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source: xtideuniversalbios/trunk/XTIDE_Universal_BIOS/Src/VariablesAndDPTs/FindDPT.asm @ 521

Last change on this file since 521 was 521, checked in by aitotat@…, 11 years ago

Changes to XTIDE Universal BIOS:

Hopefully fixed problems with recent changes to AH=00h.
Timeout error code is no longer displayed when trying to boot from floppy drive.

File size: 9.6 KB

Rev	Line
[150]	1	; Project name : XTIDE Universal BIOS
[3]	2	; Description : Functions for finding Disk Parameter Table.
	3
[376]	4	;
	5	; XTIDE Universal BIOS and Associated Tools
	6	; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2012 by XTIDE Universal BIOS Team.
	7	;
	8	; This program is free software; you can redistribute it and/or modify
	9	; it under the terms of the GNU General Public License as published by
	10	; the Free Software Foundation; either version 2 of the License, or
	11	; (at your option) any later version.
	12	;
	13	; This program is distributed in the hope that it will be useful,
	14	; but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	; GNU General Public License for more details.
	17	; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
	18	;
	19
[3]	20	; Section containing code
	21	SECTION .text
	22
	23	;--------------------------------------------------------------------
[262]	24	; Checks if drive is handled by this BIOS, and return DPT pointer.
[3]	25	;
[294]	26	; FindDPT_ForDriveNumberInDL
[3]	27	; Parameters:
[262]	28	; DL: Drive number
[3]	29	; DS: RAMVARS segment
	30	; Returns:
[262]	31	; CF: Cleared if drive is handled by this BIOS
	32	; Set if drive belongs to some other BIOS
	33	; DI: DPT Pointer if drive is handled by this BIOS
	34	; Zero if drive belongs to some other BIOS
[3]	35	; Corrupts registers:
[262]	36	; Nothing
[150]	37	;--------------------------------------------------------------------
	38	ALIGN JUMP_ALIGN
[294]	39	FindDPT_ForDriveNumberInDL:
[262]	40	xchg di, ax ; Save the contents of AX in DI
	41
[294]	42	;
[262]	43	; Check Our Hard Disks
	44	;
[433]	45	mov ax, [RAMVARS.wFirstDrvAndCount] ; Drive count to AH, First number to AL
[262]	46	add ah, al ; One past last drive to AH
	47
[258]	48	%ifdef MODULE_SERIAL_FLOPPY
[262]	49	cmp dl, ah ; Above last supported?
	50	jae SHORT .HardDiskNotHandledByThisBIOS
[294]	51
[262]	52	cmp dl, al ; Below first supported?
	53	jae SHORT .CalcDPTForDriveNumber
	54
[294]	55	ALIGN JUMP_ALIGN
	56	.HardDiskNotHandledByThisBIOS:
[262]	57	;
	58	; Check Our Floppy Disks
[294]	59	;
[262]	60	call RamVars_UnpackFlopCntAndFirstToAL
	61	js SHORT .DiskIsNotHandledByThisBIOS
[294]	62
[277]	63	cbw ; Always 0h (no floppy drive covered above)
	64	adc ah, al ; Add in first drive number and number of drives
	65
[262]	66	cmp ah, dl ; Check second drive if two, first drive if only one
	67	jz SHORT .CalcDPTForDriveNumber
	68	cmp al, dl ; Check first drive in all cases, redundant but OK to repeat
[294]	69	jnz SHORT .DiskIsNotHandledByThisBIOS
[262]	70	%else
[294]	71	cmp dl, ah ; Above last supported?
[262]	72	jae SHORT .DiskIsNotHandledByThisBIOS
[294]	73
[262]	74	cmp dl, al ; Below first supported?
[294]	75	jb SHORT .DiskIsNotHandledByThisBIOS
[258]	76	%endif
[262]	77	; fall-through to CalcDPTForDriveNumber
[150]	78
	79	;--------------------------------------------------------------------
	80	; Finds Disk Parameter Table for drive number.
[294]	81	; Not intended to be called except by FindDPT_ForDriveNumberInDL
[150]	82	;
[262]	83	; CalcDPTForDriveNumber
[150]	84	; Parameters:
	85	; DL: Drive number
	86	; DS: RAMVARS segment
[294]	87	; DI: Saved copy of AX from entry at FindDPT_ForDriveNumberInDL
[150]	88	; Returns:
	89	; DS:DI: Ptr to DPT
[262]	90	; CF: Clear
[150]	91	; Corrupts registers:
[3]	92	; Nothing
	93	;--------------------------------------------------------------------
	94	ALIGN JUMP_ALIGN
[262]	95	.CalcDPTForDriveNumber:
