fix many bugs in the BIOS drive remapping feature.
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okuji
parent
9d7344365c
commit
482c5a1631
4 changed files with 86 additions and 46 deletions
23
ChangeLog
23
ChangeLog
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@ -1,3 +1,26 @@
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1999-10-26 OKUJI Yoshinori <okuji@kuicr.kyoto-u.ac.jp>
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Now the BIOS drive remapping is functional.
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* stage2/asm.S [DEFINE_TRACK_INT13] (track_int13): Use %edi
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instead of direct addresses.
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Prefix DATA32 to the calls for real_to_prot and prot_to_real.
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Fix the address of DRIVE: 4(%ebp) -> 8(%ebp).
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(set_int15_handler): Use %edi instead of direct addresses.
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(unset_int15_handler): Likewise.
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(set_int13_handler): Copy DRIVE_MAP_SIZE * 2 bytes instead of
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DRIVE_MAP_SIZE bytes of MAP.
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Fix the address of MAP: 4(%ebp) -> 8(%ebp).
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Use %edi instead of direct addresses.
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(int13_handler): Do not set %ds to %cs. Use the segment override
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prefix of %cs instead.
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Push the flags pushed by the callee instead of the current.
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Set the flags in the stack to the flags returned by the original
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int13 call.
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(drive_map): 4bytes-aligned.
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* stage2/disk_io.c (grub_close): Do not set ERRNUM even if
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FSYS_TYPE is NUM_FSYS.
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1999-10-25 OKUJI Yoshinori <okuji@kuicr.kyoto-u.ac.jp>
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* stage1/stage1.S: Long jump to real_start, because some bogus
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102
stage2/asm.S
102
stage2/asm.S
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@ -199,13 +199,15 @@ ENTRY(track_int13)
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pushl %edx
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pushl %ebx
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pushl %edi
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/* computer the linear address of int13 handler */
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movl $0x4c, %edi
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xorl %ebx, %ebx
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xorl %eax, %eax
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movw 0x13 * 4 + 2, %ax
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movw 2(%edi), %ax
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shll $4, %eax
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movw 0x13 * 4, %bx
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movw (%edi), %bx
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addl %eax, %ebx
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/* save the first intruction */
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@ -216,19 +218,21 @@ ENTRY(track_int13)
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movb $0xCC, (%ebx)
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/* replace the int1 handler */
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pushl 0x1 * 4
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movl 0x4, %edi
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pushl (%edi)
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movl $ABS(int1_handler), %eax
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movl %eax, 0x1 * 4
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movl %eax, (%edi)
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/* replace the int3 handler */
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pushl 0x3 * 4
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movl 0xc, %edi
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pushl (%edi)
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movl $ABS(int3_handler), %eax
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movl %eax, 0x3 * 4
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movl %eax, (%edi)
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/* read the MBR to call int13 successfully */
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movb 4(%ebp), %dl
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movb 8(%ebp), %dl
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call prot_to_real
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DATA32 call EXT_C(prot_to_real)
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.code16
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movw $SCRATCHSEG, %ax
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@ -240,15 +244,18 @@ ENTRY(track_int13)
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movw $0x201, %ax
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int $0x13
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call real_to_prot
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DATA32 call EXT_C(real_to_prot)
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.code32
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/* restore the int3 handler */
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popl 0x3 * 4
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movl 0xc, %edi
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popl (%edi)
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/* restore the int1 handler */
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popl 0x1 * 4
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movl 0x4, %edi
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popl (%edi)
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popl %edi
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popl %ebx
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popl %edx
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popl %ebp
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@ -416,19 +423,23 @@ ENTRY(io_map)
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* Set up int15_handler.
