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76 lines
3.0 KiB
Plaintext
76 lines
3.0 KiB
Plaintext
; C02 library stringx.h02 assembly language subroutines
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; Requires the subroutines and definitions from string.asm
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;Common Code - Initialize Variables
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STRXSI: JSR SETSRC ;Initialize Source String
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STY TEMP1 ;Save Destination Pointer
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LDX #0 ;Set End of String Flag
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RTS ; and Return
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;Common Code - Check Next Character in Destination String
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STRXSL: LDY TEMP1
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LDA (DSTLO),Y ;Get Next Character in Destination String
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BEQ STRXST ;If NUL, Return from Calling Routine
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LDY #0 ;Initialize Source Pointer
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JMP STRCHA ;Search for Character in Source and Return
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;Common Code - Exit with Result
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STRXST: PLA ;Pop Return Address Off Stack
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PLA ; to force exit from Calling Routine
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STRXSX: TXA ;Load End of String Flag into Accumulator
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BNE STRXSR ;If 0 Then
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STRXSP: LDA TEMP1 ; Load Character Position into Accumulator
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STRXSR: RTS ;Return
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;strpbk(&s) - Return position of first character in Destination
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; also contained in Source
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;Requires: DSTLO, dsthi - Pointer to destination string
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;Args: X,Y = Pointer to source string
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;Sets: srclo,srchi = Pointer to source string
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; TEMP1 = Position of last character checked
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;Uses: TEMP0
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;Affects: C,X,Y
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;Returns: A = Position of first character that matches
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; $FF if no characters matched
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STRPBK: JSR STRXSI ;Initialize Variables
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DEX ;Change End of String Flag to $FF
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BNE STRBRL ;Jump into strbrk subroutine
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;strbrk(&s) - Return length of Destination with characters
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; not contained in Source
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;Requires: DSTLO, dsthi - Pointer to destination string
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;Args: X,Y = Pointer to source string
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;Sets: srclo,srchi = Pointer to source string
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; TEMP1 = Return value
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;Uses: TEMP0
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;Affects: C,X,Y
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;Returns: A = Length of matching string segment
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; Z = 1 if no characters matched
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; N = 1 if > 127 characters matched
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STRCSP: ;Alias to strbrk
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STRBRK: JSR STRXSI ;Initialize Variables
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STRBRL: JSR STRXSL ;and Search for Character in Source String
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BCS STRXSP ;If Not Found
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INC TEMP1 ; Increment Destination Pointer
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BPL STRBRL ; and Loop if < 128
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BMI STRXSX ;and Return Not Found
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;strspn(&s) - Return length of Destination with characters
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; contained in Source
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;Requires: DSTLO, dsthi - Pointer to destination string
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;Args: X,Y = Pointer to source string
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;Sets: srclo,srchi = Pointer to source string
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; TEMP1 = Return value
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;Uses: TEMP0
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;Affects: C,X,Y
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;Returns: A = Length of matching string segment
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; Z = 1 if no characters matched
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; N = 1 if > 127 characters matched
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STRSPN: JSR STRXSI ;Initialize Variables
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STRSPL: JSR STRXSL ;and Search for Character in Source String
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BCC STRXSP ;If Found
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INC TEMP1 ; Increment Destination Pointer
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BPL STRSPL ; and Loop if < 128
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BMI STRXSP ;Else Return Position
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