[150]	96	push dx
[3]	97
[258]	98	%ifdef MODULE_SERIAL_FLOPPY
[433]	99	mov ax, [RAMVARS.wFirstDrvAndCount]
[294]	100
[258]	101	test dl, dl
	102	js .harddisk
	103
	104	call RamVars_UnpackFlopCntAndFirstToAL
	105	add dl, ah ; add in end of hard disk DPT list, floppies start immediately after
[294]	106
	107	ALIGN JUMP_ALIGN
[258]	108	.harddisk:
	109	sub dl, al ; subtract off beginning of either hard disk or floppy list (as appropriate)
	110	%else
	111	sub dl, [RAMVARS.bFirstDrv] ; subtract off beginning of hard disk list
	112	%endif
[262]	113
[294]	114	.CalcDPTForNewDrive:
[150]	115	mov al, LARGEST_DPT_SIZE
[294]	116
[150]	117	mul dl
[294]	118	add ax, BYTE RAMVARS_size ; Clears CF (will not overflow)
[3]	119
[150]	120	pop dx
[262]	121
	122	xchg di, ax ; Restore AX from entry at FindDPT_ForDriveNumber, put DPT pointer in DI
[150]	123	ret
	124
[294]	125	ALIGN JUMP_ALIGN
	126	.DiskIsNotHandledByThisBIOS:
[259]	127	;
[262]	128	; Drive not found...
	129	;
	130	xor ax, ax ; Clear DPT pointer
[294]	131	stc ; Is not supported by our BIOS
	132
[262]	133	xchg di, ax ; Restore AX from save at top
[259]	134	ret
	135
[271]	136
[259]	137	;--------------------------------------------------------------------
[521]	138	; FindDPT_MasterOrSingleForIdevarsOffsetInDL
[271]	139	; Parameters:
	140	; DL: Offset to IDEVARS to search for
	141	; DS: RAMVARS segment
	142	; Returns:
	143	; DS:DI: Ptr to first DPT with same IDEVARS as in DL
	144	; CF: Clear if wanted DPT found
	145	; Set if DPT not found, or no DPTs present
	146	; Corrupts registers:
	147	; SI
	148	;--------------------------------------------------------------------
[521]	149	FindDPT_MasterOrSingleForIdevarsOffsetInDL:
[271]	150	mov si, IterateFindFirstDPTforIdevars ; iteration routine (see below)
	151	jmp SHORT FindDPT_IterateAllDPTs ; look for the first drive on this controller, if any
	152
	153	;--------------------------------------------------------------------
[521]	154	; FindDPT_SlaveForIdevarsOffsetInDL
	155	; Parameters:
	156	; DL: Offset to IDEVARS to search for
	157	; DS: RAMVARS segment
	158	; Returns:
	159	; DS:DI: Ptr to second DPT with same IDEVARS as in DL
	160	; CF: Clear if wanted DPT found
	161	; Set if DPT not found, or no DPTs present
	162	; Corrupts registers:
	163	; SI
	164	;--------------------------------------------------------------------
	165	FindDPT_SlaveForIdevarsOffsetInDL:
	166	mov si, IterateFindSecondDPTforIdevars ; iteration routine (see below)
	167	jmp SHORT FindDPT_IterateAllDPTs ; look for the second drive on this controller, if any
	168
	169	;--------------------------------------------------------------------
	170	; Iteration routines for FindDPT_MasterOrSingleForIdevarsOffsetInDL and
	171	; FindDPT_SlaveForIdevarsOffsetInDL, for use with IterateAllDPTs
[294]	172	;
[271]	173	; Returns when DPT is found on the controller with Idevars offset in DL
	174	;
[521]	175	; IterateFindSecondDPTforIdevars
[271]	176	; IterateFindFirstDPTforIdevars
	177	; DL: Offset to IDEVARS to search from DPTs
	178	; DS:DI: Ptr to DPT to examine
	179	; Returns:
	180	; CF: Clear if wanted DPT found
	181	; Set if wrong DPT
	182	;--------------------------------------------------------------------
[521]	183	IterateFindSecondDPTforIdevars:
	184	call IterateFindFirstDPTforIdevars
	185	jc SHORT IterateFindFirstDPTforIdevars.done ; Wrong controller
	186
	187	; We have found DPT for Master Drive,
	188	; next DPT is for slave drive or master for another controller
	189	add di, BYTE LARGEST_DPT_SIZE
	190	; Fall to IterateFindFirstDPTforIdevars
	191
[294]	192	IterateFindFirstDPTforIdevars:
[271]	193	cmp dl, [di+DPT.bIdevarsOffset] ; Clears CF if matched
	194	je .done
	195	stc ; Set CF for not found
[294]	196	.done:
[271]	197	ret
	198
	199
	200	;--------------------------------------------------------------------
[262]	201	; Finds pointer to first unused Disk Parameter Table.
