mirror of
https://github.com/irmen/prog8.git
synced 2024-12-26 14:29:35 +00:00
387 lines
11 KiB
Lua
387 lines
11 KiB
Lua
; 0-terminated string manipulation routines.
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string {
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%option no_symbol_prefixing
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asmsub length(uword string @AY) clobbers(A) -> ubyte @Y {
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; Returns the number of bytes in the string.
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; This value is determined during runtime and counts upto the first terminating 0 byte in the string,
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; regardless of the size of the string during compilation time. Don’t confuse this with len and sizeof!
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%asm {{
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sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
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ldy #0
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- lda (P8ZP_SCRATCH_W1),y
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beq +
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iny
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bne -
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+ rts
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}}
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}
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asmsub left(uword source @R0, ubyte length @A, uword target @R1) clobbers(A, Y) {
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; Copies the left side of the source string of the given length to target string.
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; It is assumed the target string buffer is large enough to contain the result.
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; Also, you have to make sure yourself that length is smaller or equal to the length of the source string.
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; Modifies in-place, doesn’t return a value (so can’t be used in an expression).
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%asm {{
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; need to copy the the cx16 virtual registers to zeropage to be compatible with C64...
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ldy cx16.r0
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sty P8ZP_SCRATCH_W1
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ldy cx16.r0+1
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sty P8ZP_SCRATCH_W1+1
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ldy cx16.r1
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sty P8ZP_SCRATCH_W2
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ldy cx16.r1+1
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sty P8ZP_SCRATCH_W2+1
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tay
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lda #0
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sta (P8ZP_SCRATCH_W2),y
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cpy #0
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bne _loop
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rts
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_loop dey
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lda (P8ZP_SCRATCH_W1),y
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sta (P8ZP_SCRATCH_W2),y
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cpy #0
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bne _loop
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+ rts
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}}
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; asmgen.out(" jsr prog8_lib.func_leftstr")
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}
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asmsub right(uword source @R0, ubyte length @A, uword target @R1) clobbers(A,Y) {
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; Copies the right side of the source string of the given length to target string.
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; It is assumed the target string buffer is large enough to contain the result.
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; Also, you have to make sure yourself that length is smaller or equal to the length of the source string.
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; Modifies in-place, doesn’t return a value (so can’t be used in an expression).
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%asm {{
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; need to copy the the cx16 virtual registers to zeropage to be compatible with C64...
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sta P8ZP_SCRATCH_B1
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lda cx16.r0
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ldy cx16.r0+1
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jsr string.length
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tya
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sec
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sbc P8ZP_SCRATCH_B1
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clc
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adc cx16.r0
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sta P8ZP_SCRATCH_W1
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lda cx16.r0+1
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adc #0
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sta P8ZP_SCRATCH_W1+1
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ldy cx16.r1
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sty P8ZP_SCRATCH_W2
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ldy cx16.r1+1
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sty P8ZP_SCRATCH_W2+1
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ldy P8ZP_SCRATCH_B1
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lda #0
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sta (P8ZP_SCRATCH_W2),y
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cpy #0
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bne _loop
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rts
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_loop dey
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lda (P8ZP_SCRATCH_W1),y
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sta (P8ZP_SCRATCH_W2),y
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cpy #0
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bne _loop
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+ rts
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}}
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}
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asmsub slice(uword source @R0, ubyte start @A, ubyte length @Y, uword target @R1) clobbers(A, Y) {
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; Copies a segment from the source string, starting at the given index,
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; and of the given length to target string.
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; It is assumed the target string buffer is large enough to contain the result.
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; Also, you have to make sure yourself that start and length are within bounds of the strings.
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; Modifies in-place, doesn’t return a value (so can’t be used in an expression).
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%asm {{
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; need to copy the the cx16 virtual registers to zeropage to be compatible with C64...
