 'e' // 0000 1110 1010 1100 1110 0000      0000 1110 1010 1110 1110 0000
+    (6612032, 6612032), // 70 102 'f' // 0110 0100 1110 0100 0100 0000      0110 0100 1110 0100 0100 0000
+    (976608, 962272), // 71 103 'g' // 0000 1110 1110 0110 1110 0000      0000 1110 1010 1110 1110 0000
+    (9349792, 9349792), // 72 104 'h' // 1000 1110 1010 1010 1010 0000      1000 1110 1010 1010 1010 0000
+    (4474080, 4867296), // 73 105 'i' // 0100 0100 0100 0100 1110 0000      0100 1010 0100 0100 1110 0000
+    (2239200, 2435808), // 74 106 'j' // 0010 0010 0010 1010 1110 0000      0010 0101 0010 1010 1110 0000
+    (9096352, 9105056), // 75 107 'k' // 1000 1010 1100 1100 1010 0000      1000 1010 1110 1110 1010 0000
+    (4474080, 12862688), // 76 108 'l' // 0100 0100 0100 0100 1110 0000      1100 0100 0100 0100 1110 0000
+    (715424, 977568), // 77 109 'm' // 0000 1010 1110 1010 1010 0000      0000 1110 1110 1010 1010 0000
+    (830112, 961184), // 78 110 'n' // 0000 1100 1010 1010 1010 0000      0000 1110 1010 1010 1010 0000
+    (961248, 961248), // 79 111 'o' // 0000 1110 1010 1010 1110 0000      0000 1110 1010 1010 1110 0000
+    (962176, 962176), // 80 112 'p' // 0000 1110 1010 1110 1000 0000      0000 1110 1010 1110 1000 0000
+    (962080, 962080), // 81 113 'q' // 0000 1110 1010 1110 0010 0000      0000 1110 1010 1110 0010 0000
+    (714880, 968832), // 82 114 'r' // 0000 1010 1110 1000 1000 0000      0000 1110 1100 1000 1000 0000
+    (968416, 968416), // 83 115 's' // 0000 1110 1100 0110 1110 0000      0000 1110 1100 0110 1110 0000
+    (5129280, 5129280), // 84 116 't' // 0100 1110 0100 0100 0100 0000      0100 1110 0100 0100 0100 0000
+    (699104, 699104), // 85 117 'u' // 0000 1010 1010 1010 1110 0000      0000 1010 1010 1010 1110 0000
+    (715328, 700128), // 86 118 'v' // 0000 1010 1110 1010 0100 0000      0000 1010 1010 1110 1110 0000
+    (700064, 700128), // 87 119 'w' // 0000 1010 1010 1110 1010 0000      0000 1010 1010 1110 1110 0000
+    (672928, 716448), // 88 120 'x' // 0000 1010 0100 0100 1010 0000      0000 1010 1110 1110 1010 0000
+    (713312, 713440), // 89 121 'y' // 0000 1010 1110 0010 0110 0000      0000 1010 1110 0010 1110 0000
+    (945376, 945376), // 90 122 'z' // 0000 1110 0110 1100 1110 0000      0000 1110 0110 1100 1110 0000
+    (0, 0),           // 91 123 '(' // NOT WRITTEN
+    (0, 0),           // 92 124 '|' // NOT WRITTEN
+    (0, 0),           // 93 125 ')' // NOT WRITTEN
+    (0, 0),           // 94 126 '~' // NOT WRITTEN
+    (0xffffffff, 0xffffffff), // 95 127 ERROR SQUARE
+];
+
+fn draw_char(ch: u8, px: u32, py: u32, scale: u32, col: &Color) {
+    let ch = if ch == 0 { 127 } else { ch };
+    if ch < 32 || ch > 127 {
+        return;
+    }
+    let bitmap_a: u32 = BITMAP_FONT[(ch - 32) as usize].0;
+    let bitmap_b: u32 = BITMAP_FONT[(ch - 32) as usize].1;
+    if scale <= 2 {
+        for x in 0..(4 * scale) {
+            for y in 0..(6 * scale) {
+                if ((bitmap_a >> (5 - (y / scale)) * 4) >> (4 - (x / scale))) & 1 == 1 {
+                    if ((bitmap_b >> (5 - (y / scale)) * 4) >> (4 - (x / scale))) & 1 == 1 {
+                        write_px_raw(px + x, py + y, col.to_u128());
+                    }
+                }
+            }
+        }
+    } else {
+        for x in 0..4 {
+            for y in 0..6 {
+                if ((bitmap_a >> (5 - y) * 4) >> (4 - x)) & 1 == 1 {
+                    if ((bitmap_b >> (5 - y) * 4) >> (4 - x)) & 1 == 1 {
+                        unsafe {
+                            write_px_memop(
+                                px + x * scale,
+                                py + y * scale,
+                                col.clone(),
+                                scale,
+                            );
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn draw_line<S: AsRef<str>>(s: S, px: u32, py: u32, scale: u32, col: &Color) {
+    let s = s.as_ref();
+    let mut i = 0;
+    for c in s.bytes() {
+        draw_char(c, px + i * 5 * scale, py, scale, &col);
+        i += 1;
+    }
+}
+
+// defined by linker script
+extern "C" {
+    static _end_textbuf: usize;
+}
+
+/// put a character into the buffer for the output hart to read and print
+unsafe fn print_char_unsafe(ch: u8) {
+    // calculate text buffer base
+    let end_textbuf = &_end_textbuf as *const usize as usize;
+    let tbase = (end_textbuf - hartid() * 4096) as *mut usize;
+    let cur_ptr = tbase.read_volatile();
+    if cur_ptr == 4096 {
+        // TODO: make work lol
+        return;
+    }
+    // this works because while write visibility is not synchronized, the order
+    // in which writes appear is always upheld
+    ((cur_ptr + tbase as usize + 4) as *mut u8).write_unaligned(ch);
+    tbase.write_volatile(cur_ptr + 1);
+}
+
+pub fn print_char(ch: u8) {
+    unsafe {
+        print_char_unsafe(ch);
+    }
+}
+
+const STARTY: u32 = 1622;
+const HEADER: &str = "rvc (RISC-V CPU emulator) by _pi_";
+const HEADER_REPO: &str = "github.com/pimaker/rvc";
+const HEADER_STATE: &str = "above: main memory (which doubles as framebuffer)";
+const HEADER_TEXT: &str = "below: hart nr. 8 collects text output from others and draws it";
+const WHITE: Color = Color { r: 255, g: 255, b: 255 };
+const GRAY: Color = Color { r: 120, g: 120, b: 120 };
+const PURPLE: Color = Color { r: 255, g: 40, b: 255 };
+pub fn render_text() -> ! {
+    draw_line(HEADER, 1024, STARTY, 6, &PURPLE);
+    draw_line(HEADER_REPO, 1024, STARTY + 36, 3, &GRAY);
+    draw_line(HEADER_STATE, 16, STARTY, 3, &WHITE);
+    draw_line(HEADER_TEXT, 16, STARTY + 26, 3, &WHITE);
+    draw_line("(hart = core in risc-v)", 138, STARTY + 32, 1, &GRAY);
+
+    let mut ptrs = [0usize; 8];
+
+    // if I make this an array of (0, 0) tuples it doesn't work - bug somewhere?
+    let mut pos_x = [0; 8];
+    let mut pos_y = [0; 8];
+
+    loop {
+        for hart in (0..8).rev() {
+            unsafe {
+                let end_textbuf = &_end_textbuf as *const usize as usize;
+                let tbase = (end_textbuf - hart * 4096) as *const usize;
+                let cur_ptr = tbase.read();
+                while ptrs[hart] < cur_ptr {
+                    let ch = ((ptrs[hart] + tbase as usize + 4) as *const u8).read_unaligned();
+                    // if ch != 0 {
+                    //     super::low_level::uart::print_char(ch);
+                    // } else {
+                    //     super::low_level::uart::print_char('0' as u8);
+                    // }
+                    ptrs[hart] += 1;
+                    if ch == ('\n' as u8) {
+                        pos_x[hart] = 0;
+                        pos_y[hart] += 1;
+                    } else {
+                        draw_char(
+                            ch,
+                            pos_x[hart] * 5 + hart as u32 * 48 * 5 + 16,
+                            pos_y[hart] * 7 + 64 + STARTY,
+                            1,
+                            if hart == 7 { &WHITE } else { &GRAY },
+                        );
+                        pos_x[hart] += 1;
+                        if pos_x[hart] >= 48 {
+                            pos_x[hart] = 0;
+                            pos_y[hart] += 1;
+                        }
+                    }
+                }
+            }
+        }
+
+        // stall, we know that without a new commit cycle no new data will come
+        unsafe {
+            asm! { "fence.i" }
+        }
+    }
+}