	202	; Should only be used before DetectDrives is complete (not valid after this time).
[3]	203	;
[262]	204	; FindDPT_ForNewDriveToDSDI
[3]	205	; Parameters:
	206	; DS: RAMVARS segment
	207	; Returns:
[262]	208	; DS:DI: Ptr to first unused DPT
[3]	209	; Corrupts registers:
[262]	210	; AX
[3]	211	;--------------------------------------------------------------------
[262]	212	ALIGN JUMP_ALIGN
	213	FindDPT_ForNewDriveToDSDI:
	214	push dx
[294]	215
[262]	216	%ifdef MODULE_SERIAL_FLOPPY
	217	mov dx, [RAMVARS.wDrvCntAndFlopCnt]
	218	add dl, dh
	219	%else
	220	mov dl, [RAMVARS.bDrvCnt]
	221	%endif
[294]	222
[262]	223	jmp short FindDPT_ForDriveNumberInDL.CalcDPTForNewDrive
[3]	224
[152]	225	;--------------------------------------------------------------------
[233]	226	; IterateToDptWithFlagsHighInBL
[152]	227	; Parameters:
	228	; DS:DI: Ptr to DPT to examine
[294]	229	; BL: Bit(s) to test in DPT.bFlagsHigh
[152]	230	; Returns:
[262]	231	; CF: Clear if wanted DPT found
	232	; Set if wrong DPT
[152]	233	; Corrupts registers:
	234	; Nothing
	235	;--------------------------------------------------------------------
	236	ALIGN JUMP_ALIGN
[294]	237	IterateToDptWithFlagsHighInBL:
	238	test [di+DPT.bFlagsHigh], bl ; Clears CF
[262]	239	jnz SHORT .ReturnRightDPT
	240	stc
[294]	241	.ReturnRightDPT:
[3]	242	ret
	243
	244	;--------------------------------------------------------------------
[233]	245	; FindDPT_ToDSDIforSerialDevice
[161]	246	; Parameters:
	247	; DS: RAMVARS segment
	248	; Returns:
	249	; DS:DI: Ptr to DPT
	250	; CF: Set if wanted DPT found
	251	; Cleared if DPT not found
	252	; Corrupts registers:
[203]	253	; SI
[161]	254	;--------------------------------------------------------------------
[265]	255	%ifdef MODULE_SERIAL
[294]	256	ALIGN JUMP_ALIGN
	257	FindDPT_ToDSDIforSerialDevice:
[233]	258	mov bl, FLGH_DPT_SERIAL_DEVICE
	259	; fall-through
[265]	260	%endif
[294]	261
[233]	262	;--------------------------------------------------------------------
	263	; FindDPT_ToDSDIforFlagsHigh
	264	; Parameters:
	265	; DS: RAMVARS segment
	266	; BL: Bit(s) to test in DPT.bFlagsHigh
	267	; Returns:
	268	; DS:DI: Ptr to DPT
	269	; CF: Set if wanted DPT found
	270	; Cleared if DPT not found
	271	; Corrupts registers:
	272	; SI
	273	;--------------------------------------------------------------------
[489]	274	%ifdef MODULE_IRQ
[161]	275	ALIGN JUMP_ALIGN
[489]	276	FindDPT_ToDSDIforFlagsHighInBL:
	277	%endif
[233]	278	mov si, IterateToDptWithFlagsHighInBL
[161]	279	; Fall to IterateAllDPTs
	280
	281	;--------------------------------------------------------------------
[3]	282	; Iterates all Disk Parameter Tables.
	283	;
[271]	284	; FindDPT_IterateAllDPTs
[3]	285	; Parameters:
[152]	286	; AX,BX,DX: Parameters to callback function
	287	; CS:SI: Ptr to callback function
[262]	288	; Callback routine should return CF=clear if found
[152]	289	; DS: RAMVARS segment
[3]	290	; Returns:
[152]	291	; DS:DI: Ptr to wanted DPT (if found)
[258]	292	; If not found, points to first empty DPT
[262]	293	; CF: Clear if wanted DPT found
	294	; Set if DPT not found, or no DPTs present
[3]	295	; Corrupts registers:
[150]	296	; Nothing unless corrupted by callback function
[3]	297	;--------------------------------------------------------------------
	298	ALIGN JUMP_ALIGN
[271]	299	FindDPT_IterateAllDPTs:
[3]	300	push cx
[258]	301
	302	mov di, RAMVARS_size ; Point DS:DI to first DPT
[294]	303	eMOVZX cx, [RAMVARS.bDrvCnt]
[262]	304	jcxz .NotFound ; Return if no drives
[294]	305
[3]	306	ALIGN JUMP_ALIGN
	307	.LoopWhileDPTsLeft:
	308	call si ; Is wanted DPT?
[262]	309	jnc SHORT .Found ; If so, return
	310	add di, BYTE LARGEST_DPT_SIZE ; Point to next DPT
[258]	311	loop .LoopWhileDPTsLeft
[262]	312
[3]	313	ALIGN JUMP_ALIGN
[262]	314	.NotFound:
	315	stc
	316
	317	ALIGN JUMP_ALIGN
	318	.Found:
[3]	319	pop cx
	320	ret

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