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601 lines
17 KiB
C++
601 lines
17 KiB
C++
// Squawk Soft-Synthesizer Library for Arduino
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//
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// Davey Taylor 2013
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// d.taylor@arduino.cc
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#include "Squawk.h"
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// Period range, used for clamping
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#define PERIOD_MIN 28
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#define PERIOD_MAX 3424
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// Convenience macros
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#define LO4(V) ((V) & 0x0F)
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#define HI4(V) (((V) & 0xF0) >> 4)
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#define MIN(A, B) ((A) < (B) ? (A) : (B))
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#define MAX(A, B) ((A) > (B) ? (A) : (B))
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#define FREQ(PERIOD) (tuning_long / (PERIOD))
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// SquawkStream class for PROGMEM data
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class StreamROM : public SquawkStream {
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private:
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uint8_t *p_start;
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uint8_t *p_cursor;
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public:
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StreamROM(const uint8_t *p_rom = NULL) { p_start = p_cursor = (uint8_t*)p_rom; }
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uint8_t read() { return pgm_read_byte(p_cursor++); }
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void seek(size_t offset) { p_cursor = p_start + offset; }
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};
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// Oscillator memory
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typedef struct {
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uint8_t fxp;
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uint8_t offset;
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uint8_t mode;
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} pto_t;
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// Deconstructed cell
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typedef struct {
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uint8_t fxc, fxp, ixp;
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} cel_t;
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// Effect memory
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typedef struct {
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int8_t volume;
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uint8_t port_speed;
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uint16_t port_target;
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bool glissando;
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pto_t vibr;
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pto_t trem;
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uint16_t period;
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uint8_t param;
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} fxm_t;
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// Locals
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static uint8_t order_count;
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static uint8_t order[64];
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static uint8_t speed;
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static uint8_t tick;
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static uint8_t ix_row;
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static uint8_t ix_order;
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static uint8_t ix_nextrow;
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static uint8_t ix_nextorder;
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static uint8_t row_delay;
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static fxm_t fxm[4];
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static cel_t cel[4];
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static uint32_t tuning_long;
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static uint16_t sample_rate;
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static float tuning = 1.0;
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static uint16_t tick_rate = 50;
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static SquawkStream *stream;
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static uint16_t stream_base;
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static StreamROM rom;
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// Imports
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extern intptr_t squawk_register;
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extern uint16_t cia;
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// Exports
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osc_t osc[4];
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uint8_t pcm = 128;
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// ProTracker period tables
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uint16_t period_tbl[84] PROGMEM = {
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3424, 3232, 3048, 2880, 2712, 2560, 2416, 2280, 2152, 2032, 1920, 1814,
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1712, 1616, 1524, 1440, 1356, 1280, 1208, 1140, 1076, 1016, 960, 907,
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856, 808, 762, 720, 678, 640, 604, 570, 538, 508, 480, 453,
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428, 404, 381, 360, 339, 320, 302, 285, 269, 254, 240, 226,
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214, 202, 190, 180, 170, 160, 151, 143, 135, 127, 120, 113,
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107, 101, 95, 90, 85, 80, 75, 71, 67, 63, 60, 56,
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53, 50, 47, 45, 42, 40, 37, 35, 33, 31, 30, 28,
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};
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// ProTracker sine table
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int8_t sine_tbl[32] PROGMEM = {
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0x00, 0x0C, 0x18, 0x25, 0x30, 0x3C, 0x47, 0x51, 0x5A, 0x62, 0x6A, 0x70, 0x76, 0x7A, 0x7D, 0x7F,
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0x7F, 0x7F, 0x7D, 0x7A, 0x76, 0x70, 0x6A, 0x62, 0x5A, 0x51, 0x47, 0x3C, 0x30, 0x25, 0x18, 0x0C,
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};
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// Squawk object
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SquawkSynth Squawk;
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// Look up or generate waveform for ProTracker vibrato/tremolo oscillator
