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source: xtideuniversalbios/trunk/Assembly_Library/Src/File/FileIO.asm@ 318

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Last change on this file since 318 was 293, checked in by krille_n_@…, 13 years ago

Commit 1/2 (Library, Configurators and Serial Server):

Changed Emulate.inc so that making 286 and 386 versions now works. Additionally, only one processor type define is needed in the makefile.
Minor optimizations.
Fixed spelling and did some cleaning.

File size: 7.3 KB

Rev	Line
[41]	1	; Project name : Assembly Library
	2	; Description : Functions for file access.
	3
	4	; Section containing code
	5	SECTION .text
	6
	7	;--------------------------------------------------------------------
	8	; FileIO_OpenWithPathInDSSIandFileAccessInAL
	9	; Parameters:
	10	; AL: FILE_ACCESS.(mode)
	11	; DS:SI: Ptr to NULL terminated path or file name
	12	; Returns:
	13	; AX: DOS error code if CF set
	14	; BX: File handle if CF cleared
	15	; CF: Clear if file opened successfully
	16	; Set if error
	17	; Corrupts registers:
	18	; AX, BX
	19	;--------------------------------------------------------------------
	20	ALIGN JUMP_ALIGN
	21	FileIO_OpenWithPathInDSSIandFileAccessInAL:
	22	xchg dx, si ; Path now in DS:DX
	23	mov ah, OPEN_EXISTING_FILE
	24	int DOS_INTERRUPT_21h
	25	xchg si, dx
[51]	26	mov bx, ax ; Copy file handle to BX
[41]	27	ret
	28
	29
	30	;--------------------------------------------------------------------
[66]	31	; FileIO_ReadDXCXbytesToDSSIusingHandleFromBX
	32	; Parameters:
	33	; BX: File handle
	34	; DX:CX: Number of bytes to read
	35	; DS:SI: Ptr to destination buffer
	36	; Returns:
	37	; AX: DOS error code if CF set
[293]	38	; CF: Clear if successful
[66]	39	; Set if error
	40	; Corrupts registers:
	41	; AX
	42	;--------------------------------------------------------------------
	43	ALIGN JUMP_ALIGN
	44	FileIO_ReadDXCXbytesToDSSIusingHandleFromBX:
	45	push bp
	46	mov bp, FileIO_ReadCXbytesToDSSIusingHandleFromBX
	47	call SplitLargeReadOrWritesToSmallerBlocks
	48	pop bp
	49	ret
	50
	51	;--------------------------------------------------------------------
[41]	52	; File position is updated so next read will start where
	53	; previous read stopped.
[133]	54	;
[41]	55	; FileIO_ReadCXbytesToDSSIusingHandleFromBX
	56	; Parameters:
	57	; BX: File handle
	58	; CX: Number of bytes to read
	59	; DS:SI: Ptr to destination buffer
	60	; Returns:
[293]	61	; AX: Number of bytes actually read if successful (0 if at EOF before call)
[41]	62	; DOS error code if CF set
[293]	63	; CF: Clear if successful
[41]	64	; Set if error
	65	; Corrupts registers:
	66	; Nothing
	67	;--------------------------------------------------------------------
	68	ALIGN JUMP_ALIGN
	69	FileIO_ReadCXbytesToDSSIusingHandleFromBX:
[51]	70	xchg dx, si ; DS:DX now points to destination buffer
[41]	71	mov ah, READ_FROM_FILE_OR_DEVICE
	72	int DOS_INTERRUPT_21h
	73	xchg si, dx
	74	ret
	75
	76
	77	;--------------------------------------------------------------------
[66]	78	; FileIO_WriteDXCXbytesFromDSSIusingHandleFromBX
	79	; Parameters:
	80	; BX: File handle
	81	; DX:CX: Number of bytes to write
	82	; DS:SI: Ptr to source buffer
	83	; Returns:
	84	; AX: DOS error code if CF set
[293]	85	; CF: Clear if successful
[66]	86	; Set if error
	87	; Corrupts registers:
	88	; AX
	89	;--------------------------------------------------------------------
	90	ALIGN JUMP_ALIGN
	91	FileIO_WriteDXCXbytesFromDSSIusingHandleFromBX:
	92	push bp
	93	mov bp, FileIO_WriteCXbytesFromDSSIusingHandleFromBX
	94	call SplitLargeReadOrWritesToSmallerBlocks
	95	pop bp
	96	ret
	97
	98	;--------------------------------------------------------------------
[41]	99	; File position is updated so next write will start where
	100	; previous write stopped.
[133]	101	;
[41]	102	; FileIO_WriteCXbytesFromDSSIusingHandleFromBX:
	103	; Parameters:
	104	; BX: File handle
	105	; CX: Number of bytes to write
	106	; DS:SI: Ptr to source buffer
	107	; Returns:
[293]	108	; AX: Number of bytes actually written if successful (EOF check)
[41]	109	; DOS error code if CF set
[293]	110	; CF: Clear if successful
[41]	111	; Set if error
	112	; Corrupts registers:
	113	; Nothing
	114	;--------------------------------------------------------------------
	115	ALIGN JUMP_ALIGN
	116	FileIO_WriteCXbytesFromDSSIusingHandleFromBX:
	117	xchg dx, si ; DS:DX now points to source buffer
	118	mov ah, WRITE_TO_FILE_OR_DEVICE
	119	int DOS_INTERRUPT_21h
