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source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/Initialization/Interrupts.asm@ 212

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Last change on this file since 212 was 181, checked in by krille_n_@…, 13 years ago

Changes to all parts of the project:

Size optimizations.
Added a define (EXCLUDE_FROM_XTIDECFG) to exclude unused library code from XTIDECFG.
Tried to minimize time spent with interrupts disabled.
Some minor attempts to improve speed (reordering instructions etc).
Tried to improve readability, did some cleanup and fixed some errors in comments.

File size: 7.2 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
[97]	45	jc SHORT .InitializeInt19h
[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
[97]	48	; Fall to .InitializeInt19h
[33]	49
	50	;--------------------------------------------------------------------
[97]	51	; .InitializeInt19h
[33]	52	; Parameters:
	53	; DS: RAMVARS segment
	54	; ES: BDA and Interrupt Vector segment (zero)
	55	; Returns:
	56	; Nothing
	57	; Corrupts registers:
	58	; BX, SI
[86]	59	;--------------------------------------------------------------------
[97]	60	.InitializeInt19h:
[152]	61	mov bx, BIOS_BOOT_LOADER_INTERRUPT_19h
[33]	62	mov si, Int19hMenu_BootLoader
[97]	63	call Interrupts_InstallHandlerToVectorInBXFromCSSI
	64	; Fall to .InitializeHardwareIrqHandlers
[33]	65
	66	;--------------------------------------------------------------------
[97]	67	; .InitializeHardwareIrqHandlers
[33]	68	; Parameters:
	69	; ES: BDA and Interrupt Vector segment (zero)
	70	; Returns:
	71	; Nothing
	72	; Corrupts registers:
	73	; BX, CX, DX, SI, DI
[86]	74	;--------------------------------------------------------------------
[97]	75	.InitializeHardwareIrqHandlers:
[33]	76	call RamVars_GetIdeControllerCountToCX
	77	mov di, ROMVARS.ideVars0 ; CS:SI points to first IDEVARS
	78	.IdeControllerLoop:
	79	eMOVZX bx, BYTE [cs:di+IDEVARS.bIRQ]
	80	add di, BYTE IDEVARS_size ; Increment to next controller
	81	call .InstallLowOrHighIrqHandler
	82	loop .IdeControllerLoop
[86]	83	.Return:
	84	ret ; This ret is shared with .InstallLowOrHighIrqHandler
[33]	85
	86	;--------------------------------------------------------------------
	87	; .InstallLowOrHighIrqHandler
	88	; Parameters:
	89	; BX: IRQ number, 0 if IRQ disabled
	90	; ES: BDA and Interrupt Vector segment (zero)
	91	; Returns:
	92	; Nothing
	93	; Corrupts registers:
	94	; BX, SI
[86]	95	;--------------------------------------------------------------------
[33]	96	.InstallLowOrHighIrqHandler:
[86]	97	test bl, bl
	98	jz SHORT .Return ; IRQ not used
[33]	99	cmp bl, 8
[86]	100	jb SHORT .InstallLowIrqHandler
[162]	101	; Fall to .InstallHighIrqHandler
[33]	102
	103	;--------------------------------------------------------------------
	104	; .InstallHighIrqHandler
	105	; Parameters:
	106	; BX: IRQ number (8...15)
	107	; ES: BDA and Interrupt Vector segment (zero)
	108	; Returns:
	109	; Nothing
	110	; Corrupts registers:
	111	; BX, SI
[86]	112	;--------------------------------------------------------------------
[97]	113	.InstallHighIrqHandler:
[152]	114	add bx, BYTE HARDWARE_IRQ_8_INTERRUPT_70h - 8 ; Interrupt vector number
[150]	115	mov si, IdeIrq_InterruptServiceRoutineForIrqs8to15
[33]	116	jmp SHORT Interrupts_InstallHandlerToVectorInBXFromCSSI
	117
	118	;--------------------------------------------------------------------
	119	; .InstallLowIrqHandler
	120	; Parameters:
	121	; BX: IRQ number (0...7)
	122	; ES: BDA and Interrupt Vector segment (zero)
	123	; Returns:
	124	; Nothing
	125	; Corrupts registers:
	126	; BX, SI
[86]	127	;--------------------------------------------------------------------
[33]	128	.InstallLowIrqHandler:
[152]	129	add bx, BYTE HARDWARE_IRQ_0_INTERRUPT_08h ; Interrupt vector number
[150]	130	mov si, IdeIrq_InterruptServiceRoutineForIrqs2to7
[33]	131	; Fall to Interrupts_InstallHandlerToVectorInBXFromCSSI
	132
	133
	134	;--------------------------------------------------------------------
	135	; Interrupts_InstallHandlerToVectorInBXFromCSSI
	136	; Parameters:
	137	; BX: Interrupt vector number (for example 13h)
	138	; ES: BDA and Interrupt Vector segment (zero)
	139	; CS:SI: Ptr to interrupt handler
	140	; Returns:
	141	; Nothing
	142	; Corrupts registers:
	143	; BX
[86]	144	;--------------------------------------------------------------------
[33]	145	Interrupts_InstallHandlerToVectorInBXFromCSSI:
[123]	146	eSHL_IM bx, 2 ; Shift for DWORD offset
[33]	147	mov [es:bx], si ; Store offset
	148	mov [es:bx+2], cs ; Store segment
	149	ret
	150
	151
	152	;--------------------------------------------------------------------
	153	; Interrupts_UnmaskInterruptControllerForDriveInDSDI
	154	; Parameters:
	155	; DS:DI: Ptr to DPT
	156	; Returns:
	157	; Nothing
	158	; Corrupts registers:
	159	; AX, BX, DX
	160	;--------------------------------------------------------------------
	161	Interrupts_UnmaskInterruptControllerForDriveInDSDI:
[150]	162	eMOVZX bx, BYTE [di+DPT.bIdevarsOffset]
[33]	163	mov al, [cs:bx+IDEVARS.bIRQ]
[86]	164	test al, al
	165	jz SHORT .Return ; Interrupts disabled
[33]	166	cmp al, 8
[86]	167	jb SHORT .UnmaskLowIrqController
[162]	168	; Fall to .UnmaskHighIrqController
[33]	169
	170	;--------------------------------------------------------------------
	171	; .UnmaskHighIrqController
	172	; Parameters:
	173	; AL: IRQ number (8...15)
	174	; Returns:
	175	; Nothing
	176	; Corrupts registers:
	177	; AX, DX
	178	;--------------------------------------------------------------------
[97]	179	.UnmaskHighIrqController:
[33]	180	sub al, 8 ; Slave interrupt number
[152]	181	mov dx, SLAVE_8259_IMR
[33]	182	call .ClearBitFrom8259MaskRegister
	183	mov al, 2 ; Master IRQ 2 to allow slave IRQs
	184	; Fall to .UnmaskLowIrqController
	185
	186	;--------------------------------------------------------------------
	187	; .UnmaskLowIrqController
	188	; Parameters:
	189	; AL: IRQ number (0...7)
	190	; Returns:
	191	; Nothing
	192	; Corrupts registers:
	193	; AX, DX
	194	;--------------------------------------------------------------------
	195	.UnmaskLowIrqController:
[152]	196	mov dx, MASTER_8259_IMR
[33]	197	; Fall to .ClearBitFrom8259MaskRegister
	198
	199	;--------------------------------------------------------------------
	200	; .ClearBitFrom8259MaskRegister
	201	; Parameters:
	202	; AL: 8259 interrupt index (0...7)
	203	; DX: Port address to Interrupt Mask Register
	204	; Returns:
	205	; Nothing
	206	; Corrupts registers:
	207	; AX
	208	;--------------------------------------------------------------------
	209	.ClearBitFrom8259MaskRegister:
	210	push cx
	211	xchg ax, cx ; IRQ index to CL
	212	mov ch, 1 ; Load 1 to be shifted
	213	shl ch, cl ; Shift bit to correct position
	214	not ch ; Invert to create bit mask for clearing
	215	in al, dx ; Read Interrupt Mask Register
	216	and al, ch ; Clear wanted bit
	217	out dx, al ; Write modified Interrupt Mask Register
	218	pop cx
[86]	219	.Return:
[33]	220	ret

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