mirror of
https://github.com/nathanriggs/AppleIIAsm-Collection.git
synced 2024-11-24 07:31:09 +00:00
16c1731e54
- bugfixes - implemented required library - commenting updates - .min of every routine
854 lines
22 KiB
Plaintext
854 lines
22 KiB
Plaintext
*
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JMP STRINGSX
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*
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*-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=*
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* *
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* STRINGS ROUTINE LIBRARY *
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* *
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* AUTHOR: NATHAN RIGGS *
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* CONTACT: NATHAN.RIGGS@ *
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* OUTLOOK.COM *
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* *
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* VERSION: 0.2.0 *
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* DATE: 30-OCT-2018 *
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* ASSEMBLER: MERLIN 8 PRO *
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* OS: DOS 3.3 *
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* LICENSE: APACHE 2.0 *
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* *
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* THIS IS A STANDARD LIBRARY *
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* FOR STRING MANIPULATION. *
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* *
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*------------------------------*
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* *
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* LIST OF ROUTINES *
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* *
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* STRCOMP : STRING COMPARE *
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* STRCAT : CONCATENATE STRING *
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* PRNSTR : PRINT STRING *
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* NUM2STR : NUMBER TO STRING *
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* STR2NUM : STRING TO NUMBER *
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* *
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*=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-*
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*
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*``````````````````````````````*
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* STRCMP :: STRING COMPARE *
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*- -*
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* COMPARE TWO STRINGS AND *
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* DETERMINE IF THEY ARE *
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* IDENTICAL; IF NOT, DETERMINE *
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* WHICH IS THE SHORTEST AND *
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* WHICH IS THE LONGEST. *
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* *
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* Z FLAG = 1 IF IDENTICAL *
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* Z FLAG = 0 IF NOT *
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* CARRY = 1 IF STR2 > STR1 LEN *
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* CARRY = 0 IF STR1 > STR2 LEN *
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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 #>STR1 *
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* PHA *
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* LDA #<STR1 *
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* PHA *
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* LDA #>STR2 *
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* PHA *
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* LDA #<STR2 *
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* PHA *
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* JSR STRCMP *
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* *
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* STR1 STR "STRING1 " *
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* STR2 STR "ZTRING2" *
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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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* STRING 2 ADDRESS LOW BYTE *
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* STRING 2 ADDRESS HI BYTE *
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* STRING 1 ADDRESS LOW BYTE *
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* STRING 1 ADDRESS HI BYTE *
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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 = LENGTH OF STRING 2 *
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* .X = LENGTH OF STRING 1 *
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* .A = CLOBBERED; TRASH *
