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85 lines
2.9 KiB
Lua
85 lines
2.9 KiB
Lua
; Internal library routines - always included by the compiler
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;
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; Written by Irmen de Jong (irmen@razorvine.net) - license: GNU GPL 3.0
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prog8_lib {
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%asminclude "library:prog8_lib.asm"
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%asminclude "library:prog8_funcs.asm"
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uword @zp retval_interm_uw ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)
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word @zp retval_interm_w ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)
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ubyte @zp retval_interm_ub ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)
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byte @zp retval_interm_b ; to store intermediary expression results for return values (hopefully allocated on ZP to reduce code size)
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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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str = P8ZP_SCRATCH_W1
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stx P8ZP_SCRATCH_REG
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sta str
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sty str+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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adc #0
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ldx P8ZP_SCRATCH_REG
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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 (str),y ; yes, so it will match anything
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beq fail ; except the end of string
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reg cmp (str),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 (str),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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}
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