# BITCHANGE

Updated: 10/19/2021, 9:29:48 PM
Created: 10/19/2021, 9:29:48 PM
Last Updated By: Kevin Munoz
Read Time: 1 minute(s)

# Description

BITCHANGE toggles the state of a specified bit in the local bit table, and returns the original value of the bit. It takes the general from:

BITCHANGE(table_no)
1

Where:

table_no specifies the position in the table of the bit to be changed.

For each process, it maintains a unique table of 128 bits (numbered 1 to 128) and treats each bit in the table as a two-state flag - the value returned will always be zero or one.

BITCHANGE returns the value of the bit before it was changed. You can therefore check and set (or reset) a flag in one step. BITCHANGE also provides some special functions if you use one of the following table_no values:

  • -1 toggles (enables/disables) the BREAK key Inhibit bit.
  • -2 toggles (enables/disables) the Command Level Restart feature.
  • -3 toggles (enables/disables) the Break/End Restart feature.

An example of use is as:

OLD.VAL = BITCHANGE (100)
CRT OLD.VAL
1
2

If bit 100 in the table is zero, it sets to one and displays zero; the reverse will apply if set to one..

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