Compile File Operations

File Operation Function)

3CH-	Create a file
3DH-	Open a file
3EH-	Close file
41 H-	Delete an object
43 H-	Read/set file attributes
45 H-	Copy file handle
46 H-	Redefinition file handle
4EH-	Find the first file
4FH-	Find the next file
56 H-	File Name Change

(1) function 3CH

	Function Description:	Create a new file with the specified file name. If the specified file already exists, set the length to 0. After the file is created, it is opened and its handle is returned.
	Entry parameters:	AH = 3CH DS: DX = specifies the address of the file name string (0 is the end mark of the string) CX = file attributes (these flags can be combined) Bit 0 = 1 -- read-only Bit 2 = 1 -- System Bit 5 = 1 -- Archive Bit 1 = 1 -- implicit Bit 3 = 1 -- volume label Do not retain other bits, and set them to 0.
	Exit parameters:	CF = 0 -- created successfully, AX = file handle. Otherwise, AX = Error Code (03 H, 04H or 05 H). For details, see error code table.

(2) function 3DH

	Function Description:	Open the specified drive, path, and file name, and return the file handle.
	Entry parameters:	AH = 3DH DS: DX = indicates the string of the file (0 is the end mark of the string) AL is the open method: Bit 0 ~ 2 000-read-only mode 001-write mode 010-read/write mode Bit 3 Reserved. The value is 0. 4-digit ~ 6 Sharing Mode 000-compatibility mode 001-do not share 010-write rejected 011-read denied 100-do not reject any operation Bits 7 Inheritance flag-0/1: the sub-process inherits or does not inherit the handle
	Exit parameters:	CF = 0 -- open successfully. AX = file handle. Otherwise, AX = Error Code (02 H, 03 H, 04 H, 05H, or 0CH). For details, see error code table.

(3) function 3EH

	Function Description:	Close the file with the specified handle
	Entry parameters:	AH = 3EH BX = file handle
	Exit parameters:	CF = 0 -- close successful; otherwise, AX = Error Code (06 H). For more information, see error code table.

(4) 41 H Functions

	Function Description:	Deletes a specified object.
	Entry parameters:	AH = 41 H DS: dx = address of the file name string
	Exit parameters:	Cf = 0 -- the deletion is successful. Otherwise, Ax = Error Code (02 h, 03h or 05 h). For details, see error code table.

(5) 43 H Functions

	Function Description:	Reads or sets attributes of a specified object.
	Entry parameters:	Ah = 43 H BX = file handle DS: dx = address of the file name string Al = 00 h/01 H -- Read/set file attributes Cx = file attributes: Bit 0 = 1 -- read-only Bit 1 = 1 -- implicit Bit 2 = 1 -- System Bit 3 = 1 -- volume label Bit 5 = 1 -- Archive Do not retain other bits, and set them to 0.
	Exit parameters:	Cf = 0 -- close successful, Cx = File Attribute. Otherwise, Ax = Error Code (01 H, 02 h, 03h or 05 h). For details, see error code table.

(6) 45 H Functions

	Function Description:	Copy the current handle that opens a device or file. The handle corresponds to the same location of the device or file.
	Entry parameters:	Ah = 45 h BX = file handle to be copied
	Exit parameters:	Cf = 0 -- copied successfully. Ax = new handle. Otherwise, Ax = Error Code (H or 06 h). For details, see error code table.

(7) 46 H Functions

	Function Description:	Specify two handles and direct the second handle to the first handle, that is, the second handle is redirected.
	Entry parameters:	Ah = 46 h BX = file or device handle Cx = file handle to be redirected
	Exit parameters:	Cf = 0 -- redirection succeeded. Otherwise, Ax = Error Code (H or 06 h). For details, see error code table.

(8) function 4EH

	Function Description:	Obtain the first file that matches the specified file name.
	Entry parameters:	Ah = 4eh DS: dx = string of the given file name Cx = file attributes used for search:   Bit 0 = 1 -- Read-Only bit 1 = 1 -- implicit Bit 2 = 1 -- System bit 3 = 1 -- volume label Bit 4 = 1 -- directory bit 5 = 1 -- Archive Do not retain other bits, and set them to 0.
	Exit parameters:	Cf = 1 -- operation failed, Ax = Error Code (02 h, 03h or 12 h). For details, see error code table. Otherwise, the operation is successful. DTA (Disk transfer area) enter data as follows: Byte 00 ~ 14 h Retained 15 h in bytes Matching file attributes Byte 16 ~ 17 h Compressed file name Byte 18 ~ 19 h Compressed file date Byte 1A ~ 1dh File Size Bytes 1E ~ 2ah File Name string

(9) function 4FH

	Function Description:	After the 21h function is interrupted and 4eh is used successfully, search for the next file name.
	Entry parameters:	Ah = 4fh Al = Returned Code
	Exit parameters:	Cf = 1 -- operation failed, Ax = Error Code (12 h). For more information, see error code table. Otherwise, the operation is successful. The data in DTA is shown in the previous function 4eh.

