PHP Instruction (Push Processor Status Register)

Pushes the processor status register onto the stack.

PHP Overloads

Opcode	Syntax	Addressing mode	Bytes	Cycles	Notes
08	PHP	Stack	1	3

Flag changes

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This instruction does not change the status flags.

Explanation

The PHP instruction pushes the contents of the status flags onto the stack. Regardless of the processor’s operating mode, it always pushes an 8-bit value.

Examples

Preserving register widths in a subroutine

Sub:
    PHP             ; save the caller's flags (including register widths)
    REP #$30        ; this routine works in 16 bits
    ...
    PLP             ; restore the caller's register widths
    RTS

This makes the routine work correctly whatever widths the caller uses.