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| author | H. Peter Anvin <hpa@zytor.com> | 2007-07-11 15:04:31 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2007-07-11 15:04:31 -0700 |
| commit | 6639ea5c992e99aa7bd1182d2d9e12997be8697e (patch) | |
| tree | 92fdb1fb46d074f379224d69b4168452a0015219 /mbr/mbr.S | |
| parent | 056069afebceef2b84746b2b9db7063bfa67da9f (diff) | |
| download | syslinux-6639ea5c992e99aa7bd1182d2d9e12997be8697e.tar.gz | |
Shave a byte off the MBR code.
Diffstat (limited to 'mbr/mbr.S')
| -rw-r--r-- | mbr/mbr.S | 8 |
1 files changed, 4 insertions, 4 deletions
@@ -32,7 +32,7 @@ stack = 0x7c00 driveno = (stack-6) sectors = (stack-8) -secpercyl = (stack-10) +secpercyl = (stack-12) BIOS_page = 0x462 @@ -92,6 +92,7 @@ next: andw $0x3f, %cx /* Sector count */ pushw %cx /* Save sectors on the stack */ xorw %ax, %ax + pushw %ax /* High word of sectors/cylinder */ movb %dh, %al /* dh = number of heads */ incw %ax /* From 0-based to count */ mulw %cx /* Heads*sectors -> sectors per cylinder */ @@ -111,9 +112,8 @@ next: */ read_sector: read_sector_cbios: - movl %eax, %edx - shrl $16, %edx - divw (secpercyl) + xorl %edx, %edx + divl (secpercyl) rorb %ah rorb %ah movb %ah, %cl |