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static int8_t do_osc(pto_t *p_osc) {
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int8_t sample = 0;
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int16_t mul;
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switch(p_osc->mode & 0x03) {
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case 0: // Sine
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sample = pgm_read_byte(&sine_tbl[(p_osc->offset) & 0x1F]);
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if(p_osc->offset & 0x20) sample = -sample;
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break;
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case 1: // Square
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sample = (p_osc->offset & 0x20) ? 127 : -128;
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break;
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case 2: // Saw
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sample = -(p_osc->offset << 2);
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break;
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case 3: // Noise (random)
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sample = rand();
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break;
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}
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mul = sample * LO4(p_osc->fxp);
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p_osc->offset = (p_osc->offset + HI4(p_osc->fxp));
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return mul >> 6;
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}
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// Calculates and returns arpeggio period
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// Essentially finds period of current note + halftones
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static inline uint16_t arpeggio(uint8_t ch, uint8_t halftones) {
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uint8_t n;
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for(n = 0; n != 47; n++) {
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if(fxm[ch].period >= pgm_read_word(&period_tbl[n])) break;
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}
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return pgm_read_word(&period_tbl[MIN(n + halftones, 47)]);
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}
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// Calculates and returns glissando period
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// Essentially snaps a sliding frequency to the closest note
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static inline uint16_t glissando(uint8_t ch) {
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uint8_t n;
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uint16_t period_h, period_l;
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for(n = 0; n != 47; n++) {
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period_l = pgm_read_word(&period_tbl[n]);
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period_h = pgm_read_word(&period_tbl[n + 1]);
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if(fxm[ch].period < period_l && fxm[ch].period >= period_h) {
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if(period_l - fxm[ch].period <= fxm[ch].period - period_h) {
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period_h = period_l;
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}
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break;
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}
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}
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return period_h;
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}
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// Tunes Squawk to a different frequency
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void SquawkSynth::tune(float new_tuning) {
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tuning = new_tuning;
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tuning_long = (long)(((double)3669213184.0 / (double)sample_rate) * (double)tuning);
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}
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// Sets tempo
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void SquawkSynth::tempo(uint16_t new_tempo) {
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tick_rate = new_tempo;
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cia = sample_rate / tick_rate; // not atomic?
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}
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// Initializes Squawk
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// Sets up the selected port, and the sample grinding ISR
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void SquawkSynth::begin(uint16_t hz) {
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word isr_rr;
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sample_rate = hz;
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tuning_long = (long)(((double)3669213184.0 / (double)sample_rate) * (double)tuning);
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cia = sample_rate / tick_rate;
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if(squawk_register == (intptr_t)&OCR0A) {
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// Squawk uses PWM on OCR0A/PD5(ATMega328/168)/PB7(ATMega32U4)
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#ifdef __AVR_ATmega32U4__
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DDRB |= 0b10000000; // TODO: FAIL on 32U4
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#else
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DDRD |= 0b01000000;
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#endif
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TCCR0A = 0b10000011; // Fast-PWM 8-bit
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TCCR0B = 0b00000001; // 62500Hz
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OCR0A = 0x7F;
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} else if(squawk_register == (intptr_t)&OCR0B) {
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// Squawk uses PWM on OCR0B/PC5(ATMega328/168)/PD0(ATMega32U4)
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#ifdef __AVR_ATmega32U4__
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DDRD |= 0b00000001;
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#else
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DDRD |= 0b00100000;
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#endif // Set timer mode to
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TCCR0A = 0b00100011; // Fast-PWM 8-bit
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TCCR0B = 0b00000001; // 62500Hz
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OCR0B = 0x7F;
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#ifdef OCR2A
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} else if(squawk_register == (intptr_t)&OCR2A) {