src/cpu.h

@@ -4,6 +4,7 @@
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
+#include <sys/time.h>
 #include "types.h"
 #include "mem.h"
 #include "emu.h"
@@ -26,6 +27,9 @@ cpu_t cpu_init(uint8_t *mem, uint8_t *dtb, uint8_t *mtd, uint mtd_size) {
     ret.mtd = mtd;
     ret.mtd_size = mtd_size;
 
+    ret.net.netrx = malloc(4096);
+    ret.net.nettx = malloc(4096);
+
     ret.clint.msip = false;
     ret.clint.mtimecmp_lo = 0;
     ret.clint.mtimecmp_hi = 0;
@@ -40,6 +44,8 @@ cpu_t cpu_init(uint8_t *mem, uint8_t *dtb, uint8_t *mtd, uint mtd_size) {
     ret.mmu.mode = 0;
     ret.mmu.ppn = 0;
 
+    ret.start_time_ref = _Time;
+
     return ret;
 }
 

src/csr.h

@@ -3,9 +3,11 @@
 
 #include <stdbool.h>
 #include <stdio.h>
+#include <time.h>
 #include "types.h"
 #include "trap.h"
 #include "mmu.h"
+#include "net.h"
 
 const uint CSR_USTATUS = 0x000;
 const uint CSR_UIE = 0x004;
@@ -50,11 +52,33 @@ const uint CSR_MEMOP_SRC = 0x0b1;
 const uint CSR_MEMOP_DST = 0x0b2;
 const uint CSR_MEMOP_N = 0x0b3;
 
+const uint CSR_PLAYER_ID = 0xbe;
+const uint CSR_RNG = 0x0bf;
+
+const uint CSR_NET_TX_BUF_ADDR = 0x0c0;
+const uint CSR_NET_TX_BUF_SIZE_AND_SEND = 0x0c1;
+const uint CSR_NET_RX_BUF_ADDR = 0x0c2;
+const uint CSR_NET_RX_BUF_READY = 0x0c3;
+
 #define MMU_ACCESS_FETCH 0
 #define MMU_ACCESS_READ 1
 #define MMU_ACCESS_WRITE 2
 extern uint mmu_translate(ins_ret *ins, uint addr, uint mode);
 
+uint xorshift(uint seed) {
+    seed ^= seed << 13;
+    seed ^= seed >> 17;
+    seed ^= seed << 5;
+    return seed;
+}
+
+uint rng() {
+    // assume this always works I'm too lazy to error check
+    struct timespec ts;
+    clock_gettime(CLOCK_REALTIME, &ts);
+    return xorshift(ts.tv_nsec);
+}
+
 bool has_csr_access_privilege(cpu_t *cpu, uint addr) {
     uint privilege = (addr >> 8) & 0x3;
     return privilege <= cpu->csr.privilege;
@@ -71,11 +95,16 @@ uint read_csr_raw(cpu_t *cpu, uint address) {
         case CSR_CYCLE: return cpu->clock;
         case CSR_MHARTID: return 0;
         case CSR_SATP: return (cpu->mmu.mode << 31) | cpu->mmu.ppn;
+        case CSR_RNG: return rng();
+        case CSR_PLAYER_ID: return is_server() ? 2 : 1;
+        case CSR_NET_TX_BUF_ADDR: return 0x11000000;
+        case CSR_NET_RX_BUF_ADDR: return 0x11001000;
         default: return cpu->csr.data[address & 0xffff];
     }
 }
 
 void write_csr_raw(cpu_t *cpu, uint address, uint value) {
+
     switch (address) {
         case CSR_SSTATUS:
             cpu->csr.data[CSR_MSTATUS] &= ~0x000de162;
@@ -102,9 +131,34 @@ void write_csr_raw(cpu_t *cpu, uint address, uint value) {
                 uint src = mmu_translate(&ins, cpu->csr.data[CSR_MEMOP_SRC], MMU_ACCESS_READ);
                 uint dst = mmu_translate(&ins, cpu->csr.data[CSR_MEMOP_DST], MMU_ACCESS_WRITE);
                 uint n = cpu->csr.data[CSR_MEMOP_N];
-                memcpy(&cpu->mem[dst & (~0x80000000)], &cpu->mem[src & (~0x80000000)], n);
+                uint8_t *srcb, *dstb;
+                // FIXME: can still crash with non-ram and non-mtd addresses
+                if (src & 0x80000000) {
+                    srcb = cpu->mem;
+                    src &= ~0x80000000;
+                } else {
+                    srcb = cpu->mtd;
+                    src &= ~0x40000000;
+                    src %= cpu->mtd_size;
+                }
+                if (dst & 0x80000000) {
+                    dstb = cpu->mem;
+                    dst &= ~0x80000000;
+                } else {
+                    dstb = cpu->mtd;
+                    dst &= ~0x40000000;
+                    dst %= cpu->mtd_size - n; // FIXME: incorrect for boundary
+                }
+                memcpy(dstb + dst, srcb + src, n);
             }
             break;
+        case CSR_NET_TX_BUF_SIZE_AND_SEND:
+            /* cpu->csr.data[address] = value; */
+            net_send(cpu->net.nettx, value);
+            break;
+        case CSR_NET_RX_BUF_READY:
+            cpu->net.rx_ready = value;
+            break;
         default: cpu->csr.data[address] = value; break;
     };
 }

src/emu.h

@@ -3,12 +3,15 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/time.h>
+#include <math.h>
 #include "types.h"
 #include "ins.h"
 #include "mem.h"
 #include "mmu.h"
 #include "trap.h"
 #include "csr.h"
+#include "net.h"
 
