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C02/include/stringx.a02
2018-01-28 13:30:49 -05:00

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