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// Squawk uses PWM on OCR2A/PB3
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DDRB |= 0b00001000; // Set timer mode to
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TCCR2A = 0b10000011; // Fast-PWM 8-bit
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TCCR2B = 0b00000001; // 62500Hz
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OCR2A = 0x7F;
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#endif
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#ifdef OCR2B
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} else if(squawk_register == (intptr_t)&OCR2B) {
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// Squawk uses PWM on OCR2B/PD3
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DDRD |= 0b00001000; // Set timer mode to
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TCCR2A = 0b00100011; // Fast-PWM 8-bit
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TCCR2B = 0b00000001; // 62500Hz
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OCR2B = 0x7F;
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#endif
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#ifdef OCR3AL
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} else if(squawk_register == (intptr_t)&OCR3AL) {
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// Squawk uses PWM on OCR3AL/PC6
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DDRC |= 0b01000000; // Set timer mode to
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TCCR3A = 0b10000001; // Fast-PWM 8-bit
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TCCR3B = 0b00001001; // 62500Hz
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OCR3AH = 0x00;
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OCR3AL = 0x7F;
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#endif
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} else if(squawk_register == (intptr_t)&SPDR) {
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// NOT YET SUPPORTED
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// Squawk uses external DAC via SPI
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// TODO: Configure SPI
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// TODO: Needs SS toggle in sample grinder
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} else if(squawk_register == (intptr_t)&PORTB) {
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// NOT YET SUPPORTED
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// Squawk uses resistor ladder on PORTB
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// TODO: Needs shift right in sample grinder
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DDRB = 0b11111111;
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} else if(squawk_register == (intptr_t)&PORTC) {
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// NOT YET SUPPORTED
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// Squawk uses resistor ladder on PORTC
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// TODO: Needs shift right in sample grinder
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DDRC = 0b11111111;
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}
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// Seed LFSR (needed for noise)
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osc[3].freq = 0x2000;
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// Set up ISR to run at sample_rate (may not be exact)
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isr_rr = F_CPU / sample_rate;
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TCCR1A = 0b00000000; // Set timer mode
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TCCR1B = 0b00001001;
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OCR1AH = isr_rr >> 8; // Set freq
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OCR1AL = isr_rr & 0xFF;
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}
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// Decrunches a 9 byte row into a useful data
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static void decrunch_row() {
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uint8_t data;
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// Initial decrunch
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stream->seek(stream_base + ((order[ix_order] << 6) + ix_row) * 9);
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data = stream->read(); cel[0].fxc = data << 0x04;
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cel[1].fxc = data & 0xF0;
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data = stream->read(); cel[0].fxp = data;
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data = stream->read(); cel[1].fxp = data;
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data = stream->read(); cel[2].fxc = data << 0x04;
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cel[3].fxc = data >> 0x04;
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data = stream->read(); cel[2].fxp = data;
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data = stream->read(); cel[3].fxp = data;
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data = stream->read(); cel[0].ixp = data;
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data = stream->read(); cel[1].ixp = data;
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data = stream->read(); cel[2].ixp = data;
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// Decrunch extended effects
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if(cel[0].fxc == 0xE0) { cel[0].fxc |= cel[0].fxp >> 4; cel[0].fxp &= 0x0F; }
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if(cel[1].fxc == 0xE0) { cel[1].fxc |= cel[1].fxp >> 4; cel[1].fxp &= 0x0F; }
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if(cel[2].fxc == 0xE0) { cel[2].fxc |= cel[2].fxp >> 4; cel[2].fxp &= 0x0F; }
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// Decrunch cell 3 ghetto-style
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cel[3].ixp = ((cel[3].fxp & 0x80) ? 0x00 : 0x7F) | ((cel[3].fxp & 0x40) ? 0x80 : 0x00);
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cel[3].fxp &= 0x3F;
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switch(cel[3].fxc) {
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case 0x02:
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case 0x03: if(cel[3].fxc & 0x01) cel[3].fxp |= 0x40; cel[3].fxp = (cel[3].fxp >> 4) | (cel[3].fxp << 4); cel[3].fxc = 0x70; break;
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case 0x01: if(cel[3].fxp & 0x08) cel[3].fxp = (cel[3].fxp & 0x07) << 4; cel[3].fxc = 0xA0; break;
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case 0x04: cel[3].fxc = 0xC0; break;
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case 0x05: cel[3].fxc = 0xB0; break;
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case 0x06: cel[3].fxc = 0xD0; break;
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case 0x07: cel[3].fxc = 0xF0; break;
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case 0x08: cel[3].fxc = 0xE7; break;