 #include "pngout.h"
 static int ebreak_png = 0;
@@ -202,10 +205,12 @@ DEF(divu, FormatR, { // rv32m
     }
     WR_RD(result)
 })
+extern void cpu_dump(cpu_t *cpu);
 DEF(ebreak, FormatEmpty, { // system
     printf("EBREAK!\n");
-    VERBOSE=4;
+    cpu_dump(cpu);
-    SINGLE_STEP=1;
+    /* VERBOSE=4; */
+    /* SINGLE_STEP=1; */
     /* char buf[12]; */
     /* sprintf(buf, "ram_%d.png", ebreak_png++); */
     /* int ret = write_ram_as_png(buf); */
@@ -597,6 +602,10 @@ ins_ret ins_select(cpu_t *cpu, uint ins_word) {
 
 
 void emulate(cpu_t *cpu) {
+    bool net_has_data;
+    uint8_t *net_data;
+    uint32_t net_data_len;
+
     uint ins_word = 0;
     ins_ret ret = ins_ret_noop(cpu);
     if ((cpu->pc & 0x3) == 0) {
@@ -624,19 +633,38 @@ void emulate(cpu_t *cpu) {
         cpu->csr.data[CSR_MIP] |= MIP_MSIP;
     }
 
-    cpu->clint.mtime_lo++;
+    double mtime = _Time * 1000000.0 / 20.0 * 0.1;
-    cpu->clint.mtime_hi += cpu->clint.mtime_lo == 0 ? 1 : 0;
+    cpu->clint.mtime_lo = (uint)(fmod(mtime, 4294967296.0)); // & 0xffffffff
+    cpu->clint.mtime_hi = (uint)(mtime / 4294967296.0); // >> 32
 
     if ((cpu->clint.mtimecmp_lo != 0 || cpu->clint.mtimecmp_hi != 0) && (cpu->clint.mtime_hi > cpu->clint.mtimecmp_hi || (cpu->clint.mtime_hi == cpu->clint.mtimecmp_hi && cpu->clint.mtime_lo >= cpu->clint.mtimecmp_lo))) {
         cpu->csr.data[CSR_MIP] |= MIP_MTIP;
-        if (VERBOSE >= 1)
+        if (VERBOSE >= 4)
             printf("timer irq: %d >= %d\n", cpu->clint.mtime_lo, cpu->clint.mtimecmp_lo);
     }
 
     uart_tick(cpu);
-    if (cpu->uart.interrupting) {
+    uint cur_mip = read_csr_raw(cpu, CSR_MIP);
-        uint cur_mip = read_csr_raw(cpu, CSR_MIP);
+    if (!(cur_mip & MIP_SEIP)) {
-        write_csr_raw(cpu, CSR_MIP, cur_mip | MIP_SEIP);
+        if (cpu->uart.interrupting) {
+            // uart interrupt
+            write_csr_raw(cpu, CSR_MIP, cur_mip | MIP_SEIP);
+        } else if (cpu->net.rx_ready) {
+            net_has_data = net_recv(&net_data, &net_data_len);
+            if (net_has_data) {
+                // network interrupt
+                write_csr_raw(cpu, CSR_MIP, cur_mip | MIP_SEIP);
+                uint8_t *dmabuf = cpu->net.netrx;
+                if (net_data_len > 4096 - sizeof(uint32_t)) {
+                    // maximum of one page size
+                    net_data_len = 4096 - sizeof(uint32_t);
+                }
+                *((uint32_t*)dmabuf) = net_data_len;
+                memcpy(dmabuf + sizeof(uint32_t), net_data, net_data_len);
+                cpu->net.rx_ready = false;
+                free(net_data);
+            }
+        }
     }
 
     handle_irq_and_trap(cpu, &ret);

src/main.c

@@ -8,9 +8,11 @@
 #include <unistd.h>
 #include <signal.h>
 #include <time.h>
+#include <sys/time.h>
 #include "types.h"
 #include "cpu.h"
 #include "uart.h"
+#include "net.h"
 #include <termios.h>
 
 #include "../elfy/elfy.h"
@@ -59,30 +61,47 @@ uint8_t* get_mmap_ptr(const char* filename) {
 }
 
 void usage() {
-    printf("Usage: rvc (-e <ELF binary>|-b <raw binary>) [-d <device tree binary>] [-i <initramfs>] [-v (0|1|2|3|4)] [-s] [-t] [-x]\n");
+    printf("Usage: rvc (-e <ELF binary>|-b <raw binary>) [-d <device tree binary>] [-i <initramfs>] [-v (0|1|2|3|4)] [-s (single step)] [-t (trace)] [-x (allow exit ecall)] [-f (signal forward)] [-n <server socket path> / -N <client socket path>]\n");
     exit(EXIT_FAILURE);
 }
 
+static bool signal_forward = false;
+#define MAX_INPUT_STACK 128
+static char input_stack[MAX_INPUT_STACK];
+static uint input_stack_idx = 0;
+static time_t last_signal_time = 0;
+
 void term(int signum)
 {
-   printf("\n\nCaught signal!\n");
+    if (signal_forward) {
-   buf_on();
+        time_t cur_time = time(NULL);
-   cpu_dump(&cpu);
+        if (cur_time - last_signal_time >= 1) {
-   printf("\n");
+            last_signal_time = cur_time;
+            if (input_stack_idx > (MAX_INPUT_STACK - 2)) return;
+            /* input_stack[input_stack_idx++] = 0x1b; */
+            input_stack[input_stack_idx++] = 0x03; /* ETX / Ctrl-C */
+            return;
+        }
+    }
 
-   /* ins_ret ret; */
+    printf("\n\nCaught signal!\n");
-   /* for (uint i = 0x10000; i < 0x11000; i += 4) { */
+    buf_on();
-   /*     uint pa = mmu_translate(&ret, i, MMU_ACCESS_READ); */
+    cpu_dump(&cpu);
-   /*     uint val = mem_get_word(&cpu, pa); */
+    printf("\n");
-   /*     printf("%05x: %08x\n", i, val); */
-   /* } */
 
-   /* print_tracebuf(); */
+    /* ins_ret ret; */
+    /* for (uint i = 0x10000; i < 0x11000; i += 4) { */
+    /*     uint pa = mmu_translate(&ret, i, MMU_ACCESS_READ); */
+    /*     uint val = mem_get_word(&cpu, pa); */
+    /*     printf("%05x: %08x\n", i, val); */
+    /* } */
 
-   write_ram_as_png("ram.png");
+    /* print_tracebuf(); */
 
-   /* printf("\n"); */
+    /* write_ram_as_png("ram.png"); */
-   exit(EXIT_FAILURE);
+
+    /* printf("\n"); */
+    exit(EXIT_FAILURE);
 }
 
 int main(int argc, char *argv[]) {
@@ -92,12 +111,18 @@ int main(int argc, char *argv[]) {
     char *initrd = NULL;
     uint mtd_size = 0;
 
+    char *socket = NULL;
+    bool server = false;
+
     int c;
     bool trace = false;
 
-    while ((c = getopt (argc, argv, "e:b:d:v:i:stx")) != -1) {
+    while ((c = getopt (argc, argv, "e:b:d:v:i:n:N:stxf")) != -1) {
         switch (c)
         {
+            case 'f':
+                signal_forward = true;
+                break;
             case 'x':
                 allow_ecall_exit = true;
                 break;
@@ -122,6 +147,14 @@ int main(int argc, char *argv[]) {
             case 'i':
                 initrd = optarg;
                 break;
+            case 'n':
+                socket = optarg;
+                server = true;
+                break;
+            case 'N':
+                socket = optarg;
+                server = false;
+                break;
             case '?':
             default:
                 usage();
@@ -133,6 +166,7 @@ int main(int argc, char *argv[]) {
     }
 
     uint8_t *mem = malloc(MEM_SIZE);
+    memset(mem, 0, MEM_SIZE);
     if (elf) {
         if (load_elf(elf, strlen(elf) + 1, mem, MEM_SIZE, VERBOSE >= 1)) {
             exit(EXIT_FAILURE+1);
@@ -150,6 +184,10 @@ int main(int argc, char *argv[]) {
         memcpy(mtd, mtd_ptr, mtd_size);
     }
 