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*- -*
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* ADAPTED FROM LEVANTHAL AND *
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* WINTHROP'S /6502 ASSEMBLY *
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* LANGUAGE ROUTINES/. MAY NOT *
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* FALL UNDER APACHE 2.0 UNTIL *
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* SUBSTANTIALLY ALTERED. *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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STRCMP
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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 ADDR2
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PLA
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STA ADDR2+1
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PLA
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STA ADDR1
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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 LENGTH OF STRING 1
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CMP (ADDR2),Y
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BCC :BEGCMP ; IF STRING 2 IS SHORTER THEN
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LDA (ADDR2),Y ; USE ITS LENGTH INSTEAD
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*
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** COMPARE THE STRINGS THROUGH THE
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** LENGTH OF THE SHORTER STRING
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*
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:BEGCMP
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TAX ; X IS LENGTH OF SHORTER STRING
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BEQ :TSTLEN ; BR IF LENGTH IS 0
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LDY #1 ; POINT AT FIRST CHAR OF STRINGS
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:CMPLP
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LDA (ADDR1),Y
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CMP (ADDR2),Y
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BNE :EXIT ; BR IF CHARS NOT EQUAL
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; Z,C WILL BE PROPERLY SET
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; OR CLEARED
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; ELSE
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INY ; NEXT CHAR
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DEX ; DECREMENT COUNTER
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BNE :CMPLP ; CONTINUE UNTIL ALL BYTES PAIRED
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*
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* THE 2 STRINGS ARE EQUAL TO LENGTH OF THE SHORTER
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* SO USE LENGTHS AS BASIS FOR SETTING THE FLAGS
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*
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:TSTLEN
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LDY #0 ; COMPARE LENGTHS
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LDA (ADDR1),Y
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CMP (ADDR2),Y ; SET OR CLEAR THE FLAGS
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*
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** Z FLAG = 1 IF STRINGS IDENTICAL
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** Z FLAG = 0 IF NOT IDENTICAL
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** CARRY = 0 IF STR2 LENGTH > STR1 LENGTH
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** CARRY = 1 IF STR1 LENGTH >= STR2 LENGTH
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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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LDY #0
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LDA (ADDR1),Y ; GET STR1 LENGTH
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TAX ; RETURN IN X
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LDA (ADDR2),Y ; STR2 LENGTH
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TAY ; RETURN IN Y
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*
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RTS
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*
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*``````````````````````````````*
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* STRCAT :: STRING CONCATENATE *
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*- -*
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* CONCATENATE TWO STRINGS INTO *
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* A SINGLE STRING STORE WHERE *
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* THE FIRST STRING IS LOCATED. *
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* ADDITIONALLY COPIES CONCAT'D *
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* STRING TO [RETURN]. *
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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 #>CATSTR *
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* PHA *
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* LDA #<CATSTR *
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* PHA *
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* LDA #>CATSTR2 *
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* PHA *
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* LDA #<CATSTR2 *
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* PHA *
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* LDA #7 ; MAX SIZE OF CAT *
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* PHA *
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* JSR STRCAT *
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* *
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* CATSTR STR "ABC" *
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* BLANK STR " " *
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* CATSTR2 STR "DEF" *
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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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* MAXIMUM LENGTH OF CONCAT STR *
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* LOW BYTE OF STR2 ADDRESS *
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* HIGH BYTE OF STR2 ADDRESS *
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* LOW BYTE OF STR1 ADDRESS *
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* HIGH BYTE OF STR1 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 = CLOBBERED; TRASH *
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* .X = LENGTH OF FINAL STRING *
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* .A = 1 IF OVERFLOW, 0 IF NO *
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* [RETURN] = CONCAT'D STRING *
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* [RETLEN] = LENGTH OF NEW STR *
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*- -*
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* ADAPTED FROM LEVANTHAL AND *
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* WINTHROP'S /6502 ASSEMBLY *
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* LANGUAGE ROUTINES/. *
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*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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STRCAT
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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 :MLEN ; MAXIMUM CONCAT LENGTH
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*
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PLA
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STA ADDR2 ; STRING 1 ADDRESS
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PLA ; IN ZERO PAGE
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STA ADDR2+1
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PLA
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STA ADDR1 ; STRING 2 ADDRESS
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PLA ; IN ZERO PAGE
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STA ADDR1+1
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*
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** DETERMINE WHERE TO START
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*
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LDY #0
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LDA (ADDR1),Y ; GET CUR LGTH OF S1, STORE
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STA :S1LEN
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STA :S1IND
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INC :S1IND ; START CONCAT AT END OF S1
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LDA (ADDR2),Y ; GET LENGTH OF S2, STORE
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STA :S2LEN
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LDA #1
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STA :S2IND ; START CONCAT AT BEGIN OF S2
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*
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** DETERMINE NUMBER OF CHAR
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*
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LDA :S2LEN ; GET S2 LENGTH
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CLC
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ADC :S1LEN ; ADD TO LENGTH OF S1
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STA :S3LEN ; STORE CONCAT LENGTH
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BCS :TOOLONG ; BR IF LENGTH > 255
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CMP :MLEN ; CHECK AGAINST MAX LENGTH
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BEQ :LENOK ; BR IF LENGTH < MAX
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BCC :LENOK
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*
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** RESULTING STRING WILL BE TOO LONG SO
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** INDICATE A STRING OVERFLOW, __SOVF = 0FF
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** SET NUMBER OF CHARS TO CONCAT = MLEN - S1LEN
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** SET LENGTH OF STRING 1 TO MAX LENGTH
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*
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:TOOLONG
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LDA #$0FF
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STA :SOVF ; INDICATE OVERFLOW
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LDA :MLEN
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SEC
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SBC :S1LEN
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BCC :EXIT
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; EXIT IF MLEN < S1LEN
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STA :SCNT ; ORIG STR WAS TOO LONG
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LDA :MLEN
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STA :S1LEN ; SET STR1 LENGTH TO MAX
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JMP :DOCAT
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*
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** RESULTING LENGTH DOES NOT EXCEED MAX
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** LENGTH OF STRING 1 = S1LEN + S2LEN
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** INDICATE NO OVERFLOW, __SOVF = 0
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** SET NUM OF CHARS TO CONCAT TO LENGTH OF STR 2
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*
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:LENOK
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STA :S1LEN
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LDA #0 ; SAVE SUM OF 2 LENGTHS
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STA :SOVF ; INDICATE NO OVERFLOW
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LDA :S2LEN
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STA :SCNT ; COUNT = LENGTH OF STRING 2
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*
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** CONCAT STRINGS
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*
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:DOCAT
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LDA :SCNT
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BEQ :EXIT ; EXIT IF NO BYTES LEFT
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*
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:CATLP
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LDY :S2IND
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LDA (ADDR2),Y ; GET NEXT BYTE FROM S2
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LDY :S1IND
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STA (ADDR1),Y ; MOVE IT TO END OF STR 1
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INC :S1IND ;INC STRING 1 INDEX
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INC :S2IND ; INC STRING 2 INDEX
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DEC :SCNT ; DECREMENT COUNTER
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BNE :CATLP ; CONT UNTIL __SCNT = 0
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*
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:EXIT
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*
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** UPDATE STRING1 LENGTH
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*
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LDA :S1LEN
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LDY #0
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STA (ADDR1),Y
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LDA :SOVF
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ROR A
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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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** COPY TO [RETURN]
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*
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LDY #0
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LDA (ADDR1),Y ; LENGTH OF STRING
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STA RETLEN
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LDA #1
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:RLP
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LDA (ADDR1),Y
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STA RETURN,Y
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CPY RETLEN
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INY
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BNE :RLP
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LDA RETLEN
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LDY #0
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STA (ADDR1),Y
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*
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LDX :S3LEN ; RETURN FINAL LENGTH
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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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:S3LEN DS 1
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:S1LEN DS 1
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:S1IND DS 1
