mirror of
https://github.com/RevCurtisP/C02.git
synced 2024-11-22 01:31:33 +00:00
195 lines
7.8 KiB
Plaintext
195 lines
7.8 KiB
Plaintext
; C02 library string.h02 assembly language subroutines
|
|
; Requires external routines SETSRC and SETDST
|
|
; Requires the following RAM locations be defined
|
|
; external zero page byte pairs SRCLO,SRCHI and DSTLO,DSTHI
|
|
; and external bytes TEMP0 and TEMP1
|
|
|
|
;Affects N,Z
|
|
;Returns A,Y = New String Length
|
|
STRAPD: STA TEMP0 ;Save Character to Append
|
|
JSR STRLEN ;Get Length of String
|
|
BMI STRCLX ;Return 255 if > 127
|
|
LDA TEMP0 ;Restore Character to Append
|
|
STRAPL: STA (SRCLO),Y ;Store at End of String
|
|
BEQ STRLEX ;Exit if NUL
|
|
INY ;Increment Past New Character
|
|
LDA #0 ;Set Character to NUL
|
|
BEQ STRAPL ;and Append to String
|
|
|
|
;strcmp(&s) - Compare String (to Destination String)
|
|
;Requires: DSTLO, DSTHI - Pointer to destination string
|
|
;Args: X,Y = Pointer to source string
|
|
;Sets: SRCLO,SRCHI = Pointer to string
|
|
;Affects N,Z
|
|
;Returns A=$01 and C=1 if Destination > Source
|
|
; A=$00 and Z=1, C=1 if Destination = Source
|
|
; A=$FF and C=0 if Destination < Source
|
|
; Y=Position of first character that differs
|
|
STRCMP: JSR SETSRC ;Initialize Source String
|
|
STRCML: LDA (DSTLO),Y ;Load Destination Character
|
|
CMP (SRCLO),Y ;Compare Against Source Character
|
|
BNE STRCMX ;If Equal
|
|
ORA (SRCLO),Y ; OR with Source Character
|
|
BEQ STRCMR ; If Both are 0, Return 0
|
|
INY ; Increment Offset
|
|
BPL STRCML ; and Loop if < 128
|
|
STRCMX: BCC STRCLX ;If Source < Destination, Return $FF & Carry Clear
|
|
LDA #$01 ;Else Return 1 and Carry Set
|
|
STRCMR: RTS ;
|
|
|
|
;strchr(c, &s) - Find First Occurance of Character in String
|
|
;Args: A = Character to look for
|
|
; X,Y = Pointer to string to search in
|
|
;Sets: SRCLO,SRCHI = Pointer to string
|
|
; TEMP3 = Character being searched for
|
|
;Affects: N,Z
|
|
;Returns: A = Position in string, C=1 if found
|
|
; A = $FF, C=0 if not found
|
|
; Y = Position of last character scanned
|
|
STRCHR: JSR SETSRC ;Initialize Source String
|
|
STRCHA: STA TEMP3; ;Save Search Character (alternate entry point)
|
|
STRCHL: LDA (SRCLO),Y ;Get Next Character
|
|
BEQ STRCLC ;If NUL, Return $FF and Carry Clear
|
|
CMP TEMP3 ;Compare Character
|
|
BEQ STRLEX ;If Found, Return Index
|
|
INY ;Increment Counter and Loop if < 128
|
|
BPL STRCHL ;Else Return $FF and Carry Clear
|
|
STRCLC: CLC ;Clear Carry
|
|
STRCLX: LDA #$FF ;Load -1 into Accumulater
|
|
RTS ;and Return
|
|
|
|
;strapd(c, &s) - Append Character to String
|
|
;Args: A = Character to Append
|
|
; X,Y = Pointer to String
|
|
;Sets: SRCLO, SRCHI - Pointer to String
|
|
;strlen(&s) - Return Length of String
|
|
;Args: X,Y - Pointer to string
|
|
;Sets: SRCLO,SRCHI = Pointer to source string
|
|
;Returns: A,Y = Length of string
|
|
; N,Z based on A
|
|
STRLEN: JSR SETSRC ;Initialize Source String
|
|
STRLEL: LDA (SRCLO),Y ;Get Next Character
|
|
BEQ STRLEX ;If <> NUL
|
|
INY ; Increment Index
|
|
BPL STRLEL ; and Loop if < 128
|
|
STRLEX: TYA ;Transfer Index to Accumulator
|
|
ORA #0 ;Set N and Z flags
|
|
RTS ;and Return
|
|
|
|
;strdst(&s) - Set Destination String
|
|
; Called before strcat(), strcmp(), strcpy(), strstr()
|
|
;Args: X,Y = Pointer to destination string
|
|
;Sets: SRCLO,SRCHI = Pointer to destination string
|
|
;Affects: N,Z
|
|
STRDST EQU SETDST ;Aliased to System Header function
|
|
|
|
;strcat(&s) Concatenate String (to Destination String)
|
|
;Requires: DSTLO, DSTHI - Pointer to destination string
|
|
;Args: X,Y = Pointer to source string
|
|
;Sets: SRCLO,SRCHI = Pointer to source string
|
|
; TEMP3 = Length of source prior to concatenation
|
|
;Affects: C,N,Z
|
|
