CYASM ASSEMBLER USER'S GUIDE VERSION 1.77

PUSH Push Register into Data Stack PUSH
Syntax
Operation
PUSH A dsp ← dsp - 1
[dsp] ← acc
PUSH X dsp ← dsp - 1
[dsp] ← X
Description:
Decrement the data stack pointer. Push the contents of the designated register onto the
data stack.
Condition Flags:
CF:
ZF:
Carry flag unaffected.
Zero flag unaffected.
Source Machine Code Cycles
Format Opcode Operand
PUSH A 2Dh 5
PUSH X 2Eh 5
RET Return RET
Syntax:
RET
Operation: psp ← psp - 2
pc ← [psp]
Description:
Pop two bytes off of the program stack into the program counter.
Condition Flags: Depends on A or B versions CPUs
A version:
CF: Carry restored to the value that was pushed onto the program stack.
ZF: Zero restored to the value that was pushed onto the program stack.
B version:
CF: Carry unchanged by this instruction.
ZF: Zero unchanged by this instruction.
Source Opcode Machine Code Cycles
Format Operand Comments
RET 3FH A: flags restored 8
RET 3FH B: flags returned 8
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