; And Believe Me, I'm Still Alive .include "zp.inc" ; program is ~4k, so from 0xc00 to 0x1C00 LZ4_BUFFER EQU $1C00 ; $1C00 - $5C00, 16k for now UNPACK_BUFFER EQU $5E00 ; $5E00 - $9600, 14k, $3800 ; trying not to hit DOS at $9600 ; Reserve 3 chunks plus spare (14k) NUM_FILES EQU 15 ;============================= ; Setup ;============================= jsr HOME jsr TEXT ; init variables lda #0 sta DRAW_PAGE sta CH sta CV sta DONE_PLAYING sta XPOS sta MB_CHUNK_OFFSET sta DECODE_ERROR ; print detection message lda #mocking_message sta OUTH jsr move_and_print ; print it jsr mockingboard_detect_slot4 ; call detection routine cpx #$1 beq mockingboard_found lda #not_message sta OUTH inc CV jsr move_and_print jmp forever_loop ; and wait forever mockingboard_found: ;============================ ; Init the Mockingboard ;============================ jsr mockingboard_init jsr reset_ay_both jsr clear_ay_both ;========================= ; Setup Interrupt Handler ;========================= ; Vector address goes to 0x3fe/0x3ff ; FIXME: should chain any existing handler lda #interrupt_handler sta $03ff ;============================ ; Enable 50Hz clock on 6522 ;============================ sei ; disable interrupts just in case lda #$40 ; Continuous interrupts, don't touch PB7 sta $C40B ; ACR register lda #$7F ; clear all interrupt flags sta $C40E ; IER register (interrupt enable) lda #$C0 sta $C40D ; IFR: 1100, enable interrupt on timer one oflow sta $C40E ; IER: 1100, enable timer one interrupt lda #$E7 sta $C404 ; write into low-order latch lda #$4f sta $C405 ; write into high-order latch, ; load both values into counter ; clear interrupt and start counting ; 4fe7 / 1e6 = .020s, 50Hz ;============================ ; Draw title screen ;============================ ;=========================== ; clear both screens ;=========================== ; Clear text page0 lda #0 sta DRAW_PAGE lda #(' '+$80) sta clear_all_color+1 jsr clear_all ;================== ; load song ;================== jsr load_song ;============================ ; Init Background ;============================ ;============================ ; Enable 6502 interrupts ;============================ cli ; clear interrupt mask ;============================ ; Loop forever ;============================ main_loop: lda DECODE_ERROR beq check_copy sei brk ; panic if we had an error check_copy: lda COPY_TIME beq check_decompress ; if zero, skip lda #0 sta COPY_OFFSET check_copy_loop: jsr page_copy ;6+3621 inc COPY_OFFSET ; (opt: make subtract?) ; 5 lda #14 ; NOT HEX URGH! cmp COPY_OFFSET bne check_copy_loop lda #0 ; we are done sta COPY_TIME check_decompress: lda DECOMPRESS_TIME beq check_done ; if zero, skip jsr setup_next_subsong ; decompress lda MB_CHUNK_OFFSET sta TIME_TAKEN lda #0 sta DECOMPRESS_TIME check_done: lda #$ff bit DONE_PLAYING beq main_loop ; if was all zeros, loop bmi main_loop ; if high bit set, paused ; bvs minus_song ; if bit 6 set, then left pressed ; else, either song finished or ; right pressed done_play: lda #0 sta DONE_PLAYING forever_loop: jmp forever_loop ;================= ; load our song ;================= load_song: ;========================= ; Init Variables ;========================= lda #$0 sta FRAME_COUNT sta COPY_OFFSET sta DECOMPRESS_TIME sta COPY_TIME sta MB_CHUNK_OFFSET lda #$20 sta DECODER_STATE lda #3 sta CHUNKSIZE ;=========================== ; Load in KRW file ;=========================== lda #krw_file sta INH disk_buff EQU LZ4_BUFFER read_size EQU $4000 jsr read_file ; read KRW file from disk ; Point LZ4 src at proper place ldy #0 lda #>(LZ4_BUFFER+3) sta LZ4_SRC+1 lda #<(LZ4_BUFFER+3) sta LZ4_SRC lda (LZ4_SRC),Y ; get header skip clc adc LZ4_SRC sta LZ4_SRC lda LZ4_SRC+1 adc #0 sta LZ4_SRC+1 lda #UNPACK_BUFFER sta INH ; Decompress first chunks lda #$0 sta COPY_OFFSET sta DECOMPRESS_TIME lda #$3 sta CHUNKSIZE lda #$20 sta DECODER_STATE sta COPY_TIME jsr setup_next_subsong rts ;================= ; next sub-song ;================= setup_next_subsong: ldy #0 lda (LZ4_SRC),Y ; get next size value sta LZ4_END iny lda (LZ4_SRC),Y sta LZ4_END+1 lda #2 ; increment pointer clc adc LZ4_SRC sta LZ4_SRC lda LZ4_SRC+1 adc #0 sta LZ4_SRC+1 jsr lz4_decode ; decode ; tail-call? rts ;============================================== ; plan: takes 256 50Hz to play a chunk ; need to copy 14 256-byte blocks ; PLAY A (copying C) ; PLAY B (copying C) ; PLAY D (decompressing A/B/C) ;======================== ; page copy ;======================== ; want to copy: ; SRC: chunk_buffer+(2*256)+(COPY_OFFSET*3*256) ; DST: chunk_buffer+$2A00+(COPY_OFFSET*256) page_copy: clc ; 2 lda #>(UNPACK_BUFFER+512) ; 3 adc COPY_OFFSET ; 3 adc COPY_OFFSET ; 3 adc COPY_OFFSET ; 3 sta page_copy_loop+2 ; self modify ; 5 lda #>(UNPACK_BUFFER+$2A00) ; 2 adc COPY_OFFSET ; 3 sta page_copy_loop+5 ; self modify ; 5 ldx #$00 ; 2 page_copy_loop: lda $1000,x ; 4 sta $1000,X ; 5 inx ; 2 bne page_copy_loop ; 2nt/3 rts ; 6 ;====================== ; 2+14*256+6+29= 3621 ;========== ; filenames ;========== krw_file: .asciiz "SA.KRW" ;========= ;routines ;========= .include "../asm_routines/gr_offsets.s" .include "../asm_routines/text_print.s" .include "../asm_routines/mockingboard_a.s" .include "../asm_routines/gr_fast_clear.s" .include "../asm_routines/pageflip.s" .include "../asm_routines/gr_setpage.s" .include "../asm_routines/dos33_routines.s" .include "../asm_routines/lz4_decode.s" .include "../asm_routines/keypress_minimal.s" .include "interrupt_handler.s" ;========= ; strings ;========= mocking_message: .asciiz "LOOKING FOR MOCKINGBOARD IN SLOT #4" not_message: .byte "NOT " loading_message: .asciiz "LOADING" .include "ascii_art.inc"