searchstr

searchstr:
;BC points to input file
;IX points to malware code
;HL is the size of the file
;DE is the size of the malware code
;Output: nz if no match, else z. HL points to match+1

    or a
    sbc hl,de
    ret c
;swap HL and BC
    ld a,b
    ld b,h
    ld h,a
    ld a,c
    ld c,l
    ld l,a
;reformat counter DE
    dec de
    inc e
    inc d
;begin search
loop0:
    ld a,(ix)
    cpir
    ret nz
    jp po,compare
    push hl
    push de
    push ix
    call compare
    pop ix
    pop de
    pop hl
    ret z
    jp loop0
compare:
    inc ix
    ld a,(ix)
    cp (hl)
    ret nz
    inc hl
    dec e
    jp nz,compare
    dec d
    jr nz,compare
    ret