+    if (socket) {
+        net_init(socket, server);
+    }
+
     struct sigaction action;
     memset(&action, 0, sizeof(action));
     action.sa_handler = term;
@@ -170,12 +208,16 @@ int main(int argc, char *argv[]) {
     buf_off();
 
     // LIMITER (set to high number to ignore)
-    const unsigned long restr = 200000*1000;
+    const unsigned long restr = 200000*10000;
     unsigned long cur = 0;
     unsigned long t = time(NULL);
 
     uint init_verbose = VERBOSE;
 
+    struct timeval now;
+    gettimeofday(&now, NULL);
+    uint64_t base_clock = now.tv_sec;
+
     while (1) {
         cur++;
         unsigned long t2 = time(NULL);
@@ -187,6 +229,10 @@ int main(int argc, char *argv[]) {
             continue;
         }
 
+        gettimeofday(&now, NULL);
+        _Time = (float)((now.tv_sec - base_clock) * 1000000 + now.tv_usec) / 1000000.0f;
+        /* printf("Time: %lu %lu %.2f\n", now.tv_sec, now.tv_usec, _Time); */
+
         cpu_tick(&cpu);
 
         if (trace)
@@ -226,8 +272,24 @@ int main(int argc, char *argv[]) {
             cpu_dump(&cpu);
 
         char input = 0;
-        if (!SINGLE_STEP && !uart_input_value && read(0, &input, 1)) {
+        if (!SINGLE_STEP && input_stack_idx < MAX_INPUT_STACK && read(0, &input, 1)) {
-            uart_input_value = input;
+            /* if (input == '+') { */
+            /*     VERBOSE = (VERBOSE + 1) % 5; */
+            /*     printf("\nVERBOSE = %d\n", VERBOSE); */
+            /* } else { */
+            /*     uart_input_value = input; */
+            /* } */
+            if (input)
+                input_stack[input_stack_idx++] = input;
+        }
+
+        if (!uart_input_value && input_stack_idx > 0) {
+            uart_input_value = input_stack[0];
+            input_stack_idx--;
+            // shift stack forward
+            for (int i = 0; i < input_stack_idx; i++) {
+                input_stack[i] = input_stack[i+1];
+            }
         }
 
         if (SINGLE_STEP) {

src/mem.h

@@ -5,96 +5,113 @@
 #include <assert.h>
 #include "types.h"
 #include "uart.h"
+#include "rtc.h"
 
-const int MEM_SIZE = 1024 * 1024 * 64 - 2048 * 128;
+const int MEM_SIZE = 1024 * 1024 * 256 - 2048 * 128;
 
 // little endian, zero extended
 uint do_mem_get_byte(cpu_t *cpu, uint addr) {
 
-    if (cpu->dtb != NULL && addr >= 0x1020 && addr <= 0x1fff) {
-        if (VERBOSE >= 2)
-            printf("DTB read @%04x/%04x\n", addr, addr - 0x1020);
-        return cpu->dtb[addr - 0x1020];
-    }
-
-    /* if (cpu->mtd != NULL && addr >= 0x40000000 && addr < (0x40000000 + MEM_SIZE)) { */
-    /*     return cpu->mtd[addr - 0x40000000]; */
-    /* } */
-
-    switch (addr) {
-        // CLINT
-        case 0x02000000: return cpu->clint.msip ? 1 : 0;
-        case 0x02000001: return 0;
-        case 0x02000002: return 0;
-        case 0x02000003: return 0;
-
-        case 0x02004000: return (cpu->clint.mtimecmp_lo >> 0) & 0xFF;
-        case 0x02004001: return (cpu->clint.mtimecmp_lo >> 8) & 0xFF;
-        case 0x02004002: return (cpu->clint.mtimecmp_lo >> 16) & 0xFF;
-        case 0x02004003: return (cpu->clint.mtimecmp_lo >> 24) & 0xFF;
-        case 0x02004004: return (cpu->clint.mtimecmp_hi >> 0) & 0xFF;
-        case 0x02004005: return (cpu->clint.mtimecmp_hi >> 8) & 0xFF;
-        case 0x02004006: return (cpu->clint.mtimecmp_hi >> 16) & 0xFF;
-        case 0x02004007: return (cpu->clint.mtimecmp_hi >> 24) & 0xFF;
-
-        case 0x0200bff8: return (cpu->clint.mtime_lo >> 0) & 0xFF;
-        case 0x0200bff9: return (cpu->clint.mtime_lo >> 8) & 0xFF;
-        case 0x0200bffa: return (cpu->clint.mtime_lo >> 16) & 0xFF;
-        case 0x0200bffb: return (cpu->clint.mtime_lo >> 24) & 0xFF;
-        case 0x0200bffc: return (cpu->clint.mtime_hi >> 0) & 0xFF;
-        case 0x0200bffd: return (cpu->clint.mtime_hi >> 8) & 0xFF;
-        case 0x0200bffe: return (cpu->clint.mtime_hi >> 16) & 0xFF;
-        case 0x0200bfff: return (cpu->clint.mtime_hi >> 24) & 0xFF;
-
-        // UART (first has rbr_thr_ier_iir, second has lcr_mcr_lsr_scr)
-        case 0x10000000:
-            if ((UART_GET2(LCR) >> 7) == 0) {
-                uint rbr = UART_GET1(RBR);
-                UART_SET1(RBR, 0);
-                UART_SET2(LSR, (UART_GET2(LSR) & ~LSR_DATA_AVAILABLE));
-                uart_update_iir(cpu);
-                return rbr;
-            } else {
-                return 0;
-            }
-        case 0x10000001: return UART_GET2(LCR) >> 7 == 0 ? UART_GET1(IER) : 0;
-        case 0x10000002: return UART_GET1(IIR);
-        case 0x10000003: return UART_GET2(LCR);
-        case 0x10000004: return UART_GET2(MCR);
-        case 0x10000005: return UART_GET2(LSR);
-        case 0x10000007: return UART_GET2(SCR);
-
-        /* case 0x80001000: return 0; */
-        /* case 0x80001001: return 0; */
-        /* case 0x80001002: return 0; */
-        /* case 0x80001003: return 0; */
-        /* case 0x80001004: return 0; */
-        /* case 0x80001005: return 0; */
-        /* case 0x80001006: return 0; */
-        /* case 0x80001007: return 0; */
-        /* case 0x80001040: return 0; */
-        /* case 0x80001041: return 0; */
-        /* case 0x80001042: return 0; */
-        /* case 0x80001043: return 0; */
-        /* case 0x80001044: return 0; */
-        /* case 0x80001045: return 0; */
-        /* case 0x80001046: return 0; */
-        /* case 0x80001047: return 0; */
-    }
-
     if ((addr & 0x80000000) == 0) {
-        return 0;
+        if (cpu->dtb != NULL && addr >= 0x1020 && addr <= 0x1fff) {
-    }
+            if (VERBOSE >= 2)
+                printf("DTB read @%04x/%04x\n", addr, addr - 0x1020);
+            return cpu->dtb[addr - 0x1020];
+        }
+
+        if (cpu->mtd != NULL && addr >= 0x40000000 && addr < (0x40000000 + MEM_SIZE)) {
+            if (VERBOSE >= 3)
+                printf("MTD read @%08x/%04x\n", addr, addr - 0x40000000);
+            return cpu->mtd[addr - 0x40000000];
+        }
+
+        if (addr >= 0x11001000 && addr < (0x11001000 + 4096)) {
+            if (VERBOSE >= 3)
+                printf("NETRX read @%08x/%04x\n", addr, addr - 0x11001000);
+            return cpu->net.netrx[addr - 0x11001000];
+        }
+
+        // RTC, see device tree
+        if (addr >= 0x03000000 && addr < (0x03000000 + 0x800)) {
+            return rtc_read(cpu, addr - 0x03000000);
+        }
+
+        switch (addr) {
+            // CLINT
+            case 0x02000000: return cpu->clint.msip ? 1 : 0;
+            case 0x02000001: return 0;
+            case 0x02000002: return 0;
+            case 0x02000003: return 0;
+
+            case 0x02004000: return (cpu->clint.mtimecmp_lo >> 0) & 0xFF;
+            case 0x02004001: return (cpu->clint.mtimecmp_lo >> 8) & 0xFF;
+            case 0x02004002: return (cpu->clint.mtimecmp_lo >> 16) & 0xFF;
+            case 0x02004003: return (cpu->clint.mtimecmp_lo >> 24) & 0xFF;
+            case 0x02004004: return (cpu->clint.mtimecmp_hi >> 0) & 0xFF;
+            case 0x02004005: return (cpu->clint.mtimecmp_hi >> 8) & 0xFF;
+            case 0x02004006: return (cpu->clint.mtimecmp_hi >> 16) & 0xFF;
+            case 0x02004007: return (cpu->clint.mtimecmp_hi >> 24) & 0xFF;
+
+            case 0x0200bff8: return (cpu->clint.mtime_lo >> 0) & 0xFF;
+            case 0x0200bff9: return (cpu->clint.mtime_lo >> 8) & 0xFF;
+            case 0x0200bffa: return (cpu->clint.mtime_lo >> 16) & 0xFF;
+            case 0x0200bffb: return (cpu->clint.mtime_lo >> 24) & 0xFF;
+            case 0x0200bffc: return (cpu->clint.mtime_hi >> 0) & 0xFF;
+            case 0x0200bffd: return (cpu->clint.mtime_hi >> 8) & 0xFF;
+            case 0x0200bffe: return (cpu->clint.mtime_hi >> 16) & 0xFF;
+            case 0x0200bfff: return (cpu->clint.mtime_hi >> 24) & 0xFF;
+
+            // UART (first has rbr_thr_ier_iir, second has lcr_mcr_lsr_scr)
+            case 0x10000000:
+                if ((UART_GET2(LCR) >> 7) == 0) {
+                    uint rbr = UART_GET1(RBR);
+                    UART_SET1(RBR, 0);
+                    UART_SET2(LSR, (UART_GET2(LSR) & ~LSR_DATA_AVAILABLE));
+                    uart_update_iir(cpu);
+                    return rbr;
+                } else {
+                    return 0;
+                }
+            case 0x10000001: return UART_GET2(LCR) >> 7 == 0 ? UART_GET1(IER) : 0;
+            case 0x10000002: return UART_GET1(IIR);
+            case 0x10000003: return UART_GET2(LCR);
+            case 0x10000004: return UART_GET2(MCR);
+            case 0x10000005: return UART_GET2(LSR);
+            case 0x10000007: return UART_GET2(SCR);
+
+            /* case 0x80001000: return 0; */
+            /* case 0x80001001: return 0; */
+            /* case 0x80001002: return 0; */
+            /* case 0x80001003: return 0; */
+            /* case 0x80001004: return 0; */
+            /* case 0x80001005: return 0; */
+            /* case 0x80001006: return 0; */
+            /* case 0x80001007: return 0; */
+            /* case 0x80001040: return 0; */
+            /* case 0x80001041: return 0; */
+            /* case 0x80001042: return 0; */
+            /* case 0x80001043: return 0; */
+            /* case 0x80001044: return 0; */
+            /* case 0x80001045: return 0; */
+            /* case 0x80001046: return 0; */
+            /* case 0x80001047: return 0; */
+        }
 
