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Sanity check the drive number in %dl and use it instead of blindly

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assuming disk 0.
This commit is contained in:
fvdl 1999-05-02 13:48:30 +00:00
parent 337300d376
commit 6a2c64449b
1 changed files with 24 additions and 3 deletions
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27
sbin/fdisk/mbr/mbr.S
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@ -1,4 +1,4 @@
/* $NetBSD: mbr.S,v 1.5 1999/04/30 15:29:44 christos Exp $ */
/* $NetBSD: mbr.S,v 1.6 1999/05/02 13:48:30 fvdl Exp $ */
/*
* Copyright (C) 1998 Wolfgang Solfrank.
@ -75,6 +75,14 @@
#define movb_ireg0_reg(ireg,reg) .byte 0x8a ; .byte (reg << 3) | ireg
#define movb_reg_mem(reg,mem) \
.byte 0x88 ; .byte 0x6 | (reg << 3) ; .word mem
#define movb_mem_reg(mem,reg) \
.byte 0x8a ; .byte 0x6 | (reg << 3) ; .word mem
#define MINDRV 0x80
#define MAXDRV 0x87
.text
/*
* Move ourselves out of the way first
@ -101,6 +109,14 @@ ENTRY(start)
.word 0
#endif
1:
cmpb $MINDRV,%dl
jl 2f
cmpb $MAXDRV,%dl
jle 3f
2:
movb $0x80,%dl
3:
movb_reg_mem(DL,drvno)
/*
* Now look for the active partition
*/
@ -144,7 +160,7 @@ invpart:
* try to avoid them unless really necessary.
*/
boot:
movb_ireg0_reg(SI_INDEX,DL)
movb_mem_reg(drvno, DL);
data32
xorl %ecx,%ecx
data32
@ -169,12 +185,14 @@ boot:
data32
mull %ecx /* %eax = c * h * s */
movb_ireg0_reg(SI_INDEX,DL)
movb_mem_reg(drvno, DL)
data32
addr32
movl 8(%esi), %ebx
data32
cmpl %eax, %ebx
data32
jl noext /* total # chs sectors > part. start */
tryext:
@ -276,6 +294,7 @@ ok:
movl $0xaa55, %ebx
cmpl %eax, %ebx
jnz out
movb_mem_reg(drvno, DL)
#ifdef ASSEMBLE_16BIT
jmp 0:BOOTADDR
#else
@ -284,6 +303,8 @@ ok:
.word 0
#endif
drvno:
.byte 0x80
msinvp:
.asciz "Invalid partition table"
noos: