Microsoft BASIC for 6502 – Original Source Code (1978)
looks like there is a <i>PHP</i> intruction.<p><pre><code>    TABER: PHP			;REMEMBER IF SPC OR TAB FUNCTION.
	   JSR	GTBYTC		;GET VALUE INTO ACCX.
	   CMPI	41
	   BNE	SNERR4
</code></pre>
also it appears right in the middle<p><pre><code>    FRETMP: STWD	INDEX		;GET LENGTH FOR LATER.
	    JSR		FRETMS		;FREE UP THE TEMPORARY DESC.
	    PHP				;SAVE CODES.
	    LDYI	0		;PREP TO GET STUFF.
	    LDADY	INDEX		;GET COUNT AND
</code></pre>
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