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*/
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ENTRY(set_int15_handler)
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pushl %edi
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/* save the original int15 handler */
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movw 0x15 * 4, %ax
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movl $0x54, %edi
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movw (%edi), %ax
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movw %ax, ABS(int15_offset)
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movw 0x15 * 4 + 2, %ax
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movw 2(%edi), %ax
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movw %ax, ABS(int15_segment)
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/* save the new int15 handler */
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movl $ABS(int15_handler), %eax
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rorl $4, %eax
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movw %ax, 0x15 * 4 + 2
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movw %ax, 2(%edi)
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shrl $28, %eax
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movw %ax, 0x15 * 4
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movw %ax, (%edi)
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popl %edi
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ret
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@ -438,22 +449,26 @@ ENTRY(set_int15_handler)
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* Restore the original int15 handler
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*/
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ENTRY(unset_int15_handler)
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pushl %edi
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/* check if int15_handler is set */
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movl $0x54, %edi
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movl $ABS(int15_handler), %eax
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rorl $4, %eax
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cmpw %ax, 0x15 * 4 + 2
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cmpw %ax, 2(%edi)
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jne 1f
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shrl $28, %eax
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cmpw %ax, 0x15 * 4
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cmpw %ax, (%edi)
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jne 1f
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/* restore the original */
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movw ABS(int15_offset), %ax
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movw %ax, 0x15 * 4
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movw %ax, (%edi)
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movw ABS(int15_segment), %ax
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movw %ax, 0x15 * 4 + 2
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movw %ax, 2(%edi)
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1:
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popl %edi
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ret
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@ -525,17 +540,18 @@ ENTRY(set_int13_handler)
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pushl %esi
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/* copy MAP to the drive map */
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movl $DRIVE_MAP_SIZE, %ecx
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movl $(DRIVE_MAP_SIZE * 2), %ecx
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movl $ABS(drive_map), %edi
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movl 4(%ebp), %esi
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movl 8(%ebp), %esi
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cld
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rep
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movsb
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/* save the original int13 handler */
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movw 0x13 * 4, %ax
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movl $0x4c, %edi
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movw (%edi), %ax
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movw %ax, ABS(int13_offset)
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movw 0x13 * 4 + 2, %ax
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movw 2(%edi), %ax
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movw %ax, ABS(int13_segment)
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/* get the lower memory size */
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@ -543,14 +559,16 @@ ENTRY(set_int13_handler)
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movl 4(%edi), %eax
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/* decrease the lower memory size and set it to the BIOS memory */
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decl %eax
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movw %ax, 0x413
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movl $0x413, %edi
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movw %ax, (%edi)
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/* compute the segment */
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shll $6, %eax
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/* save the new int13 handler */
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movw %ax, 0x13 * 4 + 2
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xorw %ax, %ax
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movw %ax, 0x13 * 4
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movl $0x4c, %edi
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movw %ax, 2(%edi)
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xorw %cx, %cx
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movw %cx, (%edi)
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/* copy int13_handler to the reserved area */
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shll $4, %eax
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@ -565,7 +583,7 @@ ENTRY(set_int13_handler)
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popl %ecx
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popl %ebp
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ret
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/*
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* Map a drive to another drive.
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@ -578,17 +596,14 @@ int13_handler:
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pushw %bp
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movw %sp, %bp
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pushw %ds
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pushw %si
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/* set %ds to %cs */
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movw %cs, %ax
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movw %ax, %ds
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/* set %si to the drive map */
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movw $(drive_map - int13_handler), %si
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/* find the drive number from the drive map */
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cld
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1:
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lodsw
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lodsw %cs:(%si), %ax
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/* check if this is the end */
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testw %ax, %ax
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jz 2f
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@ -598,42 +613,47 @@ int13_handler:
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/* if so, perform the mapping */
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movb %ah, %dl
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2:
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/* restore %si and %ds */
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/* restore %si */
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popw %si
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popw %ds
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/* save %ax in the stack */
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pushw %ax
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/* simulate the interrupt call */
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pushw 8(%bp)
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/* set %ax and %bp to the original values */
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movw 2(%bp), %ax
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movw (%bp), %bp
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/* simulate the interrupt call */
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pushf
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/* ljmp */
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.byte 0x9a
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int13_offset: .word 0
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int13_segment: .word 0
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/* save flags */
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pushf
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/* restore %bp */
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movw %sp, %bp
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/* save %ax */
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pushw %ax
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/* set the flags in the stack to the value returned by int13 */
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movw (%bp), %ax
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movw %ax, 0xc(%bp)
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/* check if should map the drive number */
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movw 4(%bp), %ax
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movw 6(%bp), %ax
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cmpw $0x8, %ax
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jne 3f
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cmpw $0x15, %ax
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jne 3f
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/* check if the mapping was performed */
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movw (%bp), %ax
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movw 2(%bp), %ax
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testw %ax, %ax
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jz 3f
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/* perform the mapping */
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movb %al, %dl
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3:
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popw %ax
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movw 2(%bp), %bp
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addw $6, %sp
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movw 4(%bp), %bp
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addw $8, %sp
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iret
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.align 4
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drive_map: .space (DRIVE_MAP_SIZE + 1) * 2
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int13_handler_end:
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@ -131,7 +131,7 @@ boot_func (char *arg, int flags)
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/* Set the handler. This is somewhat dangerous. */
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set_int13_handler (bios_drive_map);
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}
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gateA20 (0);
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boot_drive = saved_drive;
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chain_stage1 (0, BOOTSEC_LOCATION, BOOTSEC_LOCATION - 16);
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@ -1518,10 +1518,7 @@ void
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grub_close (void)
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{
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if (fsys_type == NUM_FSYS)
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{
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errnum = ERR_FSYS_MOUNT;
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return;
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}
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return;
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if (fsys_table[fsys_type].close_func == 0)
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return;
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