* Patch by Daniel Engstrm, 13 Nov 2002:
Add support for i386 architecture and AMD SC520 board * Patch by Pierre Aubert, 12 Nov 2002: Add support for DOS filesystem and booting from DOS floppy disk
This commit is contained in:
wdenk
443
lib_i386/bios.S
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443
lib_i386/bios.S
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/*
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* (C) Copyright 2002
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* Daniel Engstr<EFBFBD>m, Omicron Ceti AB, daniel@omicron.se
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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/*
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* Based on msbios.c from rolo 1.6:
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*----------------------------------------------------------------------
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* (C) Copyright 2000
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* Sysgo Real-Time Solutions GmbH
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* Klein-Winternheim, Germany
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*----------------------------------------------------------------------
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*/
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/*
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* During it's initialization phase, before switching to protected
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* mode, the Linux Kernel makes a few BIOS calls. This won't work
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* if the board does not have a BIOS.
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*
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* This is a very minimalisic BIOS that supplies just enough
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* functionality to keep the Linux Kernel happy. It is NOT
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* a general purpose replacement for a real BIOS !!
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*/
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#define OFFS_ES 0
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#define OFFS_GS 2
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#define OFFS_DS 4
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#define OFFS_DI 6
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#define OFFS_SI 8
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#define OFFS_BP 10
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#define OFFS_SP 12
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#define OFFS_BX 14
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#define OFFS_DX 16
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#define OFFS_CX 18
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#define OFFS_AX 20
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#define OFFS_VECTOR 22
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#define OFFS_IP 24
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#define OFFS_CS 26
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#define OFFS_FLAGS 28
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#define SEGMENT 0x40
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#define STACK 0x800 /* stack at 0x40:0x800 -> 0x800 */
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.section .bios, "ax"
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.code16
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.org 0
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.globl rm_int00
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rm_int00:
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pushw $0
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jmp any_interrupt16
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.globl rm_int01
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rm_int01:
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pushw $1
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jmp any_interrupt16
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.globl rm_int02
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rm_int02:
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pushw $2
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jmp any_interrupt16
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.globl rm_int03
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rm_int03:
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pushw $3
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jmp any_interrupt16
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.globl rm_int04
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rm_int04:
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pushw $4
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jmp any_interrupt16
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.globl rm_int05
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rm_int05:
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pushw $5
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jmp any_interrupt16
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.globl rm_int06
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rm_int06:
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pushw $6
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jmp any_interrupt16
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.globl rm_int07
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rm_int07:
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pushw $7
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jmp any_interrupt16
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.globl rm_int08
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rm_int08:
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pushw $8
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jmp any_interrupt16
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.globl rm_int09
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rm_int09:
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pushw $9
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jmp any_interrupt16
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.globl rm_int0a
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rm_int0a:
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pushw $10
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jmp any_interrupt16
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.globl rm_int0b
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rm_int0b:
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pushw $11
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jmp any_interrupt16
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.globl rm_int0c
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rm_int0c:
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pushw $12
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jmp any_interrupt16
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.globl rm_int0d
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rm_int0d:
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pushw $13
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jmp any_interrupt16
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.globl rm_int0e
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rm_int0e:
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pushw $14
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jmp any_interrupt16
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.globl rm_int0f
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rm_int0f:
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pushw $15
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jmp any_interrupt16
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.globl rm_int10
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rm_int10:
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pushw $16
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jmp any_interrupt16
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.globl rm_int11
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rm_int11:
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pushw $17
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jmp any_interrupt16
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.globl rm_int12
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rm_int12:
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pushw $18
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jmp any_interrupt16
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.globl rm_int13
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rm_int13:
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pushw $19
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jmp any_interrupt16
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.globl rm_int14
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rm_int14:
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pushw $20
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jmp any_interrupt16
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.globl rm_int15
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rm_int15:
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pushw $21
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jmp any_interrupt16
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.globl rm_int16
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rm_int16:
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pushw $22
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jmp any_interrupt16
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.globl rm_int17
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rm_int17:
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pushw $23
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jmp any_interrupt16
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.globl rm_int18
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rm_int18:
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pushw $24
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jmp any_interrupt16
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.globl rm_int19
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rm_int19:
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pushw $25
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jmp any_interrupt16
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.globl rm_int1a
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rm_int1a:
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pushw $26
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jmp any_interrupt16
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.globl rm_int1b
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rm_int1b:
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pushw $27
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jmp any_interrupt16
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.globl rm_int1c
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rm_int1c:
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pushw $28
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jmp any_interrupt16
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.globl rm_int1d
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rm_int1d:
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pushw $29
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jmp any_interrupt16
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.globl rm_int1e
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rm_int1e:
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pushw $30
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jmp any_interrupt16
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.globl rm_int1f
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rm_int1f:
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pushw $31
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jmp any_interrupt16
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.globl rm_def_int
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rm_def_int:
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iret
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/*
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* All interrupt jumptable entries jump to here
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* after pushing the interrupt vector number onto the
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* stack.