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; substr(source, target, start, length)
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sta P8ZP_SCRATCH_B1
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lda cx16.r0
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sta P8ZP_SCRATCH_W1
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lda cx16.r0+1
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sta P8ZP_SCRATCH_W1+1
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lda cx16.r1
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sta P8ZP_SCRATCH_W2
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lda cx16.r1+1
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sta P8ZP_SCRATCH_W2+1
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; adjust src location
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clc
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lda P8ZP_SCRATCH_W1
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adc P8ZP_SCRATCH_B1
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sta P8ZP_SCRATCH_W1
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bcc +
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inc P8ZP_SCRATCH_W1+1
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+ lda #0
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sta (P8ZP_SCRATCH_W2),y
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beq _startloop
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- lda (P8ZP_SCRATCH_W1),y
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sta (P8ZP_SCRATCH_W2),y
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_startloop dey
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cpy #$ff
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bne -
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rts
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}}
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}
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asmsub find(uword string @R0, ubyte character @A) -> ubyte @A, bool @Pc {
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; Locates the first position of the given character in the string,
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; returns Carry set if found + index in A, or A=0 + Carry clear if not found.
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%asm {{
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; need to copy the the cx16 virtual registers to zeropage to make this run on C64...
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sta P8ZP_SCRATCH_B1
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lda cx16.r0
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ldy cx16.r0+1
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sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
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ldy #0
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- lda (P8ZP_SCRATCH_W1),y
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beq _notfound
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cmp P8ZP_SCRATCH_B1
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beq _found
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iny
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bne -
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_notfound lda #0
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clc
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rts
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_found tya
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sec
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rts
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}}
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}
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asmsub copy(uword source @R0, uword target @AY) clobbers(A) -> ubyte @Y {
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; Copy a string to another, overwriting that one.
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; Returns the length of the string that was copied.
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; Often you don’t have to call this explicitly and can just write string1 = string2
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; but this function is useful if you’re dealing with addresses for instance.
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%asm {{
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sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
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lda cx16.r0
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ldy cx16.r0+1
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jmp prog8_lib.strcpy
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}}
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}
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asmsub append(uword target @R0, uword suffix @R1) clobbers(Y) -> ubyte @A {
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; Append the suffix string to the target. (make sure the buffer is large enough!)
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; Returns the length of the resulting string.
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%asm {{
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lda cx16.r0
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ldy cx16.r0+1
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jsr length
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sty P8ZP_SCRATCH_B1
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tya
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clc
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adc cx16.r0
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sta P8ZP_SCRATCH_W1
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lda cx16.r0+1
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adc #0
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sta P8ZP_SCRATCH_W1+1
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lda cx16.r1
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ldy cx16.r1+1
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jsr prog8_lib.strcpy
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tya
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clc
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adc P8ZP_SCRATCH_B1
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rts
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}}
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}
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asmsub compare(uword string1 @R0, uword string2 @AY) clobbers(Y) -> byte @A {
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; Compares two strings for sorting.
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; Returns -1 (255), 0 or 1 depending on wether string1 sorts before, equal or after string2.
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; Note that you can also directly compare strings and string values with eachother using
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; comparison operators ==, < etcetera (it will use strcmp for you under water automatically).
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%asm {{
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sta P8ZP_SCRATCH_W2
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sty P8ZP_SCRATCH_W2+1
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lda cx16.r0
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ldy cx16.r0+1
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jmp prog8_lib.strcmp_mem
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}}
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}
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asmsub lower(uword st @AY) -> ubyte @Y {
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; Lowercases the petscii string in-place. Returns length of the string.
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; (for efficiency, non-letter characters > 128 will also not be left intact,
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; but regular text doesn't usually contain those characters anyway.)
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%asm {{
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sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
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ldy #0
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- lda (P8ZP_SCRATCH_W1),y
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beq _done
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and #$7f
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cmp #97
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bcc +
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cmp #123
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bcs +
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and #%11011111
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+ sta (P8ZP_SCRATCH_W1),y
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iny
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bne -
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_done rts
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}}
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}
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asmsub upper(uword st @AY) -> ubyte @Y {
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; Uppercases the petscii string in-place. Returns length of the string.