-    addr = addr & 0x7FFFFFFF;
-    if (addr >= MEM_SIZE) {
         if (VERBOSE >= 1) {
-            printf("WARN: out-of-bounds memory read @0x%08x\n", addr | 0x80000000);
+            printf("WARN: out-of-bounds mmio read @0x%08x\n", addr);
         }
         return 0;
-    }
+    } else {
+        addr = addr & 0x7FFFFFFF;
+        if (addr >= MEM_SIZE) {
+            if (VERBOSE >= 1) {
+                printf("WARN: out-of-bounds memory read @0x%08x\n", addr | 0x80000000);
+            }
+            return 0;
+        }
 
-    return cpu->mem[addr];
+        return cpu->mem[addr];
+    }
 }
 
 uint mem_get_byte(cpu_t *cpu, uint addr) {
@@ -117,91 +134,112 @@ uint mem_get_word(cpu_t *cpu, uint addr) {
         ((uint32_t)mem_get_byte(cpu, addr + 3) << 24);
 }
 
+extern uint read_csr_raw(cpu_t *cpu, uint address);
+extern void write_csr_raw(cpu_t *cpu, uint address, uint value);
+extern const uint CSR_MIP, MIP_MTIP, MIP_STIP;
+
 void mem_set_byte(cpu_t *cpu, uint addr, uint val) {
     if (VERBOSE >= 3)
         printf("mem_set_byte(%08x, %08x)\n", addr, val);
 
