Added strppd(), refactored local labels in string.a02

This commit is contained in:
Curtis F Kaylor 2021-09-04 18:37:17 -04:00
parent e8777b6077
commit a7864da8f9
1 changed files with 110 additions and 88 deletions

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@ -1,46 +1,73 @@
; 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
; external zero page byte pairs SRCPTR and DSTPTR
; and external bytes TEMP0 and TEMP1
SUBROUTINE STRING
;strapd(c, s) - Append charecter c to string s
;Args: A = Character to be appended
; X,Y = Pointer to string
;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
BMI .RETFLS ;Return 255 if > 127
LDA TEMP0 ;Restore Character to Append
STRAPL: STA (SRCLO),Y ;Store at End of String
BEQ STRLEX ;Exit if NUL
.APDLOP STA (SRCPTR),Y ;Store at End of String
BEQ .LENEND ;Exit if NUL
INY ;Increment Past New Character
LDA #0 ;Set Character to NUL
BEQ STRAPL ;and Append to String
BEQ .APDLOP ;and Append to String
;strppd(c, s) - Prepend Charecter to String
;Args: A = Character to be appended
; X,Y = Pointer to string
;Sets: N,Z
;Returns A = Insterted Character
STRPPD: STA TEMP0 ;Save Character to Append
JSR STRLEN ;Get Length of String
BMI .RETFLS ;Return 255 if > 127
INY ;Bump up string length
TYA ;Push string length onto stack
PHA
.PPDLOP DEY ;Copy Preceding Chacter
LDA (SRCPTR),Y
INY ;into Currebt Position
STA (SRCPTR),Y
DEY ;Move to Preceding Position
BNE .PPDLOP ;and Loop
LDA TEMP0 ;Retrieve Character
STA (SRCPTR),Y ;and Store in Position 0
PLA ;Retrieve new string length
BEQ .RETORA ;Set Flags and Return`
;strcmp(&s) - Compare String (to Destination String)
;Requires: DSTLO, DSTHI - Pointer to destination string
;Requires: DSTPTR - Pointer to destination string
;Args: X,Y = Pointer to source string
;Sets: SRCLO,SRCHI = Pointer to string
;Sets: SRCPTR = 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
.CMPLOP LDA (DSTPTR),Y ;Load Destination Character
CMP (SRCPTR),Y ;Compare Against Source Character
BNE .CMPEND ;If Equal
ORA (SRCPTR),Y ; OR with Source Character
BEQ .RETURN ; 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
BPL .CMPLOP ; and Loop if < 128
.CMPEND BCC .RETFLS ;If Source < Destination, Return $FF & Carry Clear
LDA #$01 ;Else Return 1 and Carry Set
STRCMR: RTS ;
.RETURN 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
;Sets: SRCPTR = Pointer to string
; TEMP3 = Character being searched for
;Affects: N,Z
;Returns: A = Position in string, C=1 if found
@ -48,106 +75,99 @@ STRCMR: RTS ;
; 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
.CHRLOP LDA (SRCPTR),Y ;Get Next Character
BEQ .CLCFLS ;If NUL, Return $FF and Carry Clear
CMP TEMP3 ;Compare Character
BEQ STRLEX ;If Found, Return Index
BEQ .LENEND ;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
BPL .CHRLOP ;Else Return $FF and Carry Clear
.CLCFLS CLC ;Clear Carry
.RETFLS LDA #$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
;Sets: SRCPTR, SRCPTR+1 - Pointer to String
;strlen(&s) - Return Length of String
;Args: X,Y - Pointer to string
;Sets: SRCLO,SRCHI = Pointer to source string
;Sets: SRCPTR = 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
.LENLOP LDA (SRCPTR),Y ;Get Next Character
BEQ .LENEND ;If <> NUL
INY ; Increment Index
BPL STRLEL ; and Loop if < 128
STRLEX: TYA ;Transfer Index to Accumulator
ORA #0 ;Set N and Z flags
BPL .LENLOP ; and Loop if < 128
.LENEND TYA ;Transfer Index to Accumulator
.RETORA 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
;strcpb(&s) - Copy String to System Buffer
STRCPB: JSR SETSRC ;Set Source Pointer to String Address
JSR SETDSB ;Set Destination Pointer to System Buffer
BVC STRCPA ;Execute String Copy
;strcat(&s) Concatenate String (to Destination String)
;Requires: DSTLO, DSTHI - Pointer to destination string
;Requires: DSTPTR - Pointer to destination string
;Args: X,Y = Pointer to source string
