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source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/Interrupts.asm@ 246

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Last change on this file since 246 was 243, checked in by aitotat@…, 13 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: 6.7 KB

Rev	Line
[90]	1	; Project name : XTIDE Universal BIOS
[33]	2	; Description : Functions for initializing the BIOS.
	3
	4	; Section containing code
	5	SECTION .text
	6
	7	;--------------------------------------------------------------------
	8	; Interrupts_InitializeInterruptVectors
	9	; Parameters:
	10	; DS: RAMVARS segment
	11	; ES: BDA and Interrupt Vector segment (zero)
	12	; Returns:
	13	; Nothing
	14	; Corrupts registers:
	15	; All except segments
[86]	16	;--------------------------------------------------------------------
[33]	17	Interrupts_InitializeInterruptVectors:
[97]	18	; Fall to .InitializeInt13hAnd40h
[33]	19
	20	;--------------------------------------------------------------------
[97]	21	; .InitializeInt13hAnd40h
[33]	22	; Parameters:
	23	; DS: RAMVARS segment
	24	; ES: BDA and Interrupt Vector segment (zero)
	25	; Returns:
	26	; Nothing
	27	; Corrupts registers:
	28	; AX, BX, CX, DX, SI, DI
[86]	29	;--------------------------------------------------------------------
[97]	30	.InitializeInt13hAnd40h:
[181]	31	mov ax, [es:BIOS_DISK_INTERRUPT_13h*4+2]; Load old INT 13h segment
	32	mov [RAMVARS.fpOldI13h+2], ax ; Store old INT 13h segment
	33	xchg dx, ax
[152]	34	mov ax, [es:BIOS_DISK_INTERRUPT_13h*4] ; Load old INT 13h offset
[33]	35	mov [RAMVARS.fpOldI13h], ax ; Store old INT 13h offset
[181]	36
[152]	37	mov bx, BIOS_DISK_INTERRUPT_13h ; INT 13h interrupt vector offset
[148]	38	mov si, Int13h_DiskFunctionsHandler ; Interrupt handler offset
[33]	39	call Interrupts_InstallHandlerToVectorInBXFromCSSI
	40
	41	; Only store INT 13h handler to 40h if 40h is not already installed.
	42	; At least AMI BIOS for 286 stores 40h handler by itself and calls
	43	; 40h from 13h. That system locks to infinite loop if we copy 13h to 40h.
	44	call FloppyDrive_IsInt40hInstalled
[243]	45	jc SHORT .Int40hAlreadyInstalled
[152]	46	mov [es:BIOS_DISKETTE_INTERRUPT_40h*4], ax ; Store old INT 13h offset
	47	mov [es:BIOS_DISKETTE_INTERRUPT_40h*4+2], dx ; Store old INT 13h segment
[243]	48	.Int40hAlreadyInstalled:
[97]	49	; Fall to .InitializeHardwareIrqHandlers
[33]	50
	51	;--------------------------------------------------------------------
[97]	52	; .InitializeHardwareIrqHandlers
[33]	53	; Parameters:
	54	; ES: BDA and Interrupt Vector segment (zero)
	55	; Returns:
	56	; Nothing
	57	; Corrupts registers:
	58	; BX, CX, DX, SI, DI
[86]	59	;--------------------------------------------------------------------
[97]	60	.InitializeHardwareIrqHandlers:
[33]	61	call RamVars_GetIdeControllerCountToCX
	62	mov di, ROMVARS.ideVars0 ; CS:SI points to first IDEVARS
	63	.IdeControllerLoop:
	64	eMOVZX bx, BYTE [cs:di+IDEVARS.bIRQ]
	65	add di, BYTE IDEVARS_size ; Increment to next controller
	66	call .InstallLowOrHighIrqHandler
	67	loop .IdeControllerLoop
[86]	68	.Return:
	69	ret ; This ret is shared with .InstallLowOrHighIrqHandler
[33]	70
	71	;--------------------------------------------------------------------
	72	; .InstallLowOrHighIrqHandler
	73	; Parameters:
	74	; BX: IRQ number, 0 if IRQ disabled
	75	; ES: BDA and Interrupt Vector segment (zero)
	76	; Returns:
	77	; Nothing
	78	; Corrupts registers:
	79	; BX, SI
[86]	80	;--------------------------------------------------------------------
[33]	81	.InstallLowOrHighIrqHandler:
[86]	82	test bl, bl
	83	jz SHORT .Return ; IRQ not used
[33]	84	cmp bl, 8
[86]	85	jb SHORT .InstallLowIrqHandler
[162]	86	; Fall to .InstallHighIrqHandler
[33]	87
	88	;--------------------------------------------------------------------
	89	; .InstallHighIrqHandler
	90	; Parameters:
	91	; BX: IRQ number (8...15)
	92	; ES: BDA and Interrupt Vector segment (zero)
	93	; Returns:
	94	; Nothing
	95	; Corrupts registers:
	96	; BX, SI
