cscg22-gearboy

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

set_tile_submap.s (3502B)

      1        .include        "global.s"
      2
      3        .title  "Set tile submap"
      4        .module SetTileSubmap
      5
      6        .area   _DATA
      7
      8.image_tile_width::
      9        .ds     0x01
     10
     11        .area   _INITIALIZED
     12
     13__submap_tile_offset::
     14        .ds     0x01
     15
     16        .area   _INITIALIZER
     17
     18        .db     0x00
     19
     20        .area   _HOME
     21
     22_set_bkg_submap::
     23        ldhl    sp, #2
     24        ld      a, (hl+)        ; b = x
     25        ld      b, a
     26        ld      c, (hl)         ; c = y
     27        
     28        ldhl    sp, #8
     29        ld      a, (hl)
     30        ldhl    sp, #4
     31        sub     (hl)
     32        ld      (.image_tile_width), a ; .image_tile_width contains corrected width map width
     33        add     (hl)
     34
     35        ld      d, #0
     36        ld      e, a
     37        ld      a, c
     38        MUL_DE_BY_A_RET_HL
     39        ld      a, b
     40        ADD_A_REG16 h, l
     41        ld      d, h
     42        ld      e, l
     43
     44        ldhl    sp, #6
     45        ld      a,(hl+)         
     46        ld      h,(hl)          
     47        ld      l,a             
     48        add     hl, de
     49        ld      b, h
     50        ld      c, l
     51
     52        ldhl    sp, #2
     53        ld      a, (hl+)        ; d = x
     54        and     #0x1f
     55        ld      d, a
     56        ld      a, (hl)         ; e = y
     57        and     #0x1f
     58        ld      e, a
     59
     60        ldhl    sp, #5
     61        ld      a,(hl-)         ; a = h
     62        ld      h,(hl)          ; h = w
     63        ld      l,a             ; l = h
     64
     65        jr      .set_xy_bkg_submap
     66
     67        ;; set window tile table from bc at xy = de of size wh = hl
     68.set_xy_win_submap::
     69        push    hl              ; store wh
     70        ldh     a,(.LCDC)
     71        and     #LCDCF_WIN9C00
     72        jr      z,.is98
     73        jr      .is9c
     74        ;; set background tile table from (bc) at xy = de of size wh = hl
     75.set_xy_bkg_submap::
     76        push    hl              ; store wh
     77        ldh     a,(.LCDC)
     78        and     #LCDCF_BG9C00
     79        jr      nz,.is9c
     80.is98:
     81        ld      hl,#0x9800
     82        jr      .set_xy_submap
     83.is9c:
     84        ld      hl,#0x9c00
     85        ;; set background tile from (bc) at xy = de, size wh on stack, to vram from address (hl)
     86.set_xy_submap::
     87        push    bc              ; store source
     88
     89        swap    e
     90        rlc     e
     91        ld      a,e
     92        and     #0x03
     93        add     h
     94        ld      b,a
     95        ld      a,#0xe0
     96        and     e
     97        add     d
     98        ld      c,a             ; dest bc = hl + 0x20 * y + x
     99
    100        pop     hl              ; hl = source
    101        pop     de              ; de = wh
    102        push    de              ; store wh
    103        push    bc              ; store dest
    1043$:                             ; copy w tiles
    105        WAIT_STAT
    106        ld      a, (__submap_tile_offset)
    107        add     (hl)
    108        ld      (bc), a
    109        inc     hl
    110        
    111        ld      a, c            ; inc dest and wrap around
    112        and     #0xe0
    113        ld      e, a
    114        ld      a, c
    115        inc     a
    116        and     #0x1f
    117        or      e
    118        ld      c, a
    119
    120        dec     d
    121        jr      nz, 3$
    122
    123        ld      a, (.image_tile_width)
    124        ADD_A_REG16 h, l
    125
    126        pop     bc
    127        pop     de
    128
    129        dec     e
    130        ret     z
    131
    132        push    de
    133
    134        ld      a, b            ; next row and wrap around
    135        and     #0xfc
    136        ld      e, a            ; save high bits
    137
    138        ld      a,#0x20
    139
    140        add     c
    141        ld      c, a
    142        adc     b
    143        sub     c
    144        and     #0x03
    145        or      e               ; restore high bits
    146        ld      b, a
    147
    148        push    bc
    149        
    150        jr      3$