PC-88 z80asmでセミグラフィック

sample.asm

; z88dk / 8801
; z80asm -b -l sample.asm

        org     $b000
start:
        call    crtset
        call    cls

        ld      hl, data
        ld      b, 160
        ld      c, 0            ; x
.loop
        push    hl
        push    bc
        ld      a, 50           ; y = 50 - (hl)
        sub     (hl)
        ld      b, a
        ld      a, (hl)
        add     a, a
        call    line
        pop     bc
        pop     hl
        inc     hl
        inc     c
        djnz    loop
.exit
        di
        halt

crtset:
        ld      hl, $e6b4
        ld      (hl), $98       ; アトリビュート
        inc     hl
        inc     hl
        inc     hl
        inc     hl
        ld      (hl), $00       ; ファンクション・キー表示スイッチ
        inc     hl
        ld      (hl), $ff       ; カラー／白黒スイッチ
        ld      b, 80
        ld      c, 25
        call    $6f6b           ; CRTSET
        ret

cls:
        xor     a
        ld      hl, $f3c8
        ld      de, 40          ; アトリビュート長さ
        ld      c, 25
.clsy
        ld      b, 80
.clsx
        ld      (hl), a
        inc     hl
        djnz    clsx
        add     hl, de
        dec     c
        jr      nz, clsy
        ret

; b=y c=x a=高さ
line:
        dec     a
        ret     m
        push    af
        push    bc
        call    pset
        pop     bc
        pop     af
        inc     b
        jp      line

; b=y c=x
pset:
        ld      a, b            ; de = y & $fc
        and     a, $fc
        ld      e, a
        ld      d, 0

        ld      hl, 0           ; hl = de * 30
        add     hl, de
        add     hl, hl
        add     hl, de
        add     hl, hl
        add     hl, de
        add     hl, hl
        add     hl, de
        add     hl, hl          ; %11110=30倍

        ld      e, c            ; hl += x / 2
        srl     e
        add     hl, de

        ld      a, b            ; a = ((x&1) ? $10 : $01) << (y&3)
        and     a, $03
        ld      b, a
        ld      a, c
        and     1
        ld      a, $01
        jr      z, pset1
        ld      a, $10
.pset1
        dec     b
        jp      m, pset2
        add     a, a
        jr      pset1
.pset2

        ld      de, $f3c8       ; *($f3c8+hl) |= a
        add     hl, de
        or      (hl)
        ld      (hl), a
        ret

data:
        defb    05,05,05,05,05,05,05,05,13,13,13,13,13,13,13,13,13,21,21,21
        defb    21,21,21,21,21,21,21,21,21,21,21,21,21,21,22,22,22,22,22,22
        defb    22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,22,23,23,23,23
        defb    23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23,23
        defb    23,23,23,23,23,23,23,25,25,25,25,25,25,25,25,25,25,25,25,25
        defb    25,25,25,25,25,25,25,25,25,25,25,25,25,23,23,23,23,22,22,22
        defb    21,21,20,20,19,19,19,18,17,17,04,04,04,04,04,04,04,04,04,04
        defb    03,03,03,03,03,03,03,00,00,00,00,00,00,00,00,00,00,05,05,05

bin2t88 SAMPLE b000 sample.bin

mon
h]r
h]gb000