-    switch (addr) {
-        // CLINT
-        case 0x02000000: cpu->clint.msip = (val & 1) != 0; return;
-        case 0x02000001: return;
-        case 0x02000002: return;
-        case 0x02000003: return;
-
-        case 0x02004000: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 0)) | (val << 0); return;
-        case 0x02004001: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 8)) | (val << 8); return;
-        case 0x02004002: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 16)) | (val << 16); return;
-        case 0x02004003: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 24)) | (val << 24); return;
-        case 0x02004004: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 0)) | (val << 0); return;
-        case 0x02004005: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 8)) | (val << 8); return;
-        case 0x02004006: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 16)) | (val << 16); return;
-        case 0x02004007: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 24)) | (val << 24); return;
-
-        case 0x0200bff8: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 0)) | (val << 0); return;
-        case 0x0200bff9: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 8)) | (val << 8); return;
-        case 0x0200bffa: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 16)) | (val << 16); return;
-        case 0x0200bffb: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 24)) | (val << 24); return;
-        case 0x0200bffc: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 0)) | (val << 0); return;
-        case 0x0200bffd: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 8)) | (val << 8); return;
-        case 0x0200bffe: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 16)) | (val << 16); return;
-        case 0x0200bfff: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 24)) | (val << 24); return;
-
-        // UART (first has rbr_thr_ier_iir, second has lcr_mcr_lsr_scr)
-        case 0x10000000:
-            if ((UART_GET2(LCR) >> 7) == 0) {
-                UART_SET1(THR, val);
-                UART_SET2(LSR, (UART_GET2(LSR) & ~LSR_THR_EMPTY));
-                uart_update_iir(cpu);
-            }
-            return;
-        case 0x10000001:
-            if (UART_GET2(LCR) >> 7 == 0) {
-                if ((UART_GET1(IER) & IER_THREINT_BIT) == 0 &&
-                    (val & IER_THREINT_BIT) != 0 &&
-                    UART_GET1(THR) == 0)
-                {
-                    cpu->uart.thre_ip = true;
-                }
-                UART_SET1(IER, val);
-                uart_update_iir(cpu);
-            }
-            return;
-        case 0x10000003: UART_SET2(LCR, val); return;
-        case 0x10000004: UART_SET2(MCR, val); return;
-        case 0x10000007: UART_SET2(SCR, val); return;
-
-        /* case 0x80001000: printf("%c", (unsigned char)val); return; */
-        /* case 0x80001001: return; */
-        /* case 0x80001002: return; */
-        /* case 0x80001003: return; */
-        /* case 0x80001004: return; */
-        /* case 0x80001005: return; */
-        /* case 0x80001006: return; */
-        /* case 0x80001007: return; */
-        /* case 0x80001040: return; */
-        /* case 0x80001041: return; */
-        /* case 0x80001042: return; */
-        /* case 0x80001043: return; */
-        /* case 0x80001044: return; */
-        /* case 0x80001045: return; */
-        /* case 0x80001046: return; */
-        /* case 0x80001047: return; */
-    }
-
     if ((addr & 0x80000000) == 0) {
-        return;
+        if (addr >= 0x11000000 && addr < 0x11001000) {
-    }
+            if (VERBOSE >= 3)
-
+                printf("NETTX write @%08x/%04x = %08x\n", addr, addr - 0x11001000, val);
-    const int MEM_SIZE = 1024 * 1024 * 128;
+            cpu->net.nettx[addr - 0x11000000] = val;
-
+            return;
-    addr = addr & 0x7FFFFFFF;
-    if (addr >= MEM_SIZE) {
-        if (VERBOSE >= 1) {
-            printf("WARN: out-of-bounds memory write @0x%08x\n", addr | 0x80000000);
         }
-        return;
+
+        // RTC, see device tree
+        if (addr >= 0x03000000 && addr < (0x03000000 + 0x800)) {
+            rtc_write(cpu, addr - 0x03000000, val);
+            return;
+        }
+
+        // MTIP (machine timer interrupt pending) resets when mtimecmp is written
+        if (addr >= 0x02004000 && addr < 0x02004004) {
+            uint cur_mip = read_csr_raw(cpu, CSR_MIP);
+            write_csr_raw(cpu, CSR_MIP, cur_mip & ~(MIP_MTIP | MIP_STIP));
+        }
+
+        switch (addr) {
+            // CLINT
+            case 0x02000000: cpu->clint.msip = (val & 1) != 0; return;
+            case 0x02000001: return;
+            case 0x02000002: return;
+            case 0x02000003: return;
+
+            case 0x02004000: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 0)) | (val << 0); return;
+            case 0x02004001: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 8)) | (val << 8); return;
+            case 0x02004002: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 16)) | (val << 16); return;
+            case 0x02004003: cpu->clint.mtimecmp_lo = (cpu->clint.mtimecmp_lo & ~(0xff << 24)) | (val << 24); return;
+            case 0x02004004: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 0)) | (val << 0); return;
+            case 0x02004005: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 8)) | (val << 8); return;
+            case 0x02004006: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 16)) | (val << 16); return;
+            case 0x02004007: cpu->clint.mtimecmp_hi = (cpu->clint.mtimecmp_hi & ~(0xff << 24)) | (val << 24); return;
+
+            case 0x0200bff8: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 0)) | (val << 0); return;
+            case 0x0200bff9: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 8)) | (val << 8); return;
+            case 0x0200bffa: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 16)) | (val << 16); return;
+            case 0x0200bffb: cpu->clint.mtime_lo = (cpu->clint.mtime_lo & ~(0xff << 24)) | (val << 24); return;
+            case 0x0200bffc: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 0)) | (val << 0); return;
+            case 0x0200bffd: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 8)) | (val << 8); return;
+            case 0x0200bffe: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 16)) | (val << 16); return;
+            case 0x0200bfff: cpu->clint.mtime_hi = (cpu->clint.mtime_hi & ~(0xff << 24)) | (val << 24); return;
+
+            // UART (first has rbr_thr_ier_iir, second has lcr_mcr_lsr_scr)
+            case 0x10000000:
+                if ((UART_GET2(LCR) >> 7) == 0) {
+                    UART_SET1(THR, val);
+                    UART_SET2(LSR, (UART_GET2(LSR) & ~LSR_THR_EMPTY));
+                    uart_update_iir(cpu);
+                }
+                return;
+            case 0x10000001:
+                if (UART_GET2(LCR) >> 7 == 0) {
+                    if ((UART_GET1(IER) & IER_THREINT_BIT) == 0 &&
+                        (val & IER_THREINT_BIT) != 0 &&
+                        UART_GET1(THR) == 0)
+                    {
+                        cpu->uart.thre_ip = true;
+                    }
+                    UART_SET1(IER, val);
+                    uart_update_iir(cpu);
+                }
+                return;
+            case 0x10000003: UART_SET2(LCR, val); return;
+            case 0x10000004: UART_SET2(MCR, val); return;
+            case 0x10000007: UART_SET2(SCR, val); return;
+
+            /* case 0x80001000: printf("%c", (unsigned char)val); return; */
+            /* case 0x80001001: return; */
+            /* case 0x80001002: return; */
+            /* case 0x80001003: return; */
+            /* case 0x80001004: return; */
+            /* case 0x80001005: return; */
+            /* case 0x80001006: return; */
+            /* case 0x80001007: return; */
+            /* case 0x80001040: return; */
+            /* case 0x80001041: return; */
+            /* case 0x80001042: return; */
+            /* case 0x80001043: return; */
+            /* case 0x80001044: return; */
+            /* case 0x80001045: return; */
+            /* case 0x80001046: return; */
+            /* case 0x80001047: return; */
+        }
+    } else {
+        const int MEM_SIZE = 1024 * 1024 * 128;
+
+        addr = addr & 0x7FFFFFFF;
+        if (addr >= MEM_SIZE) {
+            if (VERBOSE >= 1) {
+                printf("WARN: out-of-bounds memory write @0x%08x\n", addr | 0x80000000);
+            }
+            return;
+        }
+        cpu->mem[addr] = val;
     }
-    cpu->mem[addr] = val;
 }
 
