diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2007-07-11 16:51:46 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2007-07-11 16:51:46 -0700 |
| commit | 289d77c6733182088953a02b9c09776272b04203 (patch) | |
| tree | 9dc01c98f1c63122b74dd827e336e70af69931cb /mbr | |
| parent | a9a2963de68bfb52c51c793c5325608a99f60d91 (diff) | |
| download | syslinux-289d77c6733182088953a02b9c09776272b04203.tar.gz | |
MBR: Don't clobber %eax before entering CBIOS code
Diffstat (limited to 'mbr')
| -rw-r--r-- | mbr/mbr.S | 8 |
1 files changed, 5 insertions, 3 deletions
@@ -80,8 +80,10 @@ next: shrw %cx /* Bit 0 = fixed disk subset */ jnc 1f - /* We have EBIOS; patch in jump to skip over read_sector_cbios */ - movw $0xeb+((read_common-read_sector_cbios-2)<< 8), (read_sector_cbios) + /* We have EBIOS; patch in the following code at + read_sector_cbios: movb $0x42, %ah ; jmp read_common */ + movl $0xeb42b4+((read_common-read_sector_cbios-4) << 24), \ + (read_sector_cbios) 1: popw %dx @@ -120,9 +122,9 @@ read_sector: pushw $1 /* Sector count */ pushw $16 /* Size of packet */ movw %sp, %si - movb $0x42, %ah /* This chunk is skipped if we have ebios */ + /* Do not clobber %eax before this chunk! */ read_sector_cbios: divl (secpercyl) shlb $6, %ah |