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*/
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any_interrupt16:
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pusha /* save general registers */
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pushw %ds /* save some segments */
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pushw %gs
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pushw %es
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pushw %ss /* save callers stack segment .. */
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popw %gs /* ... in gs */
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movw $SEGMENT,%ax /* setup my segments */
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movw %ax,%ds
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movw %ax,%es
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movw %ax,%ss
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movw %sp,%bp
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movw $STACK,%sp /* setup BIOS stackpointer */
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gs movw OFFS_VECTOR(%bp), %ax
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cmpw $0x10, %ax
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je Lint_10h
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cmpw $0x11, %ax
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je Lint_11h
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cmpw $0x13, %ax
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je Lint_13h
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cmpw $0x15, %ax
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je Lint_15h
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cmpw $0x16, %ax
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je Lint_16h
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movw $0xffff, %ax
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jmp Lout
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Lint_10h: /* VGA BIOS services */
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call bios_10h
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jmp Lout
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Lint_11h:
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call bios_11h
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jmp Lout
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Lint_13h: /* BIOS disk services */
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call bios_13h
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jmp Lout
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Lint_15h: /* Misc. BIOS services */
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call bios_15h
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jmp Lout
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Lint_16h: /* keyboard services */
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call bios_16h
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jmp Lout
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Lout:
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cmpw $0, %ax
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je Lhandeled
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/* Insert code for unhandeled INTs here.
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*
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* ROLO prints a message to the console
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* (we could do that but then we're in 16bit mode
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* so we'll have to get back into 32bit mode
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* to use the console I/O routines (if we do this
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* we shuls make int 0x10 and int 0x16 work as well))
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*/
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Lhandeled:
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pushw %gs /* restore callers stack segment */
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popw %ss
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movw %bp,%sp /* restore stackpointer */
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popw %es /* restore segment selectors */
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popw %gs
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popw %ds
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popa /* restore GP registers */
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addw $2,%sp /* dump vector number */
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iret /* return from interrupt */
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/*
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************************************************************
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* BIOS interrupt 10h -- VGA services
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************************************************************
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*/
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bios_10h:
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gs movw OFFS_AX(%bp), %ax
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shrw $8, %ax
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cmpw $0x3, %ax
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je Lcur_pos
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cmpw $0xf, %ax
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je Lvid_state
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cmpw $0x12, %ax
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je Lvid_cfg
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movw $0xffff, %ax
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ret
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Lcur_pos: /* Read Cursor Position and Size */
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gs movw $0, OFFS_CX(%bp)
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gs movw $0, OFFS_DX(%bp)
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xorw %ax, %ax
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ret
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Lvid_state: /* Get Video State */
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gs movw $(80 << 8|0x03), OFFS_AX(%bp) /* 80 columns, 80x25, 16 colors */
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gs movw $0, OFFS_BX(%bp)
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xorw %ax, %ax
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ret
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Lvid_cfg: /* Video Subsystem Configuration (EGA/VGA) */
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gs movw $0x10, OFFS_BX(%bp) /* indicate CGA/MDA/HGA */
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xorw %ax, %ax
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ret
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/*
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************************************************************
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* BIOS interrupt 11h -- Equipment determination
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************************************************************
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*/
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bios_11h:
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movw bios_equipment, %ax
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gs movw %ax, OFFS_AX(%bp)
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xorw %ax, %ax
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ret
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/*
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************************************************************
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* BIOS interrupt 13h -- Disk services
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************************************************************
