1 | ; Project name : XTIDE Universal BIOS |
---|
2 | ; Description : Functions to access BOOTVARS struct. |
---|
3 | |
---|
4 | ; Section containing code |
---|
5 | SECTION .text |
---|
6 | |
---|
7 | ;-------------------------------------------------------------------- |
---|
8 | ; Stores POST stack pointer to BOOTVARS. |
---|
9 | ; |
---|
10 | ; BootVars_StorePostStackPointer |
---|
11 | ; Parameters: |
---|
12 | ; DS: BDA and Interrupt Vector segment (zero) |
---|
13 | ; Returns: |
---|
14 | ; Nothing |
---|
15 | ; Corrupts registers: |
---|
16 | ; AX |
---|
17 | ;-------------------------------------------------------------------- |
---|
18 | ALIGN JUMP_ALIGN |
---|
19 | BootVars_StorePostStackPointer: |
---|
20 | pop ax ; Pop return address |
---|
21 | mov [BOOTVARS.dwPostStack], sp |
---|
22 | mov [BOOTVARS.dwPostStack+2], ss |
---|
23 | jmp ax |
---|
24 | |
---|
25 | |
---|
26 | ;-------------------------------------------------------------------- |
---|
27 | ; Initializes stack for boot menu usage. |
---|
28 | ; POST stack is not large enough when DPTs are stored to 30:0h. |
---|
29 | ; |
---|
30 | ; BootVars_SwitchToBootMenuStack |
---|
31 | ; Parameters: |
---|
32 | ; Nothing |
---|
33 | ; Returns: |
---|
34 | ; SS:SP: Pointer to top of Boot Menu stack |
---|
35 | ; Corrupts registers: |
---|
36 | ; AX |
---|
37 | ;-------------------------------------------------------------------- |
---|
38 | ALIGN JUMP_ALIGN |
---|
39 | BootVars_SwitchToBootMenuStack: |
---|
40 | pop ax ; Pop return address |
---|
41 | cli ; Disable interrupts |
---|
42 | LOAD_BDA_SEGMENT_TO ss, sp |
---|
43 | mov sp, BOOTVARS.rgbMnuStack ; Load offset to stack |
---|
44 | sti ; Enable interrupts |
---|
45 | jmp ax |
---|
46 | |
---|
47 | |
---|
48 | ;-------------------------------------------------------------------- |
---|
49 | ; Restores SS and SP to initial boot loader values. |
---|
50 | ; |
---|
51 | ; BootVars_SwitchBackToPostStack |
---|
52 | ; Parameters: |
---|
53 | ; Nothing |
---|
54 | ; Returns: |
---|
55 | ; SS:SP: Ptr to POST stack |
---|
56 | ; Corrupts registers: |
---|
57 | ; AX |
---|
58 | ;-------------------------------------------------------------------- |
---|
59 | ALIGN JUMP_ALIGN |
---|
60 | BootVars_SwitchBackToPostStack: |
---|
61 | pop ax ; Pop return address |
---|
62 | cli ; Disable interrupts |
---|
63 | LOAD_BDA_SEGMENT_TO ss, sp |
---|
64 | %ifndef USE_386 |
---|
65 | mov sp, [ss:BOOTVARS.dwPostStack] |
---|
66 | mov ss, [ss:BOOTVARS.dwPostStack+2] |
---|
67 | %else |
---|
68 | lss sp, [ss:BOOTVARS.dwPostStack] |
---|
69 | %endif |
---|
70 | sti ; Enable interrupts |
---|
71 | jmp ax |
---|