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case 0x09: cel[3].fxc = 0xE9; break;
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case 0x0A: cel[3].fxc = (cel[3].fxp & 0x08) ? 0xEA : 0xEB; cel[3].fxp &= 0x07; break;
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case 0x0B: cel[3].fxc = (cel[3].fxp & 0x10) ? 0xED : 0xEC; cel[3].fxp &= 0x0F; break;
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case 0x0C: cel[3].fxc = 0xEE; break;
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}
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// Apply generic effect parameter memory
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uint8_t ch;
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cel_t *p_cel = cel;
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fxm_t *p_fxm = fxm;
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for(ch = 0; ch != 4; ch++) {
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uint8_t fx = p_cel->fxc;
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if(fx == 0x10 || fx == 0x20 || fx == 0xE1 || fx == 0xE2 || fx == 0x50 || fx == 0x60 || fx == 0xA0) {
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if(p_cel->fxp) {
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p_fxm->param = p_cel->fxp;
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} else {
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p_cel->fxp = p_fxm->param;
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}
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}
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p_cel++; p_fxm++;
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}
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}
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// Resets playback
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static void playroutine_reset() {
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memset(fxm, 0, sizeof(fxm));
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tick = 0;
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ix_row = 0;
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ix_order = 0;
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ix_nextrow = 0xFF;
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ix_nextorder = 0xFF;
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row_delay = 0;
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speed = 6;
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decrunch_row();
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}
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// Start grinding samples
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void SquawkSynth::play() {
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TIMSK1 = 1 << OCIE1A; // Enable interrupt
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}
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// Load a melody stream and start grinding samples
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void SquawkSynth::play(SquawkStream *melody) {
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uint8_t n;
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pause();
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stream = melody;
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stream->seek(0);
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n = stream->read();
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if(n == 'S') {
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// Squawk SD file
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stream->seek(4);
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stream_base = stream->read() << 8;
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stream_base |= stream->read();
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stream_base += 6;
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} else {
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// Squawk ROM array
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stream_base = 1;
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}
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stream->seek(stream_base);
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order_count = stream->read();
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if(order_count <= 64) {
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stream_base += order_count + 1;
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for(n = 0; n < order_count; n++) order[n] = stream->read();
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playroutine_reset();
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play();
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} else {
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order_count = 0;
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}
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}
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// Load a melody in PROGMEM and start grinding samples
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void SquawkSynth::play(const uint8_t *melody) {
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pause();
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rom = StreamROM(melody);
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play(&rom);
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}
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// Pause playback
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void SquawkSynth::pause() {
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TIMSK1 = 0; // Disable interrupt
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}
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// Stop playing, unload melody
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void SquawkSynth::stop() {
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pause();
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order_count = 0; // Unload melody
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}
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// Progress module by one tick
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void squawk_playroutine() {
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static bool lockout = false;
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if(!order_count) return;
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// Protect from re-entry via ISR
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cli();
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if(lockout) {
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sei();
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return;
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}
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lockout = true;
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sei();
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// Handle row delay
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if(row_delay) {
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if(tick == 0) row_delay--;
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// Advance tick
