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linux/arch/xtensa/lib/memcopy.S
Max Filippov d6d5f19e21 xtensa: abstract 'entry' and 'retw' in assembly code 
Provide abi_entry, abi_entry_default, abi_ret and abi_ret_default macros
that allocate aligned stack frame in windowed and call0 ABIs.
Provide XTENSA_SPILL_STACK_RESERVE macro that specifies required stack
frame size when register spilling is involved.
Replace all uses of 'entry' and 'retw' with the above macros.
This makes most of the xtensa assembly code ready for XEA3 and call0 ABI.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
2019-07-08 10:04:48 -07:00

554 lines
12 KiB
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/*
* arch/xtensa/lib/hal/memcopy.S -- Core HAL library functions
* xthal_memcpy and xthal_bcopy
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2002 - 2012 Tensilica Inc.
*/
#include <linux/linkage.h>
#include <asm/asmmacro.h>
#include <asm/core.h>
/*
* void *memcpy(void *dst, const void *src, size_t len);
*
* This function is intended to do the same thing as the standard
* library function memcpy() for most cases.
* However, where the source and/or destination references
* an instruction RAM or ROM or a data RAM or ROM, that
* source and/or destination will always be accessed with
* 32-bit load and store instructions (as required for these
* types of devices).
*
* !!!!!!! XTFIXME:
* !!!!!!! Handling of IRAM/IROM has not yet
* !!!!!!! been implemented.
*
* The (general case) algorithm is as follows:
* If destination is unaligned, align it by conditionally
* copying 1 and 2 bytes.
* If source is aligned,
* do 16 bytes with a loop, and then finish up with
* 8, 4, 2, and 1 byte copies conditional on the length;
* else (if source is unaligned),
* do the same, but use SRC to align the source data.
* This code tries to use fall-through branches for the common
* case of aligned source and destination and multiple
* of 4 (or 8) length.
*
* Register use:
* a0/ return address
* a1/ stack pointer
* a2/ return value
* a3/ src
* a4/ length
* a5/ dst
* a6/ tmp
* a7/ tmp
* a8/ tmp
* a9/ tmp
* a10/ tmp
* a11/ tmp
*/
.text
/*
* Byte by byte copy
*/
.align 4
.byte 0 # 1 mod 4 alignment for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lbytecopy:
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lbytecopydone
#else /* !XCHAL_HAVE_LOOPS */
beqz a4, .Lbytecopydone
add a7, a3, a4 # a7 = end address for source
#endif /* !XCHAL_HAVE_LOOPS */
.Lnextbyte:
l8ui a6, a3, 0
addi a3, a3, 1
s8i a6, a5, 0
addi a5, a5, 1
#if !XCHAL_HAVE_LOOPS
bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Lbytecopydone:
abi_ret_default
/*
* Destination is unaligned
*/
.align 4
.Ldst1mod2: # dst is only byte aligned
_bltui a4, 7, .Lbytecopy # do short copies byte by byte
# copy 1 byte
l8ui a6, a3, 0
addi a3, a3, 1
addi a4, a4, -1
s8i a6, a5, 0
addi a5, a5, 1
_bbci.l a5, 1, .Ldstaligned # if dst is now aligned, then
# return to main algorithm
.Ldst2mod4: # dst 16-bit aligned
# copy 2 bytes
_bltui a4, 6, .Lbytecopy # do short copies byte by byte
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a3, a3, 2
addi a4, a4, -2
s8i a6, a5, 0
s8i a7, a5, 1
addi a5, a5, 2
j .Ldstaligned # dst is now aligned, return to main algorithm
ENTRY(__memcpy)
WEAK(memcpy)
abi_entry_default
# a2/ dst, a3/ src, a4/ len
mov a5, a2 # copy dst so that a2 is return value
.Lcommon:
_bbsi.l a2, 0, .Ldst1mod2 # if dst is 1 mod 2
_bbsi.l a2, 1, .Ldst2mod4 # if dst is 2 mod 4
.Ldstaligned: # return here from .Ldst?mod? once dst is aligned
srli a7, a4, 4 # number of loop iterations with 16B
# per iteration
movi a8, 3 # if source is not aligned,
_bany a3, a8, .Lsrcunaligned # then use shifting copy
/*
* Destination and source are word-aligned, use word copy.