	120	xchg si, dx
	121	ret
	122
	123
	124	;--------------------------------------------------------------------
[66]	125	; SplitLargeReadOrWritesToSmallerBlocks
	126	; Parameters:
	127	; BX: File handle
	128	; BP: Ptr to transfer function
	129	; DX:CX: Number of bytes to transfer
	130	; DS:SI: Ptr to transfer buffer
	131	; Returns:
	132	; AX: DOS error code if CF set
[293]	133	; CF: Clear if successful
[66]	134	; Set if error
	135	; Corrupts registers:
	136	; AX
	137	;--------------------------------------------------------------------
	138	ALIGN JUMP_ALIGN
	139	SplitLargeReadOrWritesToSmallerBlocks:
	140	push ds
	141	push si
	142	push dx
	143	push cx
	144
	145	xchg ax, cx ; DX:AX now holds bytes to transfer
	146	mov cx, SPLIT_SIZE_FOR_LARGE_TRANSFERS
	147	div cx ; AX = Number of full transfers
	148	push dx ; Bytes for last transfer
	149	test ax, ax
	150	jz SHORT .TransferRemainingBytes
	151	xchg dx, ax ; DX = Number of full transfers
	152
	153	ALIGN JUMP_ALIGN
	154	.TransferNextBytes:
[105]	155	call NormalizeDSSI
[66]	156	call bp ; Transfer function
	157	jc SHORT .ErrorOccurredDuringTransfer
[67]	158	add si, SPLIT_SIZE_FOR_LARGE_TRANSFERS
[66]	159	dec dx
	160	jnz SHORT .TransferNextBytes
	161	.TransferRemainingBytes:
	162	pop cx ; CX = Bytes for last transfer
	163	jcxz .ReturnErrorCodeInAX ; No remaining bytes
[105]	164	call NormalizeDSSI
[66]	165	call bp
	166	.ReturnErrorCodeInAX:
	167	pop cx
	168	pop dx
	169	pop si
	170	pop ds
	171	ret
	172	.ErrorOccurredDuringTransfer:
	173	pop cx ; Remove bytes for last transfer
	174	jmp SHORT .ReturnErrorCodeInAX
	175
[105]	176	;--------------------------------------------------------------------
	177	; NormalizeDSSI
	178	; Parameters
	179	; DS:SI: Ptr to normalize
	180	; Returns:
	181	; DS:SI: Normalized pointer
	182	; Corrupts registers:
	183	; Nothing
	184	;--------------------------------------------------------------------
	185	ALIGN JUMP_ALIGN
	186	NormalizeDSSI:
	187	push dx
	188	push ax
	189	NORMALIZE_FAR_POINTER ds, si, ax, dx
	190	pop ax
	191	pop dx
	192	ret
[66]	193
[105]	194
[66]	195	;--------------------------------------------------------------------
[51]	196	; FileIO_GetFileSizeToDXAXusingHandleFromBXandResetFilePosition:
	197	; Parameters:
	198	; BX: File handle
	199	; Returns:
	200	; DX:AX: Signed file size (if CF cleared)
	201	; AX: DOS error code (if CF set)
[293]	202	; CF: Clear if successful
[51]	203	; Set if error
	204	; Corrupts registers:
	205	; Nothing
	206	;--------------------------------------------------------------------
	207	ALIGN JUMP_ALIGN
	208	FileIO_GetFileSizeToDXAXusingHandleFromBXandResetFilePosition:
	209	push cx
	210
	211	; Get file size to DX:AX
	212	xor cx, cx
	213	xor dx, dx
	214	mov al, SEEK_FROM.endOfFile
	215	call FileIO_SeekFromOriginInALtoOffsetInDXAXusingHandleFromBX
	216	jc SHORT .ReturnFileError
	217	push dx
	218	push ax
	219
	220	; Reset file position
	221	xor dx, dx
	222	mov al, SEEK_FROM.startOfFile
	223	call FileIO_SeekFromOriginInALtoOffsetInDXAXusingHandleFromBX
	224	pop ax
	225	pop dx
	226
	227	.ReturnFileError:
	228	pop cx
	229	ret
	230
	231
	232	;--------------------------------------------------------------------
[133]	233	; FileIO_CloseUsingHandleFromBX
	234	; Parameters:
	235	; BX: File handle
	236	; Returns:
	237	; AX: DOS error code if CF set
	238	; CF: Clear if file closed successfully
	239	; Set if error
	240	; Corrupts registers:
	241	; AX
	242	;--------------------------------------------------------------------
	243	ALIGN JUMP_ALIGN
	244	FileIO_CloseUsingHandleFromBX:
	245	mov ah, CLOSE_FILE
	246	SKIP2B f ; cmp ax, <next instruction>
	247	; Fall to FileIO_SeekFromOriginInALtoOffsetInDXAXusingHandleFromBX
	248
	249
	250	;--------------------------------------------------------------------
[41]	251	; FileIO_SeekFromOriginInALtoOffsetInDXAXusingHandleFromBX:
	252	; Parameters:
	253	; AL: SEEK_FROM.(origin)
	254	; BX: File handle
[51]	255	; CX:DX: Signed offset to seek starting from AL
[41]	256	; Returns:
[51]	257	; DX:AX: New file position in bytes from start of file (if CF cleared)
	258	; AX: DOS error code (if CF set)
[293]	259	; CF: Clear if successful
[41]	260	; Set if error
	261	; Corrupts registers:
	262	; Nothing
	263	;--------------------------------------------------------------------
	264	FileIO_SeekFromOriginInALtoOffsetInDXAXusingHandleFromBX:
	265	mov ah, SET_CURRENT_FILE_POSITION
	266	int DOS_INTERRUPT_21h
	267	ret

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