Topic       : MC56001 Documentation
Author      : JAY Software
Version     : 1.0 (19/11/1997)
Subject     : Programming/Assembler
Nodes       : 152
Index Size  : 4106
HCP-Version : 4
Compiled on : Atari
@charset    : atarist
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View Ref-FileWAIT                        Wait for Interrupt

Operation:
    Disable clocks to the processor core and enter the WAIT processing
state.

Assembler Syntax:
    WAIT

Description:
    Enter the WAIT processing state. The internal clocks to the processor
core and memories are gated off, and all activity in the processor is
suspended until an unmasked interrupt occurs. The clock oscillator and
the internal I/O peripheral clocks remain active. If WAIT is executed
when an interrupt is pending, the interrupt will be processed; the effect
will be the same as if the processor never entered the WAIT state and
three NOPs followed the WAIT instruction. When an unmasked interrupt or
external (hardware) processor RESET occurs, the processor leave the WAIT
state and begins exception processing of the unmasked interrupt or RESET
condition. The BR/BG circuits remain active during the WAIT state. The WAIT
state is a low-power standby state. The processor always leave the WAIT
state in the T2 clock phase. Therefore, multiple processors may be
synchronized by having them all enter the WAIT state and then interrupting
them with a common interrupt.

Restrictions:
    A WAIT instruction cannot be used in a fast interrupt routine.
    A WAIT instruction cannot be the last instruction in a DO loop (at LA).
    A WAIT instruction cannot be repeated using REP instruction.

Condition Codes:
    The condition codes are not affected by this instruction.

Instruction Format:
    WAIT

Timing:     The WAIT instruction takes a minimum of 16 cycles to execute
when an internal interrupt is pending during the execution of the WAIT
instruction.

Memory:     1 program word