| 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 | ; eLSS sp, ss:BOOTVARS.dwPostStack ; Expanded macro to remove
|
|---|
| 65 | ; unneeded CLI instruction
|
|---|
| 66 | %ifndef USE_386
|
|---|
| 67 | mov sp, [ss:BOOTVARS.dwPostStack]
|
|---|
| 68 | mov ss, [ss:BOOTVARS.dwPostStack+2]
|
|---|
| 69 | %else
|
|---|
| 70 | lss sp, [ss:BOOTVARS.dwPostStack]
|
|---|
| 71 | %endif
|
|---|
| 72 | sti ; Enable interrupts
|
|---|
| 73 | jmp ax
|
|---|