*/
# copy 16 bytes per iteration for word-aligned dst and word-aligned src
#if XCHAL_HAVE_LOOPS
loopnez a7, .Loop1done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop1done
slli a8, a7, 4
add a8, a8, a3 # a8 = end of last 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1:
l32i a6, a3, 0
l32i a7, a3, 4
s32i a6, a5, 0
l32i a6, a3, 8
s32i a7, a5, 4
l32i a7, a3, 12
s32i a6, a5, 8
addi a3, a3, 16
s32i a7, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1done:
bbci.l a4, 3, .L2
# copy 8 bytes
l32i a6, a3, 0
l32i a7, a3, 4
addi a3, a3, 8
s32i a6, a5, 0
s32i a7, a5, 4
addi a5, a5, 8
.L2:
bbsi.l a4, 2, .L3
bbsi.l a4, 1, .L4
bbsi.l a4, 0, .L5
abi_ret_default
.L3:
# copy 4 bytes
l32i a6, a3, 0
addi a3, a3, 4
s32i a6, a5, 0
addi a5, a5, 4
bbsi.l a4, 1, .L4
bbsi.l a4, 0, .L5
abi_ret_default
.L4:
# copy 2 bytes
l16ui a6, a3, 0
addi a3, a3, 2
s16i a6, a5, 0
addi a5, a5, 2
bbsi.l a4, 0, .L5
abi_ret_default
.L5:
# copy 1 byte
l8ui a6, a3, 0
s8i a6, a5, 0
abi_ret_default
/*
* Destination is aligned, Source is unaligned
*/
.align 4
.Lsrcunaligned:
_beqz a4, .Ldone # avoid loading anything for zero-length copies
# copy 16 bytes per iteration for word-aligned dst and unaligned src
__ssa8 a3 # set shift amount from byte offset
/* set to 1 when running on ISS (simulator) with the
lint or ferret client, or 0 to save a few cycles */
#define SIM_CHECKS_ALIGNMENT 1
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
and a11, a3, a8 # save unalignment offset for below
sub a3, a3, a11 # align a3
#endif
l32i a6, a3, 0 # load first word
#if XCHAL_HAVE_LOOPS
loopnez a7, .Loop2done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop2done
slli a10, a7, 4
add a10, a10, a3 # a10 = end of last 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2:
l32i a7, a3, 4
l32i a8, a3, 8
__src_b a6, a6, a7
s32i a6, a5, 0
l32i a9, a3, 12
__src_b a7, a7, a8
s32i a7, a5, 4
l32i a6, a3, 16
__src_b a8, a8, a9
s32i a8, a5, 8
addi a3, a3, 16
__src_b a9, a9, a6
s32i a9, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2done:
bbci.l a4, 3, .L12
# copy 8 bytes
l32i a7, a3, 4
l32i a8, a3, 8
__src_b a6, a6, a7
s32i a6, a5, 0
addi a3, a3, 8
__src_b a7, a7, a8
s32i a7, a5, 4
addi a5, a5, 8
mov a6, a8
.L12:
bbci.l a4, 2, .L13
# copy 4 bytes
l32i a7, a3, 4
addi a3, a3, 4
__src_b a6, a6, a7
s32i a6, a5, 0
addi a5, a5, 4
mov a6, a7
.L13:
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
add a3, a3, a11 # readjust a3 with correct misalignment
#endif
bbsi.l a4, 1, .L14
bbsi.l a4, 0, .L15
.Ldone: abi_ret_default
.L14:
# copy 2 bytes
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a3, a3, 2
s8i a6, a5, 0
s8i a7, a5, 1
addi a5, a5, 2
bbsi.l a4, 0, .L15
abi_ret_default
.L15:
# copy 1 byte
l8ui a6, a3, 0
s8i a6, a5, 0
abi_ret_default
ENDPROC(__memcpy)
/*
* void bcopy(const void *src, void *dest, size_t n);
*/
ENTRY(bcopy)
abi_entry_default
# a2=src, a3=dst, a4=len
mov a5, a3
mov a3, a2
mov a2, a5
j .Lmovecommon # go to common code for memmove+bcopy
ENDPROC(bcopy)
/*
* void *memmove(void *dst, const void *src, size_t len);
*
* This function is intended to do the same thing as the standard
* library function memmove() for most cases.