 void mem_set_half_word(cpu_t *cpu, uint addr, uint val) {

src/net.h

@@ -0,0 +1,223 @@
+#ifndef NET_H
+#define NET_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+#include <poll.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include "types.h"
+
+static int net_fd = -1;
+static int net_fd_conn = -1;
+static bool g_server;
+
+static struct {
+    union {
+        int32_t i32;
+        uint8_t buf[4];
+    } len;
+    uint32_t i;
+
+    uint8_t *buf;
+    uint32_t buf_pos;
+
+    bool valid;
+    int reads;
+} recv_info;
+
+bool is_server() {
+    return g_server;
+}
+
+void net_init(char *path, bool server)
+{
+    struct sockaddr_un addr;
+    int flags;
+
+    recv_info.len.i32 = -1;
+    recv_info.valid = false;
+    g_server = server;
+
+    if (strlen(path) > sizeof(addr.sun_path) - 1) {
+        perror("path too long");
+        exit(1);
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    strncpy(addr.sun_path, path, sizeof(addr.sun_path) - 1);
+
+    if (server) {
+        net_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+        if (net_fd < 0) {
+            perror("socket");
+            exit(1);
+        }
+
+        if (unlink(path) == -1 && errno != ENOENT) {
+            perror("unlink");
+        }
+
+        if (bind(net_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+            perror("bind");
+            exit(1);
+        }
+
+        if (listen(net_fd, 1) < 0) {
+            perror("listen");
+            exit(1);
+        }
+
+        printf("waiting for net client on %s\n", path);
+        net_fd_conn = accept(net_fd, NULL, NULL);
+        printf("net client connected\n");
+    } else {
+        net_fd = socket(AF_UNIX, SOCK_STREAM, 0);
+        if (net_fd < 0) {
+            perror("socket");
+            exit(1);
+        }
+
+        printf("connecting to net server on %s\n", path);
+
+        if (connect(net_fd, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+            perror("connect");
+            exit(1);
+        }
+
+        printf("net client connected\n");
+        net_fd_conn = net_fd;
+    }
+
+    flags = fcntl(net_fd_conn, F_GETFL, 0);
+    fcntl(net_fd_conn, F_SETFL, flags | O_NONBLOCK);
+}
+
+#define min(a, b) ((a) < (b) ? (a) : (b))
+static void pkt_hex_dump(uint8_t *data, size_t len)
+{
+    int rowsize = 16;
+    int i, l, linelen, remaining;
+    int li = 0;
+    uint8_t ch;
+
+    remaining = len;
+    for (i = 0; i < len; i += rowsize) {
+        printf("%06d\t", li);
+
+        linelen = min(remaining, rowsize);
+        remaining -= rowsize;
+
+        for (l = 0; l < linelen; l++) {
+            ch = data[l];
+            printf("%02X ", (uint32_t) ch);
+        }
+
+        data += linelen;
+        li += 10;
+
+        printf("\n");
+    }
+}
+
+void net_send(uint8_t *data, uint32_t len)
+{
+    if (VERBOSE >= 1)
+        printf("net_send: %d\n", len);
+    if (net_fd_conn != -1) {
+        for (uint32_t i = 0; i < 4; i++) {
+            uint8_t data = (len >> (i * 8)) & 0xFF;
+            if (write(net_fd_conn, &data, 1) < 0) {
+                fprintf(stderr, "net_send: write error (length %d): %s\n", i, strerror(errno));
+                exit(1);
+            }
+        }
+        if (VERBOSE >= 3)
+            pkt_hex_dump(data, len);
+        if (write(net_fd_conn, data, len) != len) {
+            fprintf(stderr, "net_send: write error (data): %s\n", strerror(errno));
+            exit(1);
+        }
+    }
+}
+
+bool net_recv(uint8_t **data_out, uint32_t *len_out) {
+    int data_read;
+
+    if (net_fd_conn == -1) {
+        return false;
+    }
+
+    if (!recv_info.valid) {
+        // read length
+        for (; recv_info.i < 4; recv_info.i++) {
+            uint8_t data;
+            if ((data_read = read(net_fd_conn, &data, 1)) <= 0) {
+                if (data_read == 0 && recv_info.i == 0) {
+                    // no data waiting
+                    return false;
+                }
+                // we're in the middle of reading the length, the rest should
+                // arrive shortly
+                if (data_read != 0 && errno != EAGAIN) {
+                    fprintf(stderr, "net_recv: read error (at byte %d): %s\n", recv_info.i, strerror(errno));
+                    exit(1);
+                }
+                // next emulation loop will retry
+                return false;
+            }
+            recv_info.len.buf[recv_info.i] = data;
+        }
+        // length received, prime for receiving data
+        if (VERBOSE >= 1)
+            printf("net_recv: awaiting %d\n", recv_info.len.i32);
+        recv_info.i = 0;
+        recv_info.buf = malloc(recv_info.len.i32);
+        if (recv_info.buf == NULL) {
+            fprintf(stderr, "net_recv: malloc error\n");
+            exit(1);
+        }
+        recv_info.valid = true;
+    }
+
+    // read data
+    if ((data_read = read(net_fd_conn, recv_info.buf + recv_info.buf_pos, recv_info.len.i32 - recv_info.buf_pos)) < 0) {
+        if (errno != EAGAIN) {
+            fprintf(stderr, "net_recv: read error (data): %s\n", strerror(errno));
+            exit(1);
+        }
+        // next emulation loop will retry
+        return false;
+    }
+
+    recv_info.reads++;
+
+    recv_info.buf_pos += data_read;
+    if (recv_info.buf_pos == recv_info.len.i32) {
+        // full data packet received, return it
+        if (VERBOSE >= 1)
+            printf("net_recv: got %d in %d\n", recv_info.len.i32, recv_info.reads);
+        if (VERBOSE >= 3)
+            pkt_hex_dump(recv_info.buf, recv_info.len.i32);
+        *data_out = recv_info.buf;
+        *len_out = (uint32_t)recv_info.len.i32;
+        recv_info.reads = 0;
+        recv_info.buf_pos = 0;
+        recv_info.len.i32 = 0;
+        recv_info.valid = false;
+        return true;
+    }
+
+    // still some data left
+    return false;
+}
+
+#endif

src/rtc.h

@@ -0,0 +1,73 @@
+#ifndef RTC_H
+#define RTC_H
+
+#include <stdio.h>
+#include <time.h>
+#include "types.h"
+
+// Defines taken from ds1742 linux kernel driver
+#define bcd2bin(x) (((x) & 0x0f) + ((x) >> 4) * 10)
+#define bin2bcd(x) ((((x) / 10) << 4) + (x) % 10)
+
+
+#define RTC_SIZE           8
+#define RTC_ADDRESS        (0x800 - RTC_SIZE)
+
+#define RTC_CONTROL        (0 + RTC_ADDRESS)
+#define RTC_CENTURY        (0 + RTC_ADDRESS)
+#define RTC_SECONDS        (1 + RTC_ADDRESS)
+#define RTC_MINUTES        (2 + RTC_ADDRESS)
+#define RTC_HOURS          (3 + RTC_ADDRESS)
+#define RTC_DAY            (4 + RTC_ADDRESS)
+#define RTC_DATE           (5 + RTC_ADDRESS)
+#define RTC_MONTH          (6 + RTC_ADDRESS)
+#define RTC_YEAR           (7 + RTC_ADDRESS)
+
+#define RTC_CENTURY_MASK    0x3f
+#define RTC_SECONDS_MASK    0x7f
+#define RTC_DAY_MASK        0x07
+
+/* Bits in the Control/Century register */
+#define RTC_WRITE        0x80
+#define RTC_READ        0x40
+
+/* Bits in the Seconds register */
+#define RTC_STOP        0x80
+
+/* Bits in the Day register */
+#define RTC_BATT_FLAG        0x80
+
+uint8_t rtc_read(cpu_t *cpu, uint32_t offset) {
+    offset -= RTC_ADDRESS;
+    if (offset > 3) {
+        return (cpu->rtc1 >> ((offset - 4) * 8)) & 0xff;
+    }
+    return (cpu->rtc0 >> (offset * 8)) & 0xff;
+}
+
+void rtc_write(cpu_t *cpu, uint32_t offset, uint8_t data) {
+    switch (offset) {
+        case RTC_CONTROL:
+            if (data == RTC_READ) {
+                if (VERBOSE >= 1)
+                    printf("RTC update!\n");
+                // Get real time from host
+                struct timespec ts;
+                clock_gettime(CLOCK_REALTIME, &ts);
+                struct tm *t = localtime(&ts.tv_sec);
+                cpu->rtc0 =
+                    bin2bcd((t->tm_year + 1900) / 100) |
+                    bin2bcd(t->tm_sec) << 8 |
+                    bin2bcd(t->tm_min) << 16 |
+                    bin2bcd(t->tm_hour) << 24;
+                cpu->rtc1 =
+                    bin2bcd(t->tm_wday) |
+                    bin2bcd(t->tm_mday) << 8 |
+                    bin2bcd(t->tm_mon + 1) << 16 |
+                    bin2bcd(t->tm_year % 100) << 24;
+            }
+            break;
+    }
+}
+
+#endif

src/trap.h

@@ -45,8 +45,7 @@ const uint MIP_ALL = MIP_MEIP | MIP_MTIP | MIP_MSIP | MIP_SEIP | MIP_STIP | MIP_
 #include "csr.h"
 
