mirror of
https://github.com/nathanriggs/AppleIIAsm-Collection.git
synced 2024-12-03 18:49:28 +00:00
875dd80998
- fixed a bunch of bugs - separated common and stdio libraries - commenting upgrades - created min versions of each library
95 lines
2.7 KiB
Plaintext
95 lines
2.7 KiB
Plaintext
*
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*``````````````````````````````*
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* GPBX :: GET PADDLE BUTTON X *
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* *
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* GETS STATE OF PADDLE BUTTON *
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* SPECIFIED AND RET 0, 1 IN A *
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*- -*
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* CLOBBERS: *
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* *
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* FLAGS: ???----- REG: A-YM *
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*- -*
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* CYCLES: ??? *
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* SIZE: *
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*- -*
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* USAGE: *
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* LDA #>(ADDRESS) *
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* PHA *
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* LDA #<(ADDRESS) *
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* PHA *
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* JSR GPBX *
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* *
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* --- WHERE: *
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* *
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* BUTTON 0 = $C061 (PB0) *
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* BUTTON 1 = $CO62 (PB1) *
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* BUTTON 2 - $C063 (PB2) *
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* BUTTON 3 = $C060 (PB3) *
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*- -*
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* ENTRY *
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* *
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* TOP OF STACK *
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* *
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* LOW BYTE OF RETURN ADDRESS *
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* HI BYTE OF RETURN ADDRESS *
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* LOW BYTE OF PDL BTN ADDRESS *
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* HI BYTE OF PDL BTN ADDRESS *
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*- -*
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* EXIT *
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* *
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* TOP OF STACK *
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* *
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* LOW BYTE OF RETURN ADDRESS *
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* HI BYTE OF RETURN ADDRESS *
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* *
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* A = 1 IF PRESSED, 0 IF NOT *
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* X = UNCHANGED *
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* Y = GARBAGE *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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* CHANGE THIS LATER TO ACCEPT ALL BUTTONS, 0-4
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*
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GBPX
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*
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** SAVE RETURN ADDRESS
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*
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PLA
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STA :RETADR
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PLA
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STA :RETADR+1
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*
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** GET PARAMETER
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*
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PLA
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STA ADDR1 ; ZERO PAGE
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PLA
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STA ADDR1+1
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*
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*
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LDY #$00
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LDA (ADDR1),Y ; IF BTN = PUSHED
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BMI :1
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JMP :0
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:1
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LDY #$01 ; BTN PUSHED;A=1
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JMP :EXIT
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:0
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LDY #$00 ; BTN NOT PUSHED;A=0
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*
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:EXIT
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*
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** RESTORE RETURN ADDRESS
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*
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LDA :RETADR+1
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PHA
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LDA :RETADR
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PHA
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*
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TYA ; BTN FLAG MOVE TO A
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RTS
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*
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** DATA
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*
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:RETADR DS 2
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*
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