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:S2LEN DS 1
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:S2IND DS 1
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:MLEN DS 1
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:SCNT DS 1
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:SOVF DS 1
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*
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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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*``````````````````````````````*
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* NUM2STR :: NUMBER TO STRING *
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*- -*
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* CONVERTS A 16-BIT NUMBER TO *
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* ITS STRING EQUIVALENT. *
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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 #>11111 ; VALUE TO *
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* PHA ; CONVERT *
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* LDA #<11111 *
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* PHA *
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* JSR NUM2STR *
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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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* LO BYTE VALUE TO CONVERT *
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* HI BYTE VALUE TO CONVERT *
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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 = COUNTER; TRASH *
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* .X = COUNTER; TRASH *
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* .A = LOW BYTE OF RET ADDR *
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* *
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* [RETURN] = STRING VALUE *
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* [RETLEN] = LENGTH OF STRING *
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*- -*
|
|
* ADAPTED FROM LEVANTHAL AND *
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|
* WINTHROP'S /6502 ASSEMBLY *
|
|
* LANGUAGE ROUTINES/. *
|
|
*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
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*
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NUM2STR
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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 :VALSTR
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PLA
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STA :VALSTR+1
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*
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STA :NGFLAG
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BPL :GETBP ; BR IF VAL IS POS
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LDA #0
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SEC
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SBC :VALSTR
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STA :VALSTR
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LDA #0
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SBC :VALSTR+1
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STA :VALSTR+1
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*
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:GETBP
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LDA #<RETURN
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STA ADDR1 ; ADDRESS TO STORE STRING
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LDA #>RETURN+1
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STA ADDR1+1
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LDA #0 ; SET BUFFER TO EMPTY
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LDY #0
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STA (ADDR1),Y ; BUFFER(0) = 0
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*
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** CONVERT VAL TO STRING
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*
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:CNVERT
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*
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** VALUE = VALUE DIV 10
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** MOD10 = VALUE MOD 10
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*
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LDA #0
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STA :MOD10
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|
STA :MOD10+1
|
|
LDX #16
|
|
CLC ; CLEAR CARRY
|
|
*
|
|
:DVLOOP
|
|
ROL :VALSTR ; SHIFT CARRY INTO DIVBIT 0
|
|
ROL :VALSTR+1 ; WHICH WILL BE THE QUOTIENT
|
|
ROL :MOD10 ; + SHIFT DIV AT SAME TIME
|
|
ROL :MOD10+1
|
|
*
|
|
** A,Y = DIVIDEND - DIVISOR
|
|
*
|
|
SEC
|
|
LDA :MOD10
|
|
SBC #10
|
|
TAY ; SAVE LOWB IN REG Y
|
|
LDA :MOD10+1
|
|
SBC #0 ; SUBTRACT CARRY
|
|
BCC :DECCNT ; BR IF DEND < DIVISOR
|
|
STY :MOD10 ; ELSE
|
|
STA :MOD10+1 ; NXT BIT OF Q IS A ONE AND SET
|
|
; DIVIDEND = DEND - DIVISOR
