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Set of Apple II Hard Drive Images
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CPM
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CPMPDL.txt
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2020-08-13
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630b
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23 lines
; SUB TO READ PADDLE 0 INTO REG A
; DEMO OF 6502 SUBROUTINE CALLING FROM CPM
;
Z$CPU EQU 0F3DEH
A$VEC EQU 0F3D0H
A$ACC EQU 0F045H
A$XREG EQU 0F046H
PREAD EQU 0FB1EH
;
PDL XRA A ;CLEAR A
STA A$XREG ;PADDLE # 0 TO BE READ
LXI H,PREAD ;GET ADDR OF SUBROUTINE
SHLD A$VEC ;STORE IT FOR 6502
LHLD Z$CPU ;GET SOFTCARD ADDR
MOV M,A ;WRITE CAUSES EXEC OF 6502 SUB
;
;EXECUTION RESUMES HERE AFTER 6502 RTS
;
LDA A$ACC ;A HAS PADDLE VALUE
RET
;
END