gbsomething/source/home/text.asm

include "charmap.inc"
include "video.inc"

section "home/text.asm@data", rom0
gfx_font:
incbin "assets/tetrisfont.1bpp"
.end

section "home/text.asm@vram", vram

ds $2D tiles
v_font_dash_period: ds 2 tiles
ds $1 tiles
v_font_numbers: ds 10 tiles
ds $7 tiles
v_font_uppercase: ds 26 tiles
ds $6 tiles
v_font_lowercase: ds 26 tiles

section "home/text.asm", rom0

prints::
; hl: String
; de: Tilemap position
    ld a, [hli]
    cp "$"
    ret z
    call lcd_blank_wait  ; TODO: Really hackish.
    ld [de], a
    inc de
    jr prints

print_dec_3digit::
; a: Number
; de: Tilemap positon
    push af
    call lcd_blank_wait
    xor a
    ld [de], a
    inc de
    ld [de], a
    inc de
    ld [de], a
    pop af

    ld l, 3
.loop
    ld c, 10
    call divide
    add "0"
    call lcd_blank_wait
    ld [de], a
    ld a, b
    and a
    ret z
    dec de
    dec l
    jr nz, .loop
    ret

print_hex_4digit::
; hl: Number
; de: Tilemap position
    ld a, h
    swap a
    call print_hex_1digit
    ld a, h
    call print_hex_1digit
    ld a, l
    swap a
    call print_hex_1digit
    ld a, l
    jr print_hex_1digit

print_hex_2digit::
; a: Number
; de: Tilemap position
    ld b, a
    swap a
    call print_hex_1digit
    ld a, b
    jr print_hex_1digit

print_hex_1digit:
    and $f
    add "0"
    cp "9" + 1
    jr c, .skip
    add "A" - "0" - $a
.skip
    call lcd_blank_wait
    ld [de], a
    inc de
    ret

font_load::
    ld hl, gfx_font
    ld de, v_font_numbers
    ld bc, (10 tiles) / 2
    call memcpy_double
    ld de, v_font_uppercase
    ld bc, (26 tiles) / 2
    call memcpy_double
    ld hl, gfx_font + (10 tiles) / 2
    ld de, v_font_lowercase
    ld bc, (26 tiles) / 2
    call memcpy_double
    ld de, v_font_dash_period + (1 tiles)
    ld bc, (1 tiles) / 2
    call memcpy_double
    ld de, v_font_dash_period
    ld bc, (1 tiles) / 2
    jp memcpy_double