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%asm {{
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sta P8ZP_SCRATCH_W1
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sty P8ZP_SCRATCH_W1+1
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ldy #0
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- lda (P8ZP_SCRATCH_W1),y
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beq _done
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cmp #65
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bcc +
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cmp #91
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bcs +
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ora #%00100000
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+ sta (P8ZP_SCRATCH_W1),y
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iny
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bne -
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_done rts
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}}
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}
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asmsub lowerchar(ubyte character @A) -> ubyte @A {
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%asm {{
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and #$7f
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cmp #97
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bcc +
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cmp #123
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bcs +
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and #%11011111
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+ rts
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}}
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}
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asmsub upperchar(ubyte character @A) -> ubyte @A {
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%asm {{
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cmp #65
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bcc +
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cmp #91
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bcs +
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ora #%00100000
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+ rts
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}}
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}
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sub startswith(str st, str prefix) -> bool {
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ubyte prefix_len = length(prefix)
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ubyte str_len = length(st)
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if prefix_len > str_len
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return false
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cx16.r9L = st[prefix_len]
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st[prefix_len] = 0
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cx16.r9H = compare(st, prefix) as ubyte
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st[prefix_len] = cx16.r9L
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return cx16.r9H==0
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}
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sub endswith(str st, str suffix) -> bool {
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ubyte suffix_len = length(suffix)
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ubyte str_len = length(st)
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if suffix_len > str_len
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return false
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return compare(st + str_len - suffix_len, suffix) == 0
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}
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asmsub pattern_match(str string @AY, str pattern @R0) clobbers(Y) -> ubyte @A {
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%asm {{
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; pattern matching of a string.
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; Input: cx16.r0: A NUL-terminated, <255-length pattern
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; AY: A NUL-terminated, <255-length string
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;
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; Output: A = 1 if the string matches the pattern, A = 0 if not.
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;
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; Notes: Clobbers A, X, Y. Each * in the pattern uses 4 bytes of stack.
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;
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; see http://6502.org/source/strings/patmatch.htm
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strptr = P8ZP_SCRATCH_W1
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sta strptr
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sty strptr+1
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lda cx16.r0
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sta modify_pattern1+1
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sta modify_pattern2+1
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lda cx16.r0+1
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sta modify_pattern1+2
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sta modify_pattern2+2
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jsr _match
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lda #0
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rol a
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rts
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_match
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ldx #$00 ; x is an index in the pattern
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ldy #$ff ; y is an index in the string
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modify_pattern1
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next lda $ffff,x ; look at next pattern character MODIFIED
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cmp #'*' ; is it a star?
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beq star ; yes, do the complicated stuff
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iny ; no, let's look at the string
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cmp #'?' ; is the pattern caracter a ques?
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bne reg ; no, it's a regular character
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lda (strptr),y ; yes, so it will match anything
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beq fail ; except the end of string
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reg cmp (strptr),y ; are both characters the same?
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bne fail ; no, so no match
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inx ; yes, keep checking
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cmp #0 ; are we at end of string?
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bne next ; not yet, loop
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found rts ; success, return with c=1
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star inx ; skip star in pattern
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modify_pattern2
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cmp $ffff,x ; string of stars equals one star MODIFIED
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beq star ; so skip them also
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stloop txa ; we first try to match with * = ""
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pha ; and grow it by 1 character every
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tya ; time we loop
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pha ; save x and y on stack
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jsr next ; recursive call
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pla ; restore x and y
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tay
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pla
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tax
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bcs found ; we found a match, return with c=1
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iny ; no match yet, try to grow * string
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lda (strptr),y ; are we at the end of string?
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bne stloop ; not yet, add a character
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fail clc ; yes, no match found, return with c=0
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rts
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}}
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}
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asmsub hash(str string @R0) -> ubyte @A {
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; experimental 8 bit hashing function.
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; hash(-1)=179; clear carry; hash(i) = ROL hash(i-1) XOR string[i]
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; On the English word list in /usr/share/dict/words it seems to have a pretty even distribution
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%asm {{
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lda #179
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sta P8ZP_SCRATCH_REG
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ldy #0
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clc
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- lda (cx16.r0),y
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beq +
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rol P8ZP_SCRATCH_REG
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eor P8ZP_SCRATCH_REG
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sta P8ZP_SCRATCH_REG
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iny
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bne -
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+ lda P8ZP_SCRATCH_REG
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rts
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}}
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}
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}
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