[src/trunk]: src/sbin/fdisk/mbr Sanity check the drive number in %dl and use ...

[fvdl <fvdl%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/89afa0cebbb2
branches:  trunk
changeset: 472561:89afa0cebbb2
user:      fvdl <fvdl%NetBSD.org@localhost>
date:      Sun May 02 13:48:30 1999 +0000

description:
Sanity check the drive number in %dl and use it instead of blindly
assuming disk 0.

diffstat:

 sbin/fdisk/mbr/mbr.S |  27 ++++++++++++++++++++++++---
 1 files changed, 24 insertions(+), 3 deletions(-)

diffs (81 lines):

diff -r 65552b1a0165 -r 89afa0cebbb2 sbin/fdisk/mbr/mbr.S
--- a/sbin/fdisk/mbr/mbr.S      Sun May 02 13:07:15 1999 +0000
+++ b/sbin/fdisk/mbr/mbr.S      Sun May 02 13:48:30 1999 +0000
@@ -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 @@
        .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 @@
  * 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 @@
        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 @@
        movl    $0xaa55, %ebx
        cmpl    %eax, %ebx
        jnz     out
+       movb_mem_reg(drvno, DL)
 #ifdef ASSEMBLE_16BIT
        jmp     0:BOOTADDR
 #else
@@ -284,6 +303,8 @@
        .word   0
 #endif
 
+drvno:
+       .byte 0x80
 msinvp:
        .asciz  "Invalid partition table"
 noos: