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source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/CreateDPT.asm@ 168

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Last change on this file since 168 was 162, checked in by krille_n_@…, 13 years ago

Changes to all parts of the project:

Size optimizations, mostly by excluding code from the BIOS.
Cleaned the source a bit, fixed spelling and grammar mistakes.

File size: 7.6 KB

Rev	Line
[99]	1	; Project name : XTIDE Universal BIOS
[3]	2	; Description : Functions for creating Disk Parameter Table.
	3
	4	; Section containing code
	5	SECTION .text
	6
	7	;--------------------------------------------------------------------
	8	; Creates new Disk Parameter Table for detected hard disk.
	9	; Drive is then fully accessible using any BIOS function.
	10	;
	11	; CreateDPT_FromAtaInformation
	12	; Parameters:
	13	; BH: Drive Select byte for Drive and Head Register
	14	; ES:SI: Ptr to 512-byte ATA information read from the drive
	15	; CS:BP: Ptr to IDEVARS for the controller
	16	; DS: RAMVARS segment
	17	; ES: BDA Segment
	18	; Returns:
	19	; DL: Drive number for new drive
	20	; DS:DI: Ptr to Disk Parameter Table (if succesfull)
	21	; CF: Cleared if DPT created successfully
	22	; Set if any error
	23	; Corrupts registers:
[99]	24	; AX, BX, CX, DH
[3]	25	;--------------------------------------------------------------------
	26	CreateDPT_FromAtaInformation:
[150]	27	call FindDPT_ForNewDriveToDSDI
[99]	28	; Fall to .InitializeDPT
[3]	29
	30	;--------------------------------------------------------------------
[99]	31	; .InitializeDPT
[3]	32	; Parameters:
	33	; BH: Drive Select byte for Drive and Head Register
	34	; DS:DI: Ptr to Disk Parameter Table
	35	; CS:BP: Ptr to IDEVARS for the controller
	36	; Returns:
[150]	37	; Nothing
[3]	38	; Corrupts registers:
[150]	39	; AX
[3]	40	;--------------------------------------------------------------------
[99]	41	.InitializeDPT:
[150]	42	mov [di+DPT.bIdevarsOffset], bp ; IDEVARS must start in first 256 bytes of ROM
	43	; Fall to .StoreDriveSelectAndDriveControlByte
[3]	44
	45	;--------------------------------------------------------------------
[150]	46	; .StoreDriveSelectAndDriveControlByte
[3]	47	; Parameters:
	48	; BH: Drive Select byte for Drive and Head Register
	49	; DS:DI: Ptr to Disk Parameter Table
	50	; ES:SI: Ptr to 512-byte ATA information read from the drive
	51	; CS:BP: Ptr to IDEVARS for the controller
	52	; Returns:
[99]	53	; Nothing
[3]	54	; Corrupts registers:
	55	; AX
	56	;--------------------------------------------------------------------
[150]	57	.StoreDriveSelectAndDriveControlByte:
	58	mov al, bh
	59	and ax, BYTE FLG_DRVNHEAD_DRV ; AL now has Master/Slave bit
	60	cmp [cs:bp+IDEVARS.bIRQ], ah ; Interrupts enabled?
	61	jz SHORT .StoreFlags ; If not, do not set interrupt flag
[158]	62	or al, FLGL_DPT_ENABLE_IRQ
[150]	63	.StoreFlags:
	64	mov [di+DPT.wFlags], ax
[99]	65	; Fall to .StorePCHS
[3]	66
	67	;--------------------------------------------------------------------
[99]	68	; .StorePCHS
[3]	69	; Parameters:
	70	; BH: Drive Select byte for Drive and Head Register
	71	; DS:DI: Ptr to Disk Parameter Table
	72	; ES:SI: Ptr to 512-byte ATA information read from the drive
	73	; CS:BP: Ptr to IDEVARS for the controller
	74	; Returns:
[99]	75	; AX: P-CHS cylinders
	76	; BL: P-CHS heads
	77	; BH: P-CHS sectors
[3]	78	; Corrupts registers:
	79	; Nothing
	80	;--------------------------------------------------------------------
[99]	81	.StorePCHS:
	82	mov al, FLG_DRVPARAMS_USERCHS ; User specified CHS?
[3]	83	call AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
[99]	84	jnz SHORT .GetUserSpecifiedPCHS
	85	call AtaID_GetPCHS ; Get from ATA information
	86	jmp SHORT .StorePCHStoDPT
[3]	87
[99]	88	.GetUserSpecifiedPCHS:
[3]	89	call AccessDPT_GetPointerToDRVPARAMStoCSBX
	90	mov ax, [cs:bx+DRVPARAMS.wCylinders]
[99]	91	mov bx, [cs:bx+DRVPARAMS.wHeadsAndSectors]
[3]	92
[99]	93	.StorePCHStoDPT:
[150]	94	mov [di+DPT.wPchsCylinders], ax
	95	mov [di+DPT.wPchsHeadsAndSectors], bx
[99]	96	; Fall to .StoreLCHS
[3]	97
	98	;--------------------------------------------------------------------
[99]	99	; .StoreLCHS
[3]	100	; Parameters:
[99]	101	; AX: P-CHS cylinders
	102	; BL: P-CHS heads
[3]	103	; DS:DI: Ptr to Disk Parameter Table
	104	; ES:SI: Ptr to 512-byte ATA information read from the drive
[160]	105	; CS:BP: Ptr to IDEVARS for the controller
[3]	106	; Returns:
[99]	107	; Nothing
[3]	108	; Corrupts registers:
[99]	109	; AX, BX, CX
[3]	110	;--------------------------------------------------------------------
[99]	111	.StoreLCHS:
	112	xor bh, bh ; BX = P-CHS Heads (1...16)
	113	xor cx, cx
[3]	114	.ShiftLoop:
[99]	115	cmp ax, 1024 ; Need to shift?
	116	jbe SHORT .LimitHeadsTo255 ; If not, return
	117	inc cx ; Increment shift count
	118	shr ax, 1 ; Halve cylinders
	119	shl bx, 1 ; Double heads
[3]	120	jmp SHORT .ShiftLoop
	121
[150]	122	.LimitHeadsTo255: ; DOS does not support drives with 256 heads
	123	rcr bh, 1 ; Set CF if 256 heads
	124	sbb bl, 0 ; Decrement to 255 if 256 heads
	125	or [di+DPT.wFlags], cl
	126	mov [di+DPT.bLchsHeads], bl
[99]	127	; Fall to .StoreAddressing
[3]	128
	129	;--------------------------------------------------------------------
[99]	130	; .StoreAddressing
[3]	131	; Parameters:
	132	; DS:DI: Ptr to Disk Parameter Table
	133	; ES:SI: Ptr to 512-byte ATA information read from the drive
[160]	134	; CS:BP: Ptr to IDEVARS for the controller
[3]	135	; Returns:
[99]	136	; Nothing
[3]	137	; Corrupts registers:
[150]	138	; AX, BX
[3]	139	;--------------------------------------------------------------------
[99]	140	.StoreAddressing:
[150]	141	; Check if L-CHS addressing should be used
	142	cmp WORD [di+DPT.wPchsCylinders], 1024 ; L-CHS possible? (no translation needed)
	143	jbe SHORT .StoreBlockMode ; If so, nothing needs to be changed
	144
	145	; Check if P-CHS addressing should be used
	146	mov al, FLG_DRVPARAMS_USERCHS ; User specified CHS?
	147	call AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
	148	jnz SHORT .StorePCHSaddressing
[3]	149	test WORD [es:si+ATA1.wCaps], A2_wCaps_LBA
[150]	150	jz SHORT .StorePCHSaddressing ; Use P-CHS since LBA not supported
	151
	152	; LBA needs to be used. Check if 48-bit LBA is supported
[3]	153	test WORD [es:si+ATA6.wSetSup83], A6_wSetSup83_LBA48
[150]	154	jz SHORT .StoreLBA28addressing ; Use LBA-28 since LBA-48 not supported
	155	or BYTE [di+DPT.wFlags], ADDRESSING_MODE_LBA48<<ADDRESSING_MODE_FIELD_POSITION
[99]	156	.StoreLBA28addressing:
[150]	157	or BYTE [di+DPT.wFlags], ADDRESSING_MODE_LBA28<<ADDRESSING_MODE_FIELD_POSITION
[99]	158	jmp SHORT .StoreBlockMode
	159	.StorePCHSaddressing:
[150]	160	or BYTE [di+DPT.wFlags], ADDRESSING_MODE_PCHS<<ADDRESSING_MODE_FIELD_POSITION
[99]	161	; Fall to .StoreBlockMode
[3]	162
	163	;--------------------------------------------------------------------
[99]	164	; .StoreBlockMode
[3]	165	; Parameters:
	166	; DS:DI: Ptr to Disk Parameter Table
	167	; ES:SI: Ptr to 512-byte ATA information read from the drive
[160]	168	; CS:BP: Ptr to IDEVARS for the controller
[3]	169	; Returns:
[99]	170	; Nothing
[3]	171	; Corrupts registers:
[150]	172	; Nothing
[3]	173	;--------------------------------------------------------------------
[99]	174	.StoreBlockMode:
[150]	175	cmp BYTE [es:si+ATA1.bBlckSize], 1 ; Max block size in sectors
	176	jbe SHORT .BlockModeTransfersNotSupported
[158]	177	or BYTE [di+DPT.bFlagsHigh], FLGH_DPT_BLOCK_MODE_SUPPORTED
[150]	178	.BlockModeTransfersNotSupported:
	179	; Fall to .StoreDeviceSpecificParameters
[3]	180
	181	;--------------------------------------------------------------------
[150]	182	; .StoreDeviceSpecificParameters
[3]	183	; Parameters:
	184	; DS:DI: Ptr to Disk Parameter Table
	185	; ES:SI: Ptr to 512-byte ATA information read from the drive
[160]	186	; CS:BP: Ptr to IDEVARS for the controller
[3]	187	; Returns:
[99]	188	; Nothing
[3]	189	; Corrupts registers:
[150]	190	; AX, BX, CX, DX
[3]	191	;--------------------------------------------------------------------
[150]	192	.StoreDeviceSpecificParameters:
	193	call Device_FinalizeDPT
[99]	194	; Fall to .StoreDriveNumberAndUpdateDriveCount
[3]	195
	196	;--------------------------------------------------------------------
[99]	197	; .StoreDriveNumberAndUpdateDriveCount
[3]	198	; Parameters:
	199	; DS:DI: Ptr to Disk Parameter Table
	200	; ES:SI: Ptr to 512-byte ATA information read from the drive
[160]	201	; CS:BP: Ptr to IDEVARS for the controller
[3]	202	; ES: BDA Segment
	203	; Returns:
	204	; DL: Drive number for new drive
[162]	205	; CF: Always cleared
[3]	206	; Corrupts registers:
	207	; Nothing
	208	;--------------------------------------------------------------------
[99]	209	.StoreDriveNumberAndUpdateDriveCount:
[150]	210	mov dl, [es:BDA.bHDCount]
	211	or dl, 80h ; Set bit 7 since hard disk
[3]	212
[150]	213	inc BYTE [RAMVARS.bDrvCnt] ; Increment drive count to RAMVARS
	214	inc BYTE [es:BDA.bHDCount] ; Increment drive count to BDA
[3]	215
[150]	216	cmp BYTE [RAMVARS.bFirstDrv], 0 ; First drive set?
	217	ja SHORT .AllDone ; If so, return
	218	mov [RAMVARS.bFirstDrv], dl ; Store first drive number
[162]	219	clc
[150]	220	.AllDone:
[3]	221	ret

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