 // returns true if IRQ was handled or !is_interrupt
-bool handle_trap(cpu_t *cpu, ins_ret *ret, bool is_interrupt) {
+bool handle_trap(cpu_t *cpu, ins_ret *ret, trap t, bool is_interrupt) {
-    trap t = ret->trap;
     uint current_privilege = cpu->csr.privilege;
 
     uint mdeleg = read_csr_raw(cpu, is_interrupt ? CSR_MIDELEG : CSR_MEDELEG);
@@ -131,6 +130,8 @@ bool handle_trap(cpu_t *cpu, ins_ret *ret, bool is_interrupt) {
     }
 
     // NOTE: No user mode interrupt/exception handling!
+    // Importantly, this clears xIE in mstatus, so even if MIP isn't cleared,
+    // the interrupt will not be immediately reentrant.
     if (new_privilege == PRIV_MACHINE) {
         uint mie = (mstatus >> 3) & 1;
         uint new_status = (mstatus & ~0x1888) | (mie << 7) | (current_privilege << 11);
@@ -141,37 +142,39 @@ bool handle_trap(cpu_t *cpu, ins_ret *ret, bool is_interrupt) {
         write_csr_raw(cpu, CSR_SSTATUS, new_status);
     }
 
-    if (VERBOSE >= (is_interrupt ? 1 : 2))
+    if (VERBOSE >= (is_interrupt && t.type != trap_MachineTimerInterrupt && t.type != trap_SupervisorTimerInterrupt ? 1 : 2))
         printf("trap: type=%08x value=%08x (IRQ: %d) moved PC from @%08x (#%d) to @%08x (#%d)\n", t.type, t.value, is_interrupt, cpu->pc, current_privilege, ret->pc_val, new_privilege);
 
     return true;
 }
 
 void handle_irq_and_trap(cpu_t *cpu, ins_ret *ret) {
-    bool trap = ret->trap.en;
+    trap t = ret->trap;
     uint mip_reset = MIP_ALL;
     uint cur_mip = read_csr_raw(cpu, CSR_MIP);
+    bool irq = false;
 
-    if (!trap) {
+    if (!t.en) {
+        irq = true;
         uint mirq = cur_mip & read_csr_raw(cpu, CSR_MIE);
-#define HANDLE(mip, ttype) case mip: mip_reset = mip; ret->trap.en = true; ret->trap.type = ttype; break;
+        if (false) {}
-        switch (mirq & MIP_ALL) {
+#define HANDLE(mip, ttype) else if (mirq & mip) { mip_reset = mip; t.en = true; t.type = ttype; }
-            HANDLE(MIP_MEIP, trap_MachineExternalInterrupt)
+        HANDLE(MIP_MEIP, trap_MachineExternalInterrupt)
-            HANDLE(MIP_MSIP, trap_MachineSoftwareInterrupt)
+        HANDLE(MIP_MSIP, trap_MachineSoftwareInterrupt)
-            HANDLE(MIP_MTIP, trap_MachineTimerInterrupt)
+        HANDLE(MIP_MTIP, trap_MachineTimerInterrupt)
-            HANDLE(MIP_SEIP, trap_SupervisorExternalInterrupt)
+        HANDLE(MIP_SEIP, trap_SupervisorExternalInterrupt)
-            HANDLE(MIP_SSIP, trap_SupervisorSoftwareInterrupt)
+        HANDLE(MIP_SSIP, trap_SupervisorSoftwareInterrupt)
-            HANDLE(MIP_STIP, trap_SupervisorTimerInterrupt)
+        HANDLE(MIP_STIP, trap_SupervisorTimerInterrupt)
-        }
 #undef HANDLE
     }
 
-    bool irq = mip_reset != MIP_ALL;
+    if (t.en) {
-    if (trap || irq) {
+        bool handled = handle_trap(cpu, ret, t, irq);
-        bool handled = handle_trap(cpu, ret, irq);
         if (handled && irq) {
-            // reset MIP value since IRQ was handled
+            // reset MIP value if IRQ other than timer was handled
-            write_csr_raw(cpu, CSR_MIP, cur_mip & ~mip_reset);
+            // (MTIP/STIP will be reset by write to mtimecmp)
+            if ((mip_reset & 0x0A0) == 0)
+                write_csr_raw(cpu, CSR_MIP, cur_mip & ~mip_reset);
             if (VERBOSE >= 3)
                 printf("IRQ handled: old_mip=%03x new_mip=%03x\n", cur_mip, read_csr_raw(cpu, CSR_MIP));
         }

src/types.h

@@ -11,6 +11,8 @@ static bool SINGLE_STEP = false;
 typedef uint32_t uint;
 typedef uint32_t uint;
 
+static float _Time;
+
 typedef struct {
     uint data[4096];
     uint privilege;
@@ -36,6 +38,12 @@ typedef struct {
     uint ppn;
 } mmu_state;
 
+typedef struct {
+    uint rx_ready;
+    uint8_t *nettx;
+    uint8_t *netrx;
+} net_state;
+
 typedef struct {
     uint clock;
     uint xreg[32];
@@ -48,6 +56,10 @@ typedef struct {
     clint_state clint;
     uart_state uart;
     mmu_state mmu;
+    net_state net;
+
+    uint rtc0, rtc1;
+    float start_time_ref;
 
     bool reservation_en;
     uint reservation_addr;

test.c

@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+#define OFFSET_UINT2_POS(x, y, w, h, n) uint2((x + n) % w, y + ((n + x) / h))
+#define RAM_L1_ARRAY_IDX(a) (((a >> 2) & 127) | (((a >> 11) & 0x3) << 7))
+
+void uint2(int x, int y) {
+    printf("x=%d y=%d\n", x, y);
+}
+
+int main() {
+    OFFSET_UINT2_POS(20, 0, 128, 128, 10);
+    OFFSET_UINT2_POS(120, 0, 128, 128, 10);
+    OFFSET_UINT2_POS(20, 3, 128, 128, 140);
+    OFFSET_UINT2_POS(120, 0, 128, 128, (128*8 + 4));
+
+    printf("\n");
+
+    for (unsigned int i = 0; i < 128*128*16; i+=4) {
+        printf("%03d: %d\n", i/4, RAM_L1_ARRAY_IDX(i));
+    }
+
+    return 0;
+}

toimg/src/main.rs

@@ -113,8 +113,8 @@ fn main() {
 
     let y = idx / width;
     println!("Saving result... (required size: x={} y={})", width, y + 1);
-    fr.save(input.clone().with_extension("r.bmp")).unwrap();
+    fr.save(input.clone().with_extension("r.png")).unwrap();
-    fg.save(input.clone().with_extension("g.bmp")).unwrap();
+    fg.save(input.clone().with_extension("g.png")).unwrap();
-    fb.save(input.clone().with_extension("b.bmp")).unwrap();
+    fb.save(input.clone().with_extension("b.png")).unwrap();
-    fa.save(input.clone().with_extension("a.bmp")).unwrap();
+    fa.save(input.clone().with_extension("a.png")).unwrap();
 }