Grammer2/src/cmd/searchstring.z80

;SearchString is used by inString  and Lbl




searchstring_routine:
;Inputs:
;     HL points to the string to search
;     BC size of the string to search
;     DE points to string to find
;     IX is the size of the string to find
;Outputs:
;     c flag set if there was a match, nc if no match was found
;     HL points to the match if there was one
;     DE is preserved
;Destroys:
;     A,BC

;First, we'll do BC-IX -> BC, and make sure it isn't negative

  push hl

  ld h,b
  ld l,c
  push ix
  pop bc
  dec bc
;Save the size of the string to find
  ld (TempWord1),bc
  or a
  sbc hl,bc
  ld b,h
  ld c,l
  pop hl

  ret z
  ccf
  ret nc  ;This means the input was smaller than the string to search for!


  jr searchstring_begin
searchstring_match:
  dec hl
  scf
  ret

_:
;at this point, we have a match
;now we need to compare the strings
  push hl
  push de
  push bc
  call +_
  pop bc
  pop de
  pop hl
  jr z,searchstring_match  ;we found our match!
  ld a,b
  or c
  jr z,searchstring_nomatch+1
searchstring_begin:
  ld a,(de)
  cpir
  jr z,-_
searchstring_nomatch:
  xor a
  ld h,a
  ld l,a
  ret

_:
  ld bc,(TempWord1)
_:
  inc de
  ld a,(de)
  cpi
  ret nz
  jp pe,-_
  ret