cscg22-gearboy

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

putchar.s (2428B)

      1        .include        "global.s"
      2
      3        .title  "putchar"
      4        .module putchar
      5
      6        .globl  font_current, font_set, font_load_ibm
      7        .globl  .scroll_viewport
      8
      9        ; Structure offsets
     10        sfont_handle_sizeof     = 3
     11        sfont_handle_font       = 1
     12        sfont_handle_first_tile = 0
     13
     14        ; Encoding types - lower 2 bits of font
     15        FONT_256ENCODING        = 0
     16        FONT_128ENCODING        = 1
     17        FONT_NOENCODING         = 2
     18
     19        .area   _INITIALIZED
     20        ; The current font
     21.curx::
     22        .ds     1
     23.cury::
     24        .ds     1
     25
     26        .area   _INITIALIZER
     27        .db     #.SCREEN_X_OFS  ; .curx
     28        .db     #.SCREEN_Y_OFS  ; .cury
     29
     30        .area   _HOME
     31
     32_setchar::
     33_putchar::
     34        pop hl
     35        pop de
     36        push de
     37        push hl
     38
     39	ld a, e
     40        cp #.CR
     41        jr nz, 0$
     42
     43        ld a, #.SCREEN_X_OFS
     44        ld (.curx), a
     45        jp 2$
     460$:
     47        ld hl, (font_current+sfont_handle_font)
     48        ld a, h
     49        or l 
     50        jr nz, 6$
     51        
     52        push de
     53        call font_load_ibm
     54        ld a, h
     55        or l
     56        ret z 
     57        call font_set
     58        pop de
     59        ld hl, (font_current+sfont_handle_font)
     606$:
     61        ld a, (hl)
     62        and #3
     63        cp #FONT_NOENCODING
     64        jr z, 4$
     65        inc hl
     66        inc hl
     67        ld d, #0
     68        add hl, de
     69        ld e, (hl)
     704$:
     71        ld a, (font_current)
     72        add a, e
     73        ld e, a
     74
     75        ld a, (.cury)
     76        ld l, a
     77        ld h, #0
     78        add hl, hl
     79        add hl, hl
     80        add hl, hl
     81        add hl, hl
     82        add hl, hl
     83        add hl, hl
     84        ld a, (.curx)
     85        add a
     86        add l
     87        ld l, a
     88        adc h
     89        sub l
     90        ld h, a
     91
     92        ld bc, #.VDP_TILEMAP
     93        add hl, bc
     94
     95        DISABLE_VBLANK_COPY     ; switch OFF copy shadow SAT
     96        WRITE_VDP_CMD_HL
     97
     98        ld a, e
     99        out (.VDP_DATA), a
    100        VDP_DELAY
    101        xor a
    102        out (.VDP_DATA), a
    103
    104        ENABLE_VBLANK_COPY         ; switch ON copy shadow SAT
    105
    106        ld a, (.curx)
    107        inc a
    108        cp #(.SCREEN_X_OFS + .SCREEN_WIDTH)
    109        jr c, 5$
    110        ld a, #.SCREEN_X_OFS
    1115$:
    112        ld (.curx), a
    113        ret nz
    1142$:
    115        ld a, (.cury)
    116        inc a
    117        cp #(.SCREEN_Y_OFS + .SCREEN_HEIGHT)
    118        jr c, 3$
    119        ld a, #(.SCREEN_Y_OFS + .SCREEN_HEIGHT - 1)
    120        ld (.cury), a
    121
    122        call .scroll_viewport
    123        ret
    1243$:
    125        ld (.cury), a
    126        ret