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| author | H. Peter Anvin <hpa@zytor.com> | 2009-05-25 17:48:58 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2009-05-25 17:48:58 -0700 |
| commit | bb519a95c0da9871fd99b068d00e96fd78cc8cc1 (patch) | |
| tree | ea26286be0797667cf46dde652330e628629553e /mbr | |
| parent | 942aadea9468884dfbc2a7c8428f52bbb5ecf360 (diff) | |
| download | syslinux-bb519a95c0da9871fd99b068d00e96fd78cc8cc1.tar.gz | |
isohybrid: revert to a stack format compatible with previous versionsyslinux-3.81-pre14
Revert the isohybrid handover protocol so that it has a stack format
compatible with the previous versions; that way we can also revert the
magic number to a compatible one.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'mbr')
| -rw-r--r-- | mbr/isohdpfx.S | 35 |
1 files changed, 18 insertions, 17 deletions
diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 53e1ed6b..31a792e8 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -39,15 +39,15 @@ .code16 .text -HYBRID_MAGIC = 0x0defe3f7 +HYBRID_MAGIC = 0x7078c0fb isolinux_hybrid_signature = 0x7c00+64 isolinux_start_hybrid = 0x7c00+64+4 .globl bootsec /* Important: the top 6 words on the stack are passed to isolinux.bin */ stack = 0x7c00 -driveno = (stack-6) -partoffset = (stack-14) +partoffset = (stack-8) +driveno = (stack-14) ebios_flag = (stack-16) sectors = (stack-18) heads = (stack-20) @@ -70,17 +70,19 @@ _start: xorw %bx, %bx movw %bx, %ds movw %bx, %ss - movw $stack, %sp - pushw %es /* -4: es:di -> $PnP header */ + movw $partoffset, %sp + pushw %es /* -12: es:di -> $PnP header */ pushw %di movw %bx, %es sti cld ADJUST_DRIVE - pushw %dx /* -6: dl -> drive number */ + pushw %dx /* -14: dl -> drive number */ /* Check to see if we have a partition table entry */ + xorl %ebx, %ebx + xorl %ecx, %ecx #ifdef PARTITION_SUPPORT andw %si, %si /* %si == 0 -> no partition data */ jz 1f @@ -90,22 +92,21 @@ _start: jne 2f cmpb $0xee, 4(%si) /* EFI partition type? */ jne 2f + /* We have GPT partition information */ - pushl (36+16)(%si) /* -10: partoffset_hi */ - pushl (32+16)(%si) /* -14: partoffset_lo */ - jmp 3f -2: + movl (36+16)(%si), %ecx + movl (32+16)(%si), %ebx + jmp 1f + /* We have non-GPT partition information */ - pushl $0 /* -10: partoffset_hi */ - pushl 8(%si) /* -14: partoffset_lo */ - jmp 3f +2: + movl 8(%si), %ecx #endif 1: /* We have no partition information */ - pushl $0 /* -10: partoffset_hi */ - pushl $0 /* -14: partoffset_lo */ -3: - + movl %ecx, (partoffset) /* -4: partoffset_hi */ + movl %ebx, (partoffset+4) /* -0: partoffset_lo */ + /* Copy down to 0:0x600 */ movw $0x7c00, %si movw $_start, %di |