;Returns: A,Y = Total length of concatenated string
|
|
STRCAT: JSR SETSRC ;Initialize Source String
|
|
STRCAL: LDA (DSTLO),Y ;Find end of Destination String
|
|
BEQ STRCAX ;
|
|
INY ;
|
|
BPL STRCAL ;
|
|
STRCAX: STY TEMP3 ;Subtract Destination String Length
|
|
LDA SRCLO ; from Source String Pointer
|
|
SEC
|
|
SBC TEMP3
|
|
STA SRCLO
|
|
LDA SRCHI
|
|
SBC #$00
|
|
STA SRCHI
|
|
JMP STRCPL ;Execute String Copy
|
|
|
|
;strcpy(&s) - Copy String (to Destination String)
|
|
;Requires: DSTLO, DSTHI - Pointer to destination string
|
|
;Args: X,Y = Pointer to source string
|
|
;Sets: SRCLO,SRCHI = Pointer to source string
|
|
;Affects: N,Z
|
|
;Returns: A,Y = Number of characters copied
|
|
STRCPA: LDY #0 ;Alternate entry point
|
|
BEQ STRCPL ;for when Source already set
|
|
STRCPY: JSR SETSRC ;Initialize Source String
|
|
STRCPL: LDA (SRCLO),Y ;Get Character from Source String
|
|
STA (DSTLO),Y ;Copy to Destination String
|
|
BEQ STRCPX ;If <> NUL
|
|
INY ; Increment Index
|
|
BPL STRCPL ; and Loop if < 128
|
|
STRCPX: TYA ;Transfer Index to Accumulator
|
|
RTS ;and Return
|
|
|
|
;strcut(n, &s) - Copy from Position n to End of Source (into Destination)
|
|
;Requires: DSTLO, DSTHI - Pointer to destination string
|
|
;Args: A = Starting position in start string
|
|
; X,Y = Pointer to source string
|
|
;Sets: SRCLO,SRCHI = Pointer to specified position in source string
|
|
;Affects: N,Z
|
|
;Returns: A,Y = Length of copied string
|
|
STRCUT: JSR SETSRC ;Initialize Source String
|
|
CLC
|
|
ADC SRCLO ;Move Source Pointer
|
|
STA SRCLO ; to Specified Position in String
|
|
BCC STRCPL
|
|
INC SRCHI
|
|
JMP STRCPL ;and Jump Into String Copy Loop
|
|
|
|
;strstr(&s) - Search for String (in Destination String)
|
|
;Requires: DSTLO, DSTHI - Pointer to destination string
|
|
;Args: X,Y = Pointer to search string
|
|
;Sets: DSTLO,DSTHI = Pointer to position in source string
|
|
; End of string if not found
|
|
; SRCLO,SRCHI = Pointer to source string
|
|
; TEMP3 = Last position checked in destination string
|
|
;Affects: N,Z
|
|
;Returns: A = Position, C=1 if found
|
|
; A = $FF, C=0 if not found
|
|
; Y = Last position checked in source string
|
|
STRSTR: JSR SETSRC ;Initialize Source String
|
|
STY TEMP3 ;Initialize Position
|
|
STRSTL: LDY #$00; ;Initialize Compare Offset
|
|
LDA (DSTLO),Y ;Get Start Character in Destination
|
|
BEQ STRCLC ;If NUL return $FF and Carry Clear
|
|
JSR STRCML ;Jump into Compare Loop
|
|
BEQ STRSTX ;If Not Equal
|
|
BMI STRSTN ; If Source is Greater
|
|
LDA (SRCLO),Y ; If at End of Source String
|
|
BEQ STRSTX ; Return Current Position
|
|
STRSTN: INC TEMP3 ; Else Increment Position
|
|
BMI STRCLC ; If > 127 return $FF and Carry Clear
|
|
INC DSTLO ; Increment Source Pointer
|
|
BNE STRSTL
|
|
INC DSTHI ; If not End of Memory
|
|
BNE STRSTL ; Loop
|
|
BEQ STRCLC ; Else return $FF and Carry Clear
|
|
STRSTX: SEC ;Else Set Carry
|
|
LDA TEMP3 ; Load Position
|
|
RTS ; and Return
|
|
|
|
;strrch(c, &s) - Find Last Occurance Character in String
|
|
;Args: A = Character to look for
|
|
; X,Y = Pointer to string to search in
|
|
;Sets: SRCLO,SRCHI = Pointer to string
|
|
; TEMP3 = Character being searched for
|
|
;Affects: Y,C,N,Z
|
|
;Returns: A,X = Position of last occurance in string
|
|
; $FF if not found
|
|
; Y = Length of String
|
|
STRRCH: JSR SETSRC ;Initialize Source String
|
|
STA TEMP3; ;Save Search Character (alternate entry point)
|
|
LDX #$FF ;Initialize Position
|
|
STRRCL: LDA (SRCLO),Y ;Get Next Character
|
|
BEQ STRRCX ;If NUL, Exit with Position
|
|
CMP TEMP3 ;Compare Character
|
|
BNE STRRCS ;If Found
|
|
TYA ; Store Counter
|
|
TAX
|
|
STRRCS: INY ;Increment Counter
|
|
BPL STRRCL ; and Loop if < 128
|
|
STRRCX: TXA ;Copy Position to Accumulater
|
|
RTS ; and Return
|
|
|