git.joshuawise.com / netwatch.git / blame
| Commit | Line | Data |
|---|---|---|
| 9e2a82e4 JP |
1 | org 0xA8000 |
| 2 | [bits 16] | |
| 3 | entry: | |
| 4 | mov ax, 0xA800 ; Take us out of flat unreal mode, | |
| 5 | mov ds, ax ; and put us in true real mode. | |
| 6 | mov es, ax | |
| 7 | mov fs, ax | |
| 8 | mov gs, ax | |
| 9 | mov ss, ax | |
| 10 | jmp 0xA800:(entry2-0xA8000) ; Long jump to a correct cs. | |
| 11 | entry2: | |
| 12 | lgdt [(gdtr-0xA8000)] ; Set up a new GDT. | |
| 13 | mov eax, 0x1 | |
| 14 | mov cr0, eax ; ... and enter pmode! | |
| 15 | jmp long 0x10:continue ; Now longjmp into the new code. | |
| 16 | [bits 32] | |
| 17 | continue: | |
| 18 | mov ax, 0x08 ; Set up segment selectors. | |
| 19 | mov ds, ax | |
| 20 | mov es, ax | |
| 21 | mov fs, ax | |
| 22 | mov gs, ax | |
| 23 | mov ss, ax | |
| 24 | mov esp, [dataptr] ; Load stack pointer. | |
| b767eafd JW |
25 | |
| 26 | ; Before we do anything, turn off alignment checking. | |
| 27 | pushf | |
| 28 | pop eax | |
| 29 | and eax, ~(1 << 18) | |
| 30 | push eax | |
| 31 | popf | |
| 9e2a82e4 JP |
32 | |
| 33 | mov eax, [dataptr+4] ; Load target jump address | |
| 34 | call eax ; then jump into C. | |
| 35 | ||
| 36 | rsm ; and leave SMM | |
| 37 | ||
| 38 | align 0x4 | |
| 39 | gdtr: | |
| 40 | db 0x17, 0x00 | |
| 41 | dd gdt | |
| 42 | align 0x4 | |
| 43 | gdt: | |
| 44 | db 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 ; initial null entry | |
| 45 | db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x93, 0xCF, 0x00 ; data segment | |
| 46 | db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9B, 0xCF, 0x00 ; code segment | |
| 47 | ||
| 48 | ||
| 49 | dataptr: | |
| 50 | ; 4 bytes of stack top | |
| 51 | ; 4 bytes of C entry point | |
| 52 | ; These show up |