System information

FUNCTION 32: SET/GET USER CODE

Entry Parameters:

User Code (set)

Returned Value:

(no value)

An application program can change or interrogate the currently active user number by calling

Function 32. If register E = 0FFH, the value of the current user number is returned in register A,

where the value is in the range of 0 to 15. If register E is not 0FFH, the current user number is

changed to the value of E, modulo 16.

FUNCTION 33: READ RANDOM

Entry Parameters:

RegisterC: 21H

Returned Value:

The Read Random function is similar to the sequential file read operation of previous releases,

except that the read operation takes place at a particular record number, selected by the 24-bit

value constructed from the 3-byte field following the FCB (byte positions r0 at 33, r1 at 34, and

r2 at 35). The user should note that the sequence of 24 bits is stored with least significant byte

first (r0), middle byte next (r1), and high byte last (r2). CP/M does not reference byte r2, except

in computing the size of a file (Function 35). Byte r2 must be zero, however, since a nonzero

value indicates overflow past the end of file.

5.2 Call Conventions CP/M Operating System Manual

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