require'vcs'
mappers['2K']()

local tmp = 0x80

section{ "font", align=256 } dc.b
    0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,-- <SPC>
    0x18,0x3c,0x66,0x7e,0x66,0x66,0x66,0x00,-- A
    0x7c,0x66,0x66,0x7c,0x66,0x66,0x7c,0x00,-- B
    0x3c,0x66,0x60,0x60,0x60,0x66,0x3c,0x00,-- C
    0x78,0x6c,0x66,0x66,0x66,0x6c,0x78,0x00,-- D
    0x7e,0x60,0x60,0x78,0x60,0x60,0x7e,0x00,-- E
    0x7e,0x60,0x60,0x78,0x60,0x60,0x60,0x00,-- F
    0x3c,0x66,0x60,0x6e,0x66,0x66,0x3c,0x00,-- G
    0x66,0x66,0x66,0x7e,0x66,0x66,0x66,0x00,-- H
    0x3c,0x18,0x18,0x18,0x18,0x18,0x3c,0x00,-- I
    0x1e,0x0c,0x0c,0x0c,0x0c,0x6c,0x38,0x00,-- J
    0x66,0x6c,0x78,0x70,0x78,0x6c,0x66,0x00,-- K
    0x60,0x60,0x60,0x60,0x60,0x60,0x7e,0x00,-- L
    0x63,0x77,0x7f,0x6b,0x63,0x63,0x63,0x00,-- M
    0x66,0x76,0x7e,0x7e,0x6e,0x66,0x66,0x00,-- N
    0x3c,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- O
    0x7c,0x66,0x66,0x7c,0x60,0x60,0x60,0x00,-- P
    0x3c,0x66,0x66,0x66,0x66,0x3c,0x0e,0x00,-- Q
    0x7c,0x66,0x66,0x7c,0x78,0x6c,0x66,0x00,-- R
    0x3c,0x66,0x60,0x3c,0x06,0x66,0x3c,0x00,-- S
    0x7e,0x18,0x18,0x18,0x18,0x18,0x18,0x00,-- T
    0x66,0x66,0x66,0x66,0x66,0x66,0x3c,0x00,-- U
    0x66,0x66,0x66,0x66,0x66,0x3c,0x18,0x00,-- V
    0x63,0x63,0x63,0x6b,0x7f,0x77,0x63,0x00,-- W
    0x66,0x66,0x3c,0x18,0x3c,0x66,0x66,0x00,-- X
    0x66,0x66,0x66,0x3c,0x18,0x18,0x18,0x00,-- Y
    0x7e,0x06,0x0c,0x18,0x30,0x60,0x7e,0x00 -- Z

charset(" abcdefghijklmnopqrstuvwxyz", \x(x*8))
@@text_hello dc.b "hello world"

local print_txt = tmp+1 -- text pointer, can cross
local print_line_count=tmp -- number of lines to print
local print_ptr = tmp+3 -- array of pointers to the characters
-- a = line count
@@print12
    sta print_line_count
    lda#6 sta NUSIZ0 sta NUSIZ1
    -- set MSB of font character addresses
    lda#font>>8 ldx#23 @_loadfont sta print_ptr,x dex dex bpl _loadfont
    -- position sprites
    samepage
        sta WSYNC
        ldx#6 @_delay dex bne _delay
        sta RESP0 nop sta RESP1 lda#0x70 sta HMP0 lda#0x60 sta HMP1 sta WSYNC sta HMOVE
    end
    @_loop
        -- load text line
        ldx#0 ldy#0 @_loadline lda (print_txt),y sta print_ptr,x inx inx iny cpy#12 bne _loadline
        lda#0x80 sta HMP0 sta HMP1
        ldy#0 samepage @_printline
            sta WSYNC sta HMOVE
            -- first scanline
            lda (print_ptr+2),y sta GRP0 lda (print_ptr+6),y sta GRP1
            lda (print_ptr+22),y tax sleep(6)
            lda (print_ptr+10),y sta GRP0 lda (print_ptr+14),y sta GRP1 lda (print_ptr+18),y sta GRP0 stx GRP1
            sta HMCLR sleep(8) sta HMOVE
            -- second scanline
            lda (print_ptr),y sta GRP0 lda (print_ptr+4),y sta GRP1
            lda (print_ptr+20),y tax lda#0x80 sta HMP0 sta HMP1 nop
            lda (print_ptr+8),y sta GRP0 lda (print_ptr+12),y sta GRP1 lda (print_ptr+16),y sta GRP0 stx GRP1
            iny cpy#8 bne _printline
        end
        dec print_line_count beq _end
        lda print_txt clc adc#12 sta print_txt lda print_txt+1 adc#0 sta print_txt+1
    jmp _loop
@_end
    lda#0 sta GRP0 sta GRP1
    rts

local kernel = function()
    ldx#40 @_blank sta WSYNC dex bne _blank
    setptr(text_hello,print_txt) lda#1 jsr print12
end

@@main
    init()
    lda#0xaa sta COLUP0 sta COLUP1
@_frame
    overscan() vblank() screen(kernel) jmp _frame

;
writebin(filename..'.bin')
writesym(filename..'.sym')
print(stats)