;Sets: SRCLO,SRCHI = Pointer to source string
;Sets: SRCPTR = 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 ;
.CATLOP LDA (DSTPTR),Y ;Find end of Destination String
BEQ .CATEND ;
INY ;
BPL STRCAL ;
STRCAX: STY TEMP3 ;Subtract Destination String Length
LDA SRCLO ; from Source String Pointer
BPL .CATLOP ;
.CATEND STY TEMP3 ;Subtract Destination String Length
LDA SRCPTR ; from Source String Pointer
SEC
SBC TEMP3
STA SRCLO
LDA SRCHI
STA SRCPTR
LDA SRCPTR+1
SBC #$00
STA SRCHI
JMP STRCPL ;Execute String Copy
STA SRCPTR+1
JMP .CPYLOP ;Execute String Copy
;strcpy(&s) - Copy String (to Destination String)
;Requires: DSTLO, DSTHI - Pointer to destination string
;Requires: DSTPTR - Pointer to destination string
;Args: X,Y = Pointer to source string
;Sets: SRCLO,SRCHI = Pointer to source string
;Sets: SRCPTR = 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
BEQ .CPYLOP ;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
.CPYLOP LDA (SRCPTR),Y ;Get Character from Source String
STA (DSTPTR),Y ;Copy to Destination String
BEQ .CPYEND ;If <> NUL
INY ; Increment Index
BPL STRCPL ; and Loop if < 128
STRCPX: TYA ;Transfer Index to Accumulator
BPL .CPYLOP ; and Loop if < 128
.CPYEND 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
;Requires: DSTPTR - 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
;Sets: SRCPTR = 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
ADC SRCPTR ;Move Source Pointer
STA SRCPTR ; to Specified Position in String
BCC .CPYLOP
INC SRCPTR+1
JMP .CPYLOP ;and Jump Into String Copy Loop
;strstr(&s) - Search for String (in Destination String)
;Requires: DSTLO, DSTHI - Pointer to destination string
;Requires: DSTPTR - Pointer to destination string
;Args: X,Y = Pointer to search string
;Sets: DSTLO,DSTHI = Pointer to position in source string
;Sets: DSTPTR = Pointer to position in source string
; End of string if not found
; SRCLO,SRCHI = Pointer to source string
; SRCPTR = Pointer to source string
; TEMP3 = Last position checked in destination string
;Affects: N,Z
;Returns: A = Position, C=1 if found
@ -155,29 +175,29 @@ STRCUT: JSR SETSRC ;Initialize Source String
; 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
.STRLOP LDY #$00; ;Initialize Compare Offset
LDA (DSTPTR),Y ;Get Start Character in Destination
BEQ .CLCFLS ;If NUL return $FF and Carry Clear
JSR .CMPLOP ;Jump into Compare Loop
BEQ .STREND ;If Not Equal
BMI .STRNXT ; If Source is Greater
LDA (SRCPTR),Y ; If at End of Source String
BEQ .STREND ; Return Current Position
.STRNXT INC TEMP3 ; Else Increment Position
BMI .CLCFLS ; If > 127 return $FF and Carry Clear
INC DSTPTR ; Increment Source Pointer
BNE .STRLOP
INC DSTPTR+1 ; If not End of Memory
BNE .STRLOP ; Loop
BEQ .CLCFLS ; Else return $FF and Carry Clear
.STREND SEC ;Else Set Carry
LDA TEMP3 ; Load Position
RTS ; and Return
;strrch(c, &s) - Find Last Occurance Character in String
;Args: A = Character to look for
; X,Y = Pointer to string to search in
;Sets: SRCLO,SRCHI = Pointer to string
;Sets: SRCPTR = Pointer to string
; TEMP3 = Character being searched for
;Affects: Y,C,N,Z
;Returns: A,X = Position of last occurance in string
@ -186,14 +206,16 @@ STRSTX: SEC ;Else Set Carry
STRRCH: JSR SETSRC ;Initialize Source String
STA TEMP3; ;Save Search Character (alternate entry point)
LDX #$FF ;Initialize Position
STRRCL: LDA (SRCLO),Y ;Get Next Character
BEQ STRRCX ;If NUL, Exit with Position
.RCHLOP LDA (SRCPTR),Y ;Get Next Character
BEQ .RCHEND ;If NUL, Exit with Position
CMP TEMP3 ;Compare Character
BNE STRRCS ;If Found
BNE .RCHNXT ;If Found
TYA ; Store Counter
TAX
STRRCS: INY ;Increment Counter
BPL STRRCL ; and Loop if < 128
STRRCX: TXA ;Copy Position to Accumulater
.RCHNXT INY ;Increment Counter
BPL .RCHLOP ; and Loop if < 128
.RCHEND TXA ;Copy Position to Accumulater
RTS ; and Return
ENDSUBROUTINE