mirror of
https://github.com/nathanriggs/AppleIIAsm-Collection.git
synced 2024-12-03 18:49:28 +00:00
91 lines
2.2 KiB
Plaintext
91 lines
2.2 KiB
Plaintext
*
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*``````````````````````````````*
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* PRNSTR :: PRINT INDEXED STR *
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*- -*
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* PRINT A STRING WITH LENGTH *
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* THAT PRECEDES START OF STR *
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*- -*
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* CLOBBERS: *
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* *
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* FLAGS: ????---- REG: AXYM *
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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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* *
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* LDA #>STR ; STRING ADDRESS *
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* PHA *
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* LDA #<STR *
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* PHA *
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* JSR PRNSTR *
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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 STRING ADDRESS *
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* HIGH BYTE OF STRING 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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* .Y = LOW BYTE STRING ADDR *
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* .X = HI BYTE STRING ADDR *
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* .A = STRING LENGTH *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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PRNSTR
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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 PARAMETERS
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*
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PLA
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STA ADDR1 ; ADDRESS OF STRING
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PLA
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STA ADDR1+1
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*
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LDY #0
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LDA (ADDR1),Y ; GET STRING LENGTH
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STA :S1LEN
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:LP
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INY
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LDA (ADDR1),Y ; GET CHARACTER
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JSR SCOUT1 ; PRINT CHARACTER TO SCREEN
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CPY :S1LEN ; IF Y < LENGTH
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BNE :LP
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; LOOP; ELSE
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LDY #0
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LDA (ADDR1),Y
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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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LDY #0
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LDA (ADDR1),Y ; STRING LENGTH IN A
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LDY ADDR1
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LDX ADDR1+1 ; ADDRESS IN Y,X
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*
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RTS
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*
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** DATA
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*
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:S1LEN DS 1
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*
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