1 FILE_LICENCE ( GPL2_OR_LATER ) 2 3 .text 4 .arch i386 5 .section ".prefix", "awx", @progbits 6 .code16 7 .org 0 8 9 movw $load_image, %bp 10 jmp find_active_partition 11 12 #include "bootpart.S" 13 14 load_image: 15 /* Get disk geometry */ 16 pushal 17 pushw %es 18 movb $0x08, %ah 19 int $0x13 20 jc load_failed 21 movb %cl, max_sector 22 movb %dh, max_head 23 popw %es 24 popal 25 26 1: /* Read to end of current track */ 27 movb %cl, %al 28 negb %al 29 addb max_sector, %al 30 incb %al 31 andb $0x3f, %al 32 movzbl %al, %eax 33 call *read_sectors 34 jc load_failed 35 36 /* Update %es */ 37 movw %es, %bx 38 shll $5, %eax 39 addw %ax, %bx 40 movw %bx, %es 41 shrl $5, %eax 42 43 /* Update LBA address */ 44 addl %eax, %edi 45 adcl $0, %esi 46 47 /* Update CHS address */ 48 andb $0xc0, %cl 49 orb $0x01, %cl 50 incb %dh 51 cmpb max_head, %dh 52 jbe 2f 53 xorb %dh, %dh 54 incb %ch 55 jnc 2f 56 addb $0xc0, %cl 57 2: 58 /* Loop until whole image is read */ 59 subl %eax, load_length 60 ja 1b 61 ljmp $BOOT_SEG, $start_image 62 63 max_sector: 64 .byte 0 65 max_head: 66 .byte 0 67 load_length: 68 .long 0 69 70 .section ".zinfo.fixup", "a", @progbits /* Compressor fixups */ 71 .ascii "ADDL" 72 .long load_length 73 .long 512 74 .long 0 75 .previous 76 77 78 load_failed: 79 movw $10f, %si 80 jmp boot_error 81 10: .asciz "Could not load gPXE\r\n" 82 83 .org 510 84 .byte 0x55, 0xaa 85 86 start_image: 87 /* Install gPXE */ 88 call install 89 90 /* Set up real-mode stack */ 91 movw %bx, %ss 92 movw $_estack16, %sp 93 94 /* Jump to .text16 segment */ 95 pushw %ax 96 pushw $1f 97 lret 98 .section ".text16", "awx", @progbits 99 1: 100 pushl $main 101 pushw %cs 102 call prot_call 103 popl %ecx /* discard */ 104 105 /* Uninstall gPXE */ 106 call uninstall 107 108 /* Boot next device */ 109 int $0x18 110