[86]	97	;--------------------------------------------------------------------
[97]	98	.InstallHighIrqHandler:
[152]	99	add bx, BYTE HARDWARE_IRQ_8_INTERRUPT_70h - 8 ; Interrupt vector number
[150]	100	mov si, IdeIrq_InterruptServiceRoutineForIrqs8to15
[33]	101	jmp SHORT Interrupts_InstallHandlerToVectorInBXFromCSSI
	102
	103	;--------------------------------------------------------------------
	104	; .InstallLowIrqHandler
	105	; Parameters:
	106	; BX: IRQ number (0...7)
	107	; ES: BDA and Interrupt Vector segment (zero)
	108	; Returns:
	109	; Nothing
	110	; Corrupts registers:
	111	; BX, SI
[86]	112	;--------------------------------------------------------------------
[33]	113	.InstallLowIrqHandler:
[152]	114	add bx, BYTE HARDWARE_IRQ_0_INTERRUPT_08h ; Interrupt vector number
[150]	115	mov si, IdeIrq_InterruptServiceRoutineForIrqs2to7
[33]	116	; Fall to Interrupts_InstallHandlerToVectorInBXFromCSSI
	117
	118
	119	;--------------------------------------------------------------------
	120	; Interrupts_InstallHandlerToVectorInBXFromCSSI
	121	; Parameters:
	122	; BX: Interrupt vector number (for example 13h)
	123	; ES: BDA and Interrupt Vector segment (zero)
	124	; CS:SI: Ptr to interrupt handler
	125	; Returns:
	126	; Nothing
	127	; Corrupts registers:
	128	; BX
[86]	129	;--------------------------------------------------------------------
[33]	130	Interrupts_InstallHandlerToVectorInBXFromCSSI:
[123]	131	eSHL_IM bx, 2 ; Shift for DWORD offset
[33]	132	mov [es:bx], si ; Store offset
	133	mov [es:bx+2], cs ; Store segment
	134	ret
	135
	136
	137	;--------------------------------------------------------------------
	138	; Interrupts_UnmaskInterruptControllerForDriveInDSDI
	139	; Parameters:
	140	; DS:DI: Ptr to DPT
	141	; Returns:
	142	; Nothing
	143	; Corrupts registers:
	144	; AX, BX, DX
	145	;--------------------------------------------------------------------
	146	Interrupts_UnmaskInterruptControllerForDriveInDSDI:
[150]	147	eMOVZX bx, BYTE [di+DPT.bIdevarsOffset]
[33]	148	mov al, [cs:bx+IDEVARS.bIRQ]
[86]	149	test al, al
	150	jz SHORT .Return ; Interrupts disabled
[33]	151	cmp al, 8
[86]	152	jb SHORT .UnmaskLowIrqController
[162]	153	; Fall to .UnmaskHighIrqController
[33]	154
	155	;--------------------------------------------------------------------
	156	; .UnmaskHighIrqController
	157	; Parameters:
	158	; AL: IRQ number (8...15)
	159	; Returns:
	160	; Nothing
	161	; Corrupts registers:
	162	; AX, DX
	163	;--------------------------------------------------------------------
[97]	164	.UnmaskHighIrqController:
[33]	165	sub al, 8 ; Slave interrupt number
[152]	166	mov dx, SLAVE_8259_IMR
[33]	167	call .ClearBitFrom8259MaskRegister
	168	mov al, 2 ; Master IRQ 2 to allow slave IRQs
	169	; Fall to .UnmaskLowIrqController
	170
	171	;--------------------------------------------------------------------
	172	; .UnmaskLowIrqController
	173	; Parameters:
	174	; AL: IRQ number (0...7)
	175	; Returns:
	176	; Nothing
	177	; Corrupts registers:
	178	; AX, DX
	179	;--------------------------------------------------------------------
	180	.UnmaskLowIrqController:
[152]	181	mov dx, MASTER_8259_IMR
[33]	182	; Fall to .ClearBitFrom8259MaskRegister
	183
	184	;--------------------------------------------------------------------
	185	; .ClearBitFrom8259MaskRegister
	186	; Parameters:
	187	; AL: 8259 interrupt index (0...7)
	188	; DX: Port address to Interrupt Mask Register
	189	; Returns:
	190	; Nothing
	191	; Corrupts registers:
	192	; AX
	193	;--------------------------------------------------------------------
	194	.ClearBitFrom8259MaskRegister:
	195	push cx
	196	xchg ax, cx ; IRQ index to CL
	197	mov ch, 1 ; Load 1 to be shifted
	198	shl ch, cl ; Shift bit to correct position
	199	not ch ; Invert to create bit mask for clearing
	200	in al, dx ; Read Interrupt Mask Register
	201	and al, ch ; Clear wanted bit
	202	out dx, al ; Write modified Interrupt Mask Register
	203	pop cx
[86]	204	.Return:
[33]	205	ret

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