| 1 | ; Project name : XTIDE Universal BIOS
|
|---|
| 2 | ; Description : Functions for initializing the BIOS.
|
|---|
| 3 |
|
|---|
| 4 | ; Section containing code
|
|---|
| 5 | SECTION .text
|
|---|
| 6 |
|
|---|
| 7 | ;--------------------------------------------------------------------
|
|---|
| 8 | ; Initializes the BIOS.
|
|---|
| 9 | ; This function is called from main BIOS ROM search routine.
|
|---|
| 10 | ;
|
|---|
| 11 | ; Initialize_FromMainBiosRomSearch
|
|---|
| 12 | ; Parameters:
|
|---|
| 13 | ; Nothing
|
|---|
| 14 | ; Returns:
|
|---|
| 15 | ; Nothing
|
|---|
| 16 | ; Corrupts registers:
|
|---|
| 17 | ; Nothing
|
|---|
| 18 | ;--------------------------------------------------------------------
|
|---|
| 19 | Initialize_FromMainBiosRomSearch: ; unused entrypoint ok
|
|---|
| 20 | pushf
|
|---|
| 21 | push es
|
|---|
| 22 | push ds
|
|---|
| 23 | ePUSHA
|
|---|
| 24 |
|
|---|
| 25 | LOAD_BDA_SEGMENT_TO es, ax
|
|---|
| 26 | sti ; Enable interrupts
|
|---|
| 27 | test BYTE [es:BDA.bKBFlgs1], (1<<2) ; Clears ZF if CTRL is held down
|
|---|
| 28 | jnz SHORT .SkipRomInitialization
|
|---|
| 29 |
|
|---|
| 30 | ; Install INT 19h handler (boot loader) where drives are detected
|
|---|
| 31 | mov bx, BIOS_BOOT_LOADER_INTERRUPT_19h
|
|---|
| 32 | mov si, HandlerForLateInitialization
|
|---|
| 33 | call Interrupts_InstallHandlerToVectorInBXFromCSSI
|
|---|
| 34 |
|
|---|
| 35 | .SkipRomInitialization:
|
|---|
| 36 | ePOPA
|
|---|
| 37 | pop ds
|
|---|
| 38 | pop es
|
|---|
| 39 | popf
|
|---|
| 40 | retf
|
|---|
| 41 |
|
|---|
| 42 |
|
|---|
| 43 | ;--------------------------------------------------------------------
|
|---|
| 44 | ; HandlerForLateInitialization
|
|---|
| 45 | ; Parameters:
|
|---|
| 46 | ; Nothing
|
|---|
| 47 | ; Returns:
|
|---|
| 48 | ; Never returns
|
|---|
| 49 | ;--------------------------------------------------------------------
|
|---|
| 50 | HandlerForLateInitialization:
|
|---|
| 51 | LOAD_BDA_SEGMENT_TO es, ax
|
|---|
| 52 | call Initialize_AndDetectDrives ; Installs new boot menu loader
|
|---|
| 53 | int BIOS_BOOT_LOADER_INTERRUPT_19h ; Display boot menu
|
|---|
| 54 |
|
|---|
| 55 |
|
|---|
| 56 | ;--------------------------------------------------------------------
|
|---|
| 57 | ; Initializes the BIOS variables and detects IDE drives.
|
|---|
| 58 | ;
|
|---|
| 59 | ; Initialize_AndDetectDrives
|
|---|
| 60 | ; Parameters:
|
|---|
| 61 | ; ES: BDA Segment
|
|---|
| 62 | ; Returns:
|
|---|
| 63 | ; DS: RAMVARS segment
|
|---|
| 64 | ; Corrupts registers:
|
|---|
| 65 | ; All
|
|---|
| 66 | ;--------------------------------------------------------------------
|
|---|
| 67 | Initialize_AndDetectDrives:
|
|---|
| 68 | call BootMenuPrint_InitializeDisplayContext
|
|---|
| 69 | call DetectPrint_RomFoundAtSegment
|
|---|
| 70 | call RamVars_Initialize
|
|---|
| 71 | call Interrupts_InitializeInterruptVectors
|
|---|
| 72 | call DetectDrives_FromAllIDEControllers
|
|---|
| 73 | ; Fall to .StoreDptPointersToIntVectors
|
|---|
| 74 |
|
|---|
| 75 | ;--------------------------------------------------------------------
|
|---|
| 76 | ; .StoreDptPointersToIntVectors
|
|---|
| 77 | ; Parameters:
|
|---|
| 78 | ; DS: RAMVARS segment
|
|---|
| 79 | ; ES: BDA and interrupt vector segment (zero)
|
|---|
| 80 | ; Returns:
|
|---|
| 81 | ; Nothing
|
|---|
| 82 | ; Corrupts registers:
|
|---|
| 83 | ; DX, DI
|
|---|
| 84 | ;--------------------------------------------------------------------
|
|---|
| 85 | .StoreDptPointersToIntVectors:
|
|---|
| 86 | mov dl, 80h
|
|---|
| 87 | call RamVars_IsDriveHandledByThisBIOS
|
|---|
| 88 | jnc SHORT .FindForDrive81h ; Store nothing if not our drive
|
|---|
| 89 | call FindDPT_ForDriveNumber ; DPT to DS:DI
|
|---|
| 90 | mov [es:HD0_DPT_POINTER_41h*4], di
|
|---|
| 91 | mov [es:HD0_DPT_POINTER_41h*4+2], ds
|
|---|
| 92 | .FindForDrive81h:
|
|---|
| 93 | inc dx
|
|---|
| 94 | call RamVars_IsDriveHandledByThisBIOS
|
|---|
| 95 | jnc SHORT .ResetDetectedDrives
|
|---|
| 96 | call FindDPT_ForDriveNumber
|
|---|
| 97 | mov [es:HD1_DPT_POINTER_46h*4], di
|
|---|
| 98 | mov [es:HD1_DPT_POINTER_46h*4+2], ds
|
|---|
| 99 | ; Fall to .ResetDetectedDrives
|
|---|
| 100 |
|
|---|
| 101 | ;--------------------------------------------------------------------
|
|---|
| 102 | ; .ResetDetectedDrives
|
|---|
| 103 | ; Parameters:
|
|---|
| 104 | ; DS: RAMVARS segment
|
|---|
| 105 | ; Returns:
|
|---|
| 106 | ; Nothing
|
|---|
| 107 | ; Corrupts registers:
|
|---|
| 108 | ; All
|
|---|
| 109 | ;--------------------------------------------------------------------
|
|---|
| 110 | .ResetDetectedDrives:
|
|---|
| 111 | call Idepack_FakeToSSBP
|
|---|
| 112 | call AH0h_ResetHardDisksHandledByOurBIOS
|
|---|
| 113 | add sp, BYTE EXTRA_BYTES_FOR_INTPACK
|
|---|
| 114 | ret
|
|---|