(10) 56 H Functions

	Function Description:	File Name Change
	Entry parameters:	Ah = 56 h DS: dx = string address of the current file name ES: di = new file name string address
	Exit parameters:	Cf = 0 -- the operation is successful. Otherwise, the ax = Error Code (02 h, 03 h, 05 h, and 11 h) can be found in the error code table.

(11) function 57 H

	Function Description:	Read/set file date and time
	Entry parameters:	Ah = 57 H BX = file handle Read Date and Time Al = 00 h Set Date and Time Al = 01 H Cx = Time (0f ~ 0bh: hour, 0ah ~ 05 h: minute, 04h ~ 00 h: 2 seconds) DX = Date (0f ~ 09 h: Year (relative to 1980), 08h ~ 05 h: Month, 04h ~ 00 h: Day)
	Exit parameters:	CF = 1 -- operation failed, AX = Error Code (01 H, 06 H). For its meaning, see error code table. Otherwise, if the file information is read, CX = Time, DX = Date

(12) function 5AH

	Function Description:	Create temporary files
	Entry parameters:	AH = 5AH DS: DX = path name address CX = file attributes (bits can be combined), which are defined as follows: Bit 0 = 1 read-only Bit 3-4 = 0 Reserved Bit 1 = 1 implicit Bit 5 = 1 Archive Bit 2 = 1 System 6-15 = 0 Reserved
	Exit parameters:	CF = 0 -- operation successful, AX = file handle, DS: DX = complete path file address; otherwise, AX = Error Code (03 H, 04H or 05 H ), for more information, see error code table.

(13) function 5BH

	Function Description:	Create a new file
	Entry parameters:	AH = 5BH DS: DX = path name address CX = file attributes (bits can be combined), which are defined as follows:   Bit 0 = 1 Read-Only 4 = 0 Retained Bit 1 = 1 Implicit Bit 5 = 1 Archive Bit 2 = 1 System 6-15 = 0 Retained Bit 3 = 1 Volume label
	Exit parameters:	CF = 0 -- operation succeeded. AX = file handle. Otherwise, AX = Error Code (03 H, 04 H, 05H, or 50 H). For details, see error code table.

(14) 67 H Functions

	Function Description:	Set the number of file handles (maximum number of files)
	Entry parameters:	AH = 67 H BX = number of handles
	Exit parameters:	CF = 0 -- operation succeeded; otherwise, AX = Error Code. For more information, see error code table.

(15) function 6CH

	Function Description:	Extended file opening (opening, creating, or replacing files)
	Entry parameters:	Ah = 6ch Al = 00 h DS: SI = path name address BX = open mode Bits 2 ~ 0 000-read-only 001-write only 010-read and write Bit 3 Reserved (0) 6-digit ~ 4 000-compatible 001-read/write denied 010-write denied 011-read 100 denied-no operation is denied Bits 7 0-the sub-process inherits the handle; 1-The sub-process does not inherit the handle. 12-bit ~ 8 Reserved (0) Bit 13 Fatal error handler, 0-Execute int 24 h; otherwise, the error code is returned to the Process Bit 14 Write method: 0-write buffer, 1-write files directly Digit 15 Reserved (0) Cx = file attributes   Bit 0 = 1 read-only Bit 4 = 0 Reserved Bit 1 = 1 implicit Bit 5 = 1 Archive Bit 2 = 1 System 6-15 = 0 Reserved Bit 3 = 1 volume label DX = open flag   Bit 3 ~ 0 0-open failed, 1-open file, 2-replace File Bits 7 ~ 4 0-open failed, 1-Create File 15-bit ~ 8 0-Reserved
	Exit parameters:	Cf = 1 -- operation failed, Ax = Error Code. For more information, see error code table. Otherwise, Ax = file handle Cx = 1 -- file exists, open it = 2 -- the file does not exist.

 

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