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*/
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bios_13h:
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gs movw OFFS_AX(%bp), %ax
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shrw $8, %ax
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cmpw $0x15, %ax
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je Lfunc_15h
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movw $0xffff, %ax
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ret
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Lfunc_15h:
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gs movw OFFS_AX(%bp), %ax
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andw $0xff, %ax /* return AH=0->drive not present */
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gs movw %ax, OFFS_AX(%bp)
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xorw %ax, %ax
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ret
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/*
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***********************************************************
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* BIOS interrupt 15h -- Miscellaneous services
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***********************************************************
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*/
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bios_15h:
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gs movw OFFS_AX(%bp), %ax
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shrw $8, %ax
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cmpw $0xc0, %ax
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je Lfunc_c0h
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cmpw $0xe8, %ax
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je Lfunc_e8h
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cmpw $0x88, %ax
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je Lfunc_88h
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movw $0xffff, %ax
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ret
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Lfunc_c0h: /* Return System Configuration Parameters (PS2 only) */
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gs movw OFFS_FLAGS(%bp), %ax
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orw $1, %ax /* return carry -- function not supported */
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gs movw %ax, OFFS_FLAGS(%bp)
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xorw %ax, %ax
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ret
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Lfunc_e8h:
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gs movw OFFS_AX(%bp), %ax
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andw $0xff, %ax
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cmpw $1, %ax
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je Lfunc_e801h
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gs movw OFFS_FLAGS(%bp), %ax
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orw $1, %ax /* return carry -- function not supported */
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gs movw %ax, OFFS_FLAGS(%bp)
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xorw %ax, %ax
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ret
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Lfunc_e801h: /* Get memory size for >64M Configurations */
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movw $ram_in_64kb_chunks, %ax
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cmpw $256, %ax
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ja Lmore_than_16mb
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shlw $6, %ax /* multiply by 64 */
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gs movw %ax, OFFS_AX(%bp) /* return memory size in 1kb chunks in AX and CX */
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gs movw %ax, OFFS_CX(%bp)
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xorw %ax, %ax
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gs movw %ax, OFFS_BX(%bp) /* set BX and DX to 0*/
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gs movw %ax, OFFS_DX(%bp)
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gs movw OFFS_FLAGS(%bp), %ax
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andw $0xfffe, %ax /* clear carry -- function succeeded */
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gs movw %ax, OFFS_FLAGS(%bp)
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xorw %ax, %ax
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ret
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Lmore_than_16mb:
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subw $0x100, %ax /* subtract 16MB */
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gs movw $0x3c00, OFFS_AX(%bp) /* return 0x3c00 (16MB-384k) in AX and CX */
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gs movw $0x3c00, OFFS_CX(%bp)
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gs movw %ax, OFFS_BX(%bp) /* set BX and DX to number of 64kb chunks - 256 */
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gs movw %ax, OFFS_DX(%bp)
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gs movw OFFS_FLAGS(%bp), %ax
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andw $0xfffe, %ax /* clear carry -- function succeeded */
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gs movw %ax, OFFS_FLAGS(%bp)
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xorw %ax, %ax
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ret
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Lfunc_88h:
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movw ram_in_64kb_chunks, %ax
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subw $16, %ax
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shlw $6, %ax
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gs movw %ax, OFFS_AX(%bp) /* return number of kilobytes in ax */
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gs movw OFFS_FLAGS(%bp), %ax
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andw $0xfffe, %ax /* clear carry -- function succeeded */
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gs movw %ax, OFFS_FLAGS(%bp)
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xorw %ax, %ax
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ret
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/*
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************************************************************
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* BIOS interrupt 16h -- keyboard services
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************************************************************
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*/
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bios_16h:
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gs movw OFFS_AX(%bp), %ax
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shrw $8, %ax
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cmpw $0x03, %ax
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je Lfunc_03h
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movw $0xffff, %ax
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ret
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Lfunc_03h:
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xorw %ax, %ax /* do nothing -- function not supported */
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ret
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.globl ram_in_64kb_chunks
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ram_in_64kb_chunks:
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.word 0
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.globl bios_equipment
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bios_equipment:
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.word 0
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Reference in New Issue
Block a user