cscg22-gearboy

CSCG 2022 Challenge 'Gearboy'
git clone https://git.sinitax.com/sinitax/cscg22-gearboy
Log | Files | Refs | sfeed.txt

_strcmp.s (839B)

      1        .module strcmp
      2
      3        .area   _HOME
      4
      5; int strcmp(const char *s1, const char *s2) 
      6_strcmp::
      7        lda     hl,2(sp)
      8        ld      a,(hl+)
      9        ld      e, a
     10        ld      a,(hl+)
     11        ld      d, a
     12        ld      a,(hl+)
     13        ld      h,(hl)
     14        ld      l,a
     151$:     
     16        ld      a,(de)
     17        sub     (hl)            ; s1[i]==s2[i]?
     18        jr      nz, 2$          ; -> Different
     19        ;; A == 0
     20        cp      (hl)            ; s1[i]==s2[i]==0?
     21        
     22        inc     de
     23        inc     hl
     24        jr      nz, 1$          ; ^ Didn't reach a null character. Loop.
     25        
     26        ; Yes. return 0;
     27        ld      d, a            ; Since a == 0 this is faster than a 16 bit immediate load.
     28        ld      e, a
     29        ret
     302$:
     31        ld      de,#-1
     32        ret     c
     33
     34        ld      de,#1
     35        ret