|
|
:DECCNT
|
|
DEX
|
|
BNE :DVLOOP
|
|
ROL :VALSTR ; SHIFT IN LAST CARRY FOR Q
|
|
ROL :VALSTR+1
|
|
*
|
|
** CONCAT NEXT CHAR
|
|
*
|
|
:CONCH
|
|
LDA :MOD10
|
|
CLC
|
|
ADC #$B0
|
|
*
|
|
** ADC #'0' ; CONVERT 0..9 TO ASCII 0-9
|
|
*
|
|
JSR :CONCAT
|
|
*
|
|
** IF VALUE <> 0 THEN CONTINUE
|
|
*
|
|
LDA :VALSTR
|
|
ORA :VALSTR+1
|
|
BNE :CNVERT ; BR IF VALUE != 0
|
|
*
|
|
:EXIT
|
|
LDA :NGFLAG
|
|
BPL :POS ; BR IF ORIG VAL POS
|
|
LDA #173 ; ELSE
|
|
JSR :CONCAT ; PUT A MINUS SIGN IN FRONT
|
|
*
|
|
:POS
|
|
*
|
|
** RESTORE RETURN ADDRESS
|
|
*
|
|
LDA RETADR+1
|
|
PHA
|
|
LDA RETADR
|
|
PHA
|
|
*
|
|
RTS ; RETURN
|
|
*
|
|
********************************
|
|
* CONCAT SUBROUTINE
|
|
********************************
|
|
*
|
|
:CONCAT
|
|
PHA ; SAVE CHAR ON STACK
|
|
*
|
|
** MOVE BUFFER RIGHT ONE CHAR
|
|
*
|
|
LDY #0
|
|
LDA (ADDR1),Y ; GET CURRENT LENGTH
|
|
TAY
|
|
BEQ :EXITMR ; BR IF LENGTH=0
|
|
*
|
|
:MVELP
|
|
LDA (ADDR1),Y ; GET NEXT CHAR
|
|
INY
|
|
STA (ADDR1),Y ; STORE IT
|
|
DEY
|
|
DEY
|
|
BNE :MVELP ; CONT UNTIL DONE
|
|
*
|
|
:EXITMR
|
|
PLA ; GET CHAR BACK FROM STACK
|
|
LDY #1
|
|
STA (ADDR1),Y ; STORE THE CHAR
|
|
LDY #0
|
|
LDA (ADDR1),Y ; GET LENGTH BYTE
|
|
CLC
|
|
ADC #1 ; INC LENGTH BY ONE
|
|
STA (ADDR1),Y ; UPDATE LENGTH
|
|
*
|
|
RTS
|
|
*
|
|
** DATA
|
|
*
|
|
:NGFLAG DS 1
|
|
:VALSTR DS 2
|
|
:MOD10 DS 2
|
|
*
|
|
*``````````````````````````````*
|
|
* STR2NUM :: STRING TO NUMBER *
|
|
*- -*
|
|
* CONVERTS A STRING TO THE *
|
|
* EQUIVALENT 16BIT NUMBER. *
|
|
*- -*
|
|
* CLOBBERS: *
|
|
* *
|
|
* FLAGS: ????---- REG: AXYM *
|
|
*- -*
|
|
* CYCLES: ??? *
|
|
* SIZE: *
|
|
*- -*
|
|
* USAGE: *
|
|
* *
|
|
* LDA #>$300 ; STRING ADDR *
|
|
* PHA *
|
|
* LDA #<$300 *
|
|
* PHA *
|
|
* JSR STR2NUM *
|
|
*- -*
|
|
* ENTRY *
|
|
* *
|
|
* TOP OF STACK *
|
|
* *
|
|
* LOW BYTE OF RETURN ADDRESS *
|
|
* HI BYTE OF RETURN ADDRESS *
|
|
* LO BYTE OF STRING ADDRESS *
|
|
* HI BYTE OF STRING ADDRESS *
|
|
*- -*
|
|
* EXIT *
|
|
* *
|
|
* TOP OF STACK *
|
|
* *
|
|
* LOW BYTE OF RETURN ADDRESS *
|
|
* HI BYTE OF RETURN ADDRESS *
|
|
* *
|
|
* .Y = LO BYTE OF NUMBER *
|
|
* .X = HI BYTE OF NUMBER *
|
|
* .A = LOW BYTE OF RET ADDR *
|
|
* *
|
|
* [RETURN] = NUMBER VALUE WORD *
|
|
* [RETLEN] = 2 (NUM OF BYTES) *
|
|
*- -*
|
|
* ADAPTED FROM LEVANTHAL AND *
|
|
* WINTHROP'S /6502 ASSEMBLY *
|
|
* LANGUAGE ROUTINES/. *
|
|
*,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,*
|
|
*
|
|
STR2NUM
|
|
*
|
|
** SAVE RETURN ADDRESS
|
|
*
|
|
PLA
|
|
STA RETADR
|
|
PLA
|
|
STA RETADR+1
|
|
*
|
|
** GET PARAMETERS
|
|
*
|
|
PLA
|
|
STA ADDR1 ; ADRESS OF STRING
|
|
PLA ; TO CNVERT
|
|
STA ADDR1+1
|
|
*
|
|
** INITIALIZE
|
|
*
|
|
LDY #0
|
|
LDA (ADDR1),Y
|
|
TAX ; GET LENGITH; TO REGX
|
|
LDA #1
|
|
STA :NINDEX ; INDEX = 1
|
|
LDA #0
|
|
STA :NACCUM ; ACCUM = 0
|
|
STA :NACCUM+1
|
|
STA :SNGFLAG ; SIGN IS POSITIVE
|
|
*
|
|
** CHECK THAT BUFFER IS NOT ZERO
|
|
*
|
|
TXA
|
|
BNE :INIT1 ; EXIT WITH ACCUM = 0
|
|
; IF BUFFER IS EMPTY
|
|
JMP :EREXIT ; ERROR EXIT IF NOTHING
|
|
; IN BUFFER
|
|
:INIT1
|
|
LDY :NINDEX
|
|
LDA (ADDR1),Y
|
|
CMP #173
|
|
BNE :PLUS ; BR IF NOT -
|
|
LDA #$0FF
|
|
STA :SNGFLAG ; ELSE SIGN IS NEGATIVE
|
|
INC :NINDEX
|
|
DEX ; DECREMENT COUNT
|
|
BEQ :EREXIT ; ERROR EXIT IF ONLY
|
|
; - IN BUFFER
|
|
JMP :CNVERT
|
|
:PLUS
|
|
CMP #'+'
|
|
BNE :CHKDIG ; START CONVERSION IF 1ST
|
|
; CHARACTER IS NOT A +
|
|
INC :NINDEX
|
|
DEX ; DEC COUNT; IGNORE + SIGN
|
|
BEQ :EREXIT ; ERROR EXIT IF ONLY
|
|
; + IN THE BUFFER
|
|
:CNVERT
|
|
LDY :NINDEX
|
|
LDA (ADDR1),Y
|
|
; GET NEXT CHAR
|
|
:CHKDIG
|
|
CMP #$B0 ; "0"
|
|
BMI :EREXIT ; ERROR IF NOT A NUMERAL
|
|
CMP #$BA ; '9'+1; TECHNICALLY :
|
|
BPL :EREXIT ; ERR IF > 9 (NOT NUMERAL)
|
|
PHA ; PUSH DIGIT TO STACK
|
|
*
|
|
** VALID DECIMAL DIGIT SO
|
|
** ACCUM = ACCUM * 10
|
|
** = * (8+2)
|
|
** = (ACCUM * 8) + (ACCUM * 2)
|
|
*
|
|
ASL :NACCUM
|
|
ROL :NACCUM+1 ; TIMES 2
|
|
LDA :NACCUM
|
|
LDY :NACCUM+1 ; SAVE ACCUM * 2
|
|
ASL :NACCUM
|
|
ROL :NACCUM+1
|
|
ASL :NACCUM
|
|
ROL :NACCUM+1 ; TIMES 8
|
|
CLC
|
|
ADC :NACCUM ; SUM WITH * 2
|
|
STA :NACCUM
|
|
TYA
|
|
ADC :NACCUM+1
|
|
STA :NACCUM+1 ; ACCUM=ACCUM * 10
|
|
*
|
|
** ADD IN THE NEXT DIGIT
|
|
** ACCUM = ACCUM + DIGIT
|
|
*
|
|
PLA ; GET THE DIGIT NACK
|
|
SEC
|
|
SBC #$B0
|
|
CLC ; CONVERT STR TO BIN
|
|
ADC :NACCUM
|
|
STA :NACCUM
|
|
BCC :D2B1 ; BRANCH IF NO CARRY TO HBYTE
|
|
INC :NACCUM+1 ; ELSE INC HIGH BYTE
|
|
:D2B1
|
|
INC :NINDEX ;INC TO NEXT CHARACTER
|
|
DEX
|
|
BNE :CNVERT ; CONTINUE CONVERSION
|
|
LDA :SNGFLAG
|
|
BPL :OKEXIT ; BR IF VAL IS POSITIVE
|
|
LDA #0 ; ELSE REPLACE WITH -RESULT
|
|
SEC
|
|
SBC :NACCUM
|
|
STA :NACCUM
|
|
LDA #0
|
|
SBC :NACCUM+1
|
|
STA :NACCUM+1
|
|
*
|
|
** GET THE BINARY VALUE AND RETURN
|
|
*
|
|
:OKEXIT
|
|
CLC
|
|
BCC :EXIT
|
|
:EREXIT
|
|
SEC
|
|
:EXIT
|
|
*
|
|
** RESTORE RETURN ADDRESS
|
|
*
|
|
LDA RETADR+1
|
|
PHA
|
|
LDA RETADR
|
|
PHA
|
|
*
|
|
LDX :NACCUM+1
|
|
LDY :NACCUM
|
|
STY RETURN
|
|
STX RETURN+1
|
|
LDA #2
|
|
STA RETLEN
|
|
LDA :NINDEX
|
|
*
|
|
RTS
|
|
*
|
|
** DATA
|
|
*
|
|
:NACCUM DS 2
|
|
:SNGFLAG DS 1
|
|
:NINDEX DS 1
|
|
*
|
|
STRINGSX
|
|
*
|