System information

FUNCTION 17: SEARCH FOR FIRST

Entry Parameters:

RegisterC: 11H

Registers DE: FCB Address

Returned Value:

Search First scans the directory for a match with the file given by the FCB addressed by DE. The

value 255 (hexadecimal FF) is returned if the file is not found; otherwise, 0, 1, 2, or 3 is returned

indicating the file is present. When the file is found, the current DMA address is filled with the

record containing the directory entry, and the relative starting position is A * 32 (that is, rotate

the A register left 5 bits, or ADD A five times). Although not normally required for application

programs, the directory information can be extracted from the buffer at this position.

An ASCII question mark (63 decimal, 3F hexadecimal) in any position from fl through ex

matches the corresponding field of any directory entry on the default or auto-selected disk drive.

If the dr field contains an ASCII question mark, the auto disk select function is disabled and the

default disk is searched, with the search function returning any matched entry, allocated or free,

belonging to any user number. This latter function is not normally used by application programs,

but it allows complete flexibility to scan all current directory values. If the dr field is not a

question mark, the s2 byte is automatically zeroed.

5.2 Call Conventions CP/M Operating System Manual

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