9fefd40478
breaks zero-extension of the 16-bit memory size return from the BIOS. on at least one system, the trash left in the upper half of %eax causes the kernel to crash during VM system initialization when it thinks it has on the order of 2**31 bytes of memory to play with. We now *say* mov %eax,%ebx, but *mean* mov %ax,%bx..
100 lines
2.5 KiB
ArmAsm
100 lines
2.5 KiB
ArmAsm
/* $NetBSD: biosmem.S,v 1.2 1997/03/19 18:12:10 sommerfe Exp $ */
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/*
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* Copyright (c) 1996
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* Perry E. Metzger. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgements:
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* This product includes software developed for the NetBSD Project
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* by Perry E. Metzger.
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* 4. The names of the authors may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include <machine/asm.h>
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#define data32 .byte 0x66
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.text
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/* get mem above 1M, in kByte */
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ENTRY(getbasemem)
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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push %esi
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push %edi
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call _C_LABEL(prot_to_real)
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int $0x12
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# zero-extend 16-bit result to 32 bits.
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data32
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movl $0, %ebx
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mov %eax,%ebx # !!! at run time, it's mov %ax,%bx
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data32
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call _C_LABEL(real_to_prot)
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movl %ebx, %eax
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pop %edi
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pop %esi
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popl %ebx
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popl %ebp
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ret
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/* get mem above 1M, in kByte */
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ENTRY(getextmem)
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pushl %ebp
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movl %esp,%ebp
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pushl %ebx
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push %esi
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push %edi
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call _C_LABEL(prot_to_real)
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movb $0x88,%ah
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int $0x15
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# zero-extend 16-bit result to 32 bits.
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data32
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movl $0, %ebx
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mov %eax,%ebx # !!! at run time, it's mov %ax,%bx
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data32
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call _C_LABEL(real_to_prot)
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movl %ebx, %eax
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pop %edi
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pop %esi
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popl %ebx
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popl %ebp
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ret
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