The 80x86 IBM PC and Compatible Computers- P20: Praised by experts for its clarity and topical breadth, this visually appealing, one-stop source on PCs uses an easy-to-understand, step-by-step approach to teaching the fundamentals of 80x86 assembly language programming and PC architecture. Offering users a fun, hands-on learning experience, it uses the Debug utility to show what action the instruction performs, then provides a sample program to show its application. | AH Function of INT 21H Search for first match FIND FIRST Additional Call Registers Result Registers DS DX address of ASCIIZ file specification CX attribute to use in search Carry flag 0 if successful 1 if failed AX error code Note The filename should contain one or more wildcard characters. Before this call a previous call to interrupt 21 function 1 AH must set the address of the DTA. If a matching filename is found the current DTA will be filled in as follows Bytes 0 - 20 reserved by DOS for use on subsequent search calls 21 attribute found 22-23 file time 24 - 25 file date 26 - 27 file size least significant word 28 - 29 file size most significant word 30 - 42 ASCIIZ file specification 4F Search for next filename match FIND NEXT Additional Call Registers Result Registers None Carry flag 0 if successful 1 if failed AX error code Note The current DTA must be filled in by a previous interrupt 21 4EH or 4FH call. The DTA will be filled in as outlined on interrupt 21 function 4E. 50 Reserved 51 Reserved 52 Reserved 53 Reserved 54 Get verify state Additional Call Registers Result Registers__ None AL 00 if verify OFF 01 if verify ON Note The state of the verify flag is changed via interrupt 21 function 2EH. 55 Reserved Please purchase PDF Split-Merge on to remove this watermark. SECTION DOS 21H INTERRUPTS 915 AH Function of INT 21H 56 Rename file Additional Call Registers_ DS DX address of old ASCIIZ filename specification ES DI address of new ASCIIZ filename specification Result Registers_ Carry flag 0 if successful 1 if failed AX 2 if file not found 3 if path or file not found 5 if access denied 11H if different device in new name Note If a drive specification is used it must be the same in the old and new filename specifications. However the directory name may be different allowing a move and rename in one operation. 57 Get set file date and time Additional Call Registers AL 00 to get 01 to set BX file .