* However, where the source and/or destination references
* an instruction RAM or ROM or a data RAM or ROM, that
* source and/or destination will always be accessed with
* 32-bit load and store instructions (as required for these
* types of devices).
*
* !!!!!!! XTFIXME:
* !!!!!!! Handling of IRAM/IROM has not yet
* !!!!!!! been implemented.
*
* The (general case) algorithm is as follows:
* If end of source doesn't overlap destination then use memcpy.
* Otherwise do memcpy backwards.
*
* Register use:
* a0/ return address
* a1/ stack pointer
* a2/ return value
* a3/ src
* a4/ length
* a5/ dst
* a6/ tmp
* a7/ tmp
* a8/ tmp
* a9/ tmp
* a10/ tmp
* a11/ tmp
*/
/*
* Byte by byte copy
*/
.align 4
.byte 0 # 1 mod 4 alignment for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lbackbytecopy:
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lbackbytecopydone
#else /* !XCHAL_HAVE_LOOPS */
beqz a4, .Lbackbytecopydone
sub a7, a3, a4 # a7 = start address for source
#endif /* !XCHAL_HAVE_LOOPS */
.Lbacknextbyte:
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a7, .Lbacknextbyte # continue loop if
# $a3:src != $a7:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.Lbackbytecopydone:
abi_ret_default
/*
* Destination is unaligned
*/
.align 4
.Lbackdst1mod2: # dst is only byte aligned
_bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
# copy 1 byte
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
addi a4, a4, -1
_bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
# return to main algorithm
.Lbackdst2mod4: # dst 16-bit aligned
# copy 2 bytes
_bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
addi a3, a3, -2
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a5, a5, -2
s8i a6, a5, 0
s8i a7, a5, 1
addi a4, a4, -2
j .Lbackdstaligned # dst is now aligned,
# return to main algorithm
ENTRY(__memmove)
WEAK(memmove)
abi_entry_default
# a2/ dst, a3/ src, a4/ len
mov a5, a2 # copy dst so that a2 is return value
.Lmovecommon:
sub a6, a5, a3
bgeu a6, a4, .Lcommon
add a5, a5, a4
add a3, a3, a4
_bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
_bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
.Lbackdstaligned: # return here from .Lbackdst?mod? once dst is aligned
srli a7, a4, 4 # number of loop iterations with 16B
# per iteration
movi a8, 3 # if source is not aligned,
_bany a3, a8, .Lbacksrcunaligned # then use shifting copy
/*
* Destination and source are word-aligned, use word copy.
