148 lines
2.6 KiB
ArmAsm
148 lines
2.6 KiB
ArmAsm
; VMW Chiptune Player
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.include "zp.inc"
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;=============================
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; Setup
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;=============================
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; init variables
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lda #0
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sta DONE_PLAYING
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sta MB_CHUNK_OFFSET
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jsr mockingboard_detect_slot4 ; call detection routine
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;============================
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; Init the Mockingboard
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;============================
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jsr mockingboard_init
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jsr reset_ay_both
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jsr clear_ay_both
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;=========================
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; Setup Interrupt Handler
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;=========================
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; Vector address goes to 0x3fe/0x3ff
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; FIXME: should chain any existing handler
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.ifdef NOIRQ
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.else
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lda #<interrupt_handler
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sta $03fe
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lda #>interrupt_handler
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sta $03ff
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.endif
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;============================
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; Enable 50Hz clock on 6522
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;============================
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.ifdef NOIRQ
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.else
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sei ; disable interrupts just in case
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lda #$40 ; Continuous interrupts, don't touch PB7
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sta $C40B ; ACR register
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lda #$7F ; clear all interrupt flags
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sta $C40E ; IER register (interrupt enable)
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lda #$C0
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sta $C40D ; IFR: 1100, enable interrupt on timer one oflow
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sta $C40E ; IER: 1100, enable timer one interrupt
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.ifdef F25HZ
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lda #$40
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sta $C404 ; write into low-order latch
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lda #$9c
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sta $C405 ; write into high-order latch,
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; load both values into counter
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; clear interrupt and start counting
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; 9c40 / 1e6 = .040s, 25Hz
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.else
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lda #$E7
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sta $C404 ; write into low-order latch
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lda #$4f
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sta $C405 ; write into high-order latch,
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; load both values into counter
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; clear interrupt and start counting
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; 4fe7 / 1e6 = .020s, 50Hz
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.endif
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.endif
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;==================
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; load first song
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;==================
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jsr new_song
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;============================
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; Enable 6502 interrupts
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;============================
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.ifdef NOIRQ
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.else
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cli ; clear interrupt mask
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.endif
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;============================
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; Loop forever
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;============================
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main_loop:
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.ifdef NOIRQ
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jsr interrupt_handler
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lda #85
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jsr WAIT ; wait 20ms-xms
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.else
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.endif
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jmp main_loop
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;=================
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; load a new song
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;=================
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new_song:
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;=========================
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; Init Variables
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;=========================
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lda #$0
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sta MB_CHUNK_OFFSET
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lda #3
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sta CHUNKSIZE
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;===========================
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; Load in KRW file
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;===========================
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lda #<UNPACK_BUFFER ; set input pointer
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sta INL
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lda #>UNPACK_BUFFER
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sta INH
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; Decompress first chunks
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lda #$3
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sta CHUNKSIZE
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rts
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;=========
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;routines
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;=========
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.include "mockingboard_a.s"
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.include "interrupt_handler.s"
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.align 256
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UNPACK_BUFFER:
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.incbin "sdemo.raw"
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