diff options
Diffstat (limited to 'roms/ipxe/src/arch/x86/prefix/hdprefix.S')
| -rw-r--r-- | roms/ipxe/src/arch/x86/prefix/hdprefix.S | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/roms/ipxe/src/arch/x86/prefix/hdprefix.S b/roms/ipxe/src/arch/x86/prefix/hdprefix.S new file mode 100644 index 000000000..28c8a532d --- /dev/null +++ b/roms/ipxe/src/arch/x86/prefix/hdprefix.S @@ -0,0 +1,115 @@ +FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ) + +#include <librm.h> + + .text + .arch i386 + .section ".prefix", "awx", @progbits + .code16 + .org 0 + .globl _hd_start +_hd_start: + + movw $load_image, %bp + jmp find_active_partition + +#include "bootpart.S" + +load_image: + /* Get disk geometry */ + pushal + pushw %es + movb $0x08, %ah + int $0x13 + jc load_failed + movb %cl, max_sector + movb %dh, max_head + popw %es + popal + +1: /* Read to end of current track (or end of image) */ + movb %cl, %al + negb %al + addb max_sector, %al + incb %al + andb $0x3f, %al + movzbl %al, %eax + movl load_length, %ebx + cmpl %eax, %ebx + ja 2f + movl %ebx, %eax +2: call *read_sectors + jc load_failed + + /* Update %es */ + movw %es, %bx + shll $5, %eax + addw %ax, %bx + movw %bx, %es + shrl $5, %eax + + /* Update LBA address */ + addl %eax, %edi + adcl $0, %esi + + /* Update CHS address */ + andb $0xc0, %cl + orb $0x01, %cl + incb %dh + cmpb max_head, %dh + jbe 3f + xorb %dh, %dh + incb %ch + jnc 3f + addb $0xc0, %cl +3: + /* Loop until whole image is read */ + subl %eax, load_length + ja 1b + ljmp $BOOT_SEG, $start_image + +max_sector: + .byte 0 +max_head: + .byte 0 +load_length: + .long 0 + + .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */ + .ascii "ADDL" + .long load_length + .long 512 + .long 0 + .previous + + +load_failed: + movw $10f, %si + jmp boot_error +10: .asciz "Could not load iPXE\r\n" + + .org 510 + .byte 0x55, 0xaa + +start_image: + /* Install iPXE */ + call install + + /* Set up real-mode stack */ + movw %bx, %ss + movw $_estack16, %sp + + /* Jump to .text16 segment */ + pushw %ax + pushw $1f + lret + .section ".text16", "awx", @progbits +1: + /* Run iPXE */ + virtcall main + + /* Uninstall iPXE */ + call uninstall + + /* Boot next device */ + int $0x18 |