*/
# copy 16 bytes per iteration for word-aligned dst and word-aligned src
#if XCHAL_HAVE_LOOPS
loopnez a7, .backLoop1done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .backLoop1done
slli a8, a7, 4
sub a8, a3, a8 # a8 = start of first 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop1:
addi a3, a3, -16
l32i a7, a3, 12
l32i a6, a3, 8
addi a5, a5, -16
s32i a7, a5, 12
l32i a7, a3, 4
s32i a6, a5, 8
l32i a6, a3, 0
s32i a7, a5, 4
s32i a6, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a8, .backLoop1 # continue loop if a3:src != a8:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop1done:
bbci.l a4, 3, .Lback2
# copy 8 bytes
addi a3, a3, -8
l32i a6, a3, 0
l32i a7, a3, 4
addi a5, a5, -8
s32i a6, a5, 0
s32i a7, a5, 4
.Lback2:
bbsi.l a4, 2, .Lback3
bbsi.l a4, 1, .Lback4
bbsi.l a4, 0, .Lback5
abi_ret_default
.Lback3:
# copy 4 bytes
addi a3, a3, -4
l32i a6, a3, 0
addi a5, a5, -4
s32i a6, a5, 0
bbsi.l a4, 1, .Lback4
bbsi.l a4, 0, .Lback5
abi_ret_default
.Lback4:
# copy 2 bytes
addi a3, a3, -2
l16ui a6, a3, 0
addi a5, a5, -2
s16i a6, a5, 0
bbsi.l a4, 0, .Lback5
abi_ret_default
.Lback5:
# copy 1 byte
addi a3, a3, -1
l8ui a6, a3, 0
addi a5, a5, -1
s8i a6, a5, 0
abi_ret_default
/*
* Destination is aligned, Source is unaligned
*/
.align 4
.Lbacksrcunaligned:
_beqz a4, .Lbackdone # avoid loading anything for zero-length copies
# copy 16 bytes per iteration for word-aligned dst and unaligned src
__ssa8 a3 # set shift amount from byte offset
#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS with
* the lint or ferret client, or 0
* to save a few cycles */
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
and a11, a3, a8 # save unalignment offset for below
sub a3, a3, a11 # align a3
#endif
l32i a6, a3, 0 # load first word
#if XCHAL_HAVE_LOOPS
loopnez a7, .backLoop2done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .backLoop2done
slli a10, a7, 4
sub a10, a3, a10 # a10 = start of first 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop2:
addi a3, a3, -16
l32i a7, a3, 12
l32i a8, a3, 8
addi a5, a5, -16
__src_b a6, a7, a6
s32i a6, a5, 12
l32i a9, a3, 4
__src_b a7, a8, a7
s32i a7, a5, 8
l32i a6, a3, 0
__src_b a8, a9, a8
s32i a8, a5, 4
__src_b a9, a6, a9
s32i a9, a5, 0
#if !XCHAL_HAVE_LOOPS
bne a3, a10, .backLoop2 # continue loop if a3:src != a10:src_start
#endif /* !XCHAL_HAVE_LOOPS */
.backLoop2done:
bbci.l a4, 3, .Lback12
# copy 8 bytes
addi a3, a3, -8
l32i a7, a3, 4
l32i a8, a3, 0
addi a5, a5, -8
__src_b a6, a7, a6
s32i a6, a5, 4
__src_b a7, a8, a7
s32i a7, a5, 0
mov a6, a8
.Lback12:
bbci.l a4, 2, .Lback13
# copy 4 bytes
addi a3, a3, -4
l32i a7, a3, 0
addi a5, a5, -4
__src_b a6, a7, a6
s32i a6, a5, 0
mov a6, a7
.Lback13:
#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
add a3, a3, a11 # readjust a3 with correct misalignment
#endif
bbsi.l a4, 1, .Lback14
bbsi.l a4, 0, .Lback15
.Lbackdone:
abi_ret_default
.Lback14:
# copy 2 bytes
addi a3, a3, -2
l8ui a6, a3, 0
l8ui a7, a3, 1
addi a5, a5, -2
s8i a6, a5, 0
s8i a7, a5, 1
bbsi.l a4, 0, .Lback15
abi_ret_default
.Lback15:
# copy 1 byte
addi a3, a3, -1
addi a5, a5, -1
l8ui a6, a3, 0
s8i a6, a5, 0
abi_ret_default
ENDPROC(__memmove)
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