source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/Initialize.asm@ 253

Last change on this file since 253 was 243, checked in by aitotat@…, 12 years ago

Changes to XTIDE Universal BIOS:

  • Brought back optional "A then C" boot loader.
  • Now there is only one INT 19h handler that remains unchanged.
File size: 2.9 KB
RevLine 
[90]1; Project name : XTIDE Universal BIOS
[3]2; Description : Functions for initializing the BIOS.
3
4; Section containing code
5SECTION .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;--------------------------------------------------------------------
[229]19Initialize_FromMainBiosRomSearch: ; unused entrypoint ok
[3]20 pushf
21 push es
22 push ds
23 ePUSHA
24
[90]25 LOAD_BDA_SEGMENT_TO es, ax
[229]26 sti ; Enable interrupts
27 test BYTE [es:BDA.bKBFlgs1], (1<<2) ; Clears ZF if CTRL is held down
[90]28 jnz SHORT .SkipRomInitialization
[3]29
[229]30 ; Install INT 19h handler (boot loader) where drives are detected
31 mov bx, BIOS_BOOT_LOADER_INTERRUPT_19h
[243]32 mov si, Int19h_BootLoaderHandler
[229]33 call Interrupts_InstallHandlerToVectorInBXFromCSSI
34
[90]35.SkipRomInitialization:
[3]36 ePOPA
37 pop ds
38 pop es
39 popf
40 retf
41
42
43;--------------------------------------------------------------------
44; Initializes the BIOS variables and detects IDE drives.
45;
46; Initialize_AndDetectDrives
47; Parameters:
[90]48; ES: BDA Segment
[3]49; Returns:
[97]50; DS: RAMVARS segment
[3]51; Corrupts registers:
[97]52; All
[3]53;--------------------------------------------------------------------
54Initialize_AndDetectDrives:
[130]55 call BootMenuPrint_InitializeDisplayContext
[3]56 call DetectPrint_RomFoundAtSegment
57 call RamVars_Initialize
[33]58 call Interrupts_InitializeInterruptVectors
[3]59 call DetectDrives_FromAllIDEControllers
[98]60 ; Fall to .StoreDptPointersToIntVectors
[97]61
62;--------------------------------------------------------------------
[98]63; .StoreDptPointersToIntVectors
[97]64; Parameters:
65; DS: RAMVARS segment
66; ES: BDA and interrupt vector segment (zero)
67; Returns:
68; Nothing
69; Corrupts registers:
70; DX, DI
71;--------------------------------------------------------------------
[98]72.StoreDptPointersToIntVectors:
[97]73 mov dl, 80h
[152]74 call RamVars_IsDriveHandledByThisBIOS
75 jnc SHORT .FindForDrive81h ; Store nothing if not our drive
[97]76 call FindDPT_ForDriveNumber ; DPT to DS:DI
[152]77 mov [es:HD0_DPT_POINTER_41h*4], di
78 mov [es:HD0_DPT_POINTER_41h*4+2], ds
[97]79.FindForDrive81h:
80 inc dx
[152]81 call RamVars_IsDriveHandledByThisBIOS
82 jnc SHORT .ResetDetectedDrives
[97]83 call FindDPT_ForDriveNumber
[152]84 mov [es:HD1_DPT_POINTER_46h*4], di
85 mov [es:HD1_DPT_POINTER_46h*4+2], ds
[33]86 ; Fall to .ResetDetectedDrives
[3]87
88;--------------------------------------------------------------------
[97]89; .ResetDetectedDrives
[3]90; Parameters:
91; DS: RAMVARS segment
[243]92; ES: BDA and interrupt vector segment (zero)
[3]93; Returns:
94; Nothing
95; Corrupts registers:
[243]96; All, except DS and ES
[3]97;--------------------------------------------------------------------
[33]98.ResetDetectedDrives:
[150]99 call Idepack_FakeToSSBP
100 call AH0h_ResetHardDisksHandledByOurBIOS
[158]101 add sp, BYTE EXTRA_BYTES_FOR_INTPACK
[150]102 ret
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