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if(++tick == speed) tick = 0;
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} else {
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// Quick pointer access
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fxm_t *p_fxm = fxm;
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osc_t *p_osc = osc;
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cel_t *p_cel = cel;
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// Temps
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uint8_t ch, fx, fxp;
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bool pattern_jump = false;
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uint8_t ix_period;
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for(ch = 0; ch != 4; ch++) {
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uint8_t temp;
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// Local register copy
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fx = p_cel->fxc;
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fxp = p_cel->fxp;
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ix_period = p_cel->ixp;
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// If first tick
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if(tick == (fx == 0xED ? fxp : 0)) {
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// Reset volume
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if(ix_period & 0x80) p_osc->vol = p_fxm->volume = 0x20;
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if((ix_period & 0x7F) != 0x7F) {
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// Reset oscillators (unless continous flag set)
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if((p_fxm->vibr.mode & 0x4) == 0x0) p_fxm->vibr.offset = 0;
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if((p_fxm->trem.mode & 0x4) == 0x0) p_fxm->trem.offset = 0;
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// Cell has note
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if(fx == 0x30 || fx == 0x50) {
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// Tone-portamento effect setup
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p_fxm->port_target = pgm_read_word(&period_tbl[ix_period & 0x7F]);
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} else {
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// Set required effect memory parameters
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p_fxm->period = pgm_read_word(&period_tbl[ix_period & 0x7F]);
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// Start note
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if(ch != 3) p_osc->freq = FREQ(p_fxm->period);
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}
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}
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// Effects processed when tick = 0
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switch(fx) {
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case 0x30: // Portamento
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if(fxp) p_fxm->port_speed = fxp;
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break;
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case 0xB0: // Jump to pattern
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ix_nextorder = (fxp >= order_count ? 0x00 : fxp);
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ix_nextrow = 0;
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pattern_jump = true;
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break;
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case 0xC0: // Set volume
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p_osc->vol = p_fxm->volume = MIN(fxp, 0x20);
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break;
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case 0xD0: // Jump to row
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if(!pattern_jump) ix_nextorder = ((ix_order + 1) >= order_count ? 0x00 : ix_order + 1);
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pattern_jump = true;
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ix_nextrow = (fxp > 63 ? 0 : fxp);
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break;
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case 0xF0: // Set speed, BPM(CIA) not supported
|
|
if(fxp <= 0x20) speed = fxp;
|
|
break;
|
|
case 0x40: // Vibrato
|
|
if(fxp) p_fxm->vibr.fxp = fxp;
|
|
break;
|
|
case 0x70: // Tremolo
|
|
if(fxp) p_fxm->trem.fxp = fxp;
|
|
break;
|
|
case 0xE1: // Fine slide up
|
|
if(ch != 3) {
|
|
p_fxm->period = MAX(p_fxm->period - fxp, PERIOD_MIN);
|
|
p_osc->freq = FREQ(p_fxm->period);
|
|
}
|
|
break;
|
|
case 0xE2: // Fine slide down
|
|
if(ch != 3) {
|
|
p_fxm->period = MIN(p_fxm->period + fxp, PERIOD_MAX);
|
|
p_osc->freq = FREQ(p_fxm->period);
|
|
}
|
|
break;
|
|
case 0xE3: // Glissando control
|
|
p_fxm->glissando = (fxp != 0);
|
|
break;
|
|
case 0xE4: // Set vibrato waveform
|
|
p_fxm->vibr.mode = fxp;
|
|
break;
|
|
case 0xE7: // Set tremolo waveform
|
|
p_fxm->trem.mode = fxp;
|
|
break;
|
|
case 0xEA: // Fine volume slide up
|
|
p_osc->vol = p_fxm->volume = MIN(p_fxm->volume + fxp, 0x20);
|
|
break;
|
|
case 0xEB: // Fine volume slide down
|
|
p_osc->vol = p_fxm->volume = MAX(p_fxm->volume - fxp, 0);
|
|
break;
|
|
case 0xEE: // Delay
|
|
row_delay = fxp;
|
|
break;
|
|
}
|
|
} else {
|
|
|
|
// Effects processed when tick > 0
|
|
switch(fx) {
|
|
case 0x10: // Slide up
|
|
if(ch != 3) {
|
|
p_fxm->period = MAX(p_fxm->period - fxp, PERIOD_MIN);
|
|
p_osc->freq = FREQ(p_fxm->period);
|
|
}
|
|
break;
|
|
case 0x20: // Slide down
|
|
if(ch != 3) {
|
|
p_fxm->period = MIN(p_fxm->period + fxp, PERIOD_MAX);
|
|
p_osc->freq = FREQ(p_fxm->period);
|
|
}
|
|
break;
|
|
/*
|
|
// Just feels... ugly
|
|
case 0xE9: // Retrigger note
|
|
temp = tick; while(temp >= fxp) temp -= fxp;
|
|
if(!temp) {
|
|
if(ch == 3) {
|
|
p_osc->freq = p_osc->phase = 0x2000;
|
|
} else {
|
|
p_osc->phase = 0;
|
|
}
|
|
}
|
|
break;
|
|
*/
|
|
case 0xEC: // Note cut
|
|
if(fxp == tick) p_osc->vol = 0x00;
|
|
break;
|
|
default: // Multi-effect processing
|
|
|
|
// Portamento
|
|
if(ch != 3 && (fx == 0x30 || fx == 0x50)) {
|
|
if(p_fxm->period < p_fxm->port_target) p_fxm->period = MIN(p_fxm->period + p_fxm->port_speed, p_fxm->port_target);
|
|
else p_fxm->period = MAX(p_fxm->period - p_fxm->port_speed, p_fxm->port_target);
|
|
if(p_fxm->glissando) p_osc->freq = FREQ(glissando(ch));
|
|
else p_osc->freq = FREQ(p_fxm->period);
|
|
}
|
|
|
|
// Volume slide
|
|
if(fx == 0x50 || fx == 0x60 || fx == 0xA0) {
|
|
if((fxp & 0xF0) == 0) p_fxm->volume -= (LO4(fxp));
|
|
if((fxp & 0x0F) == 0) p_fxm->volume += (HI4(fxp));
|
|
p_osc->vol = p_fxm->volume = MAX(MIN(p_fxm->volume, 0x20), 0);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Normal play and arpeggio
|
|
if(fx == 0x00) {
|
|
if(ch != 3) {
|
|
temp = tick; while(temp > 2) temp -= 2;
|
|
if(temp == 0) {
|
|
|
|
// Reset
|
|
p_osc->freq = FREQ(p_fxm->period);
|
|
} else if(fxp) {
|
|
|
|
// Arpeggio
|
|
p_osc->freq = FREQ(arpeggio(ch, (temp == 1 ? HI4(fxp) : LO4(fxp))));
|
|
}
|
|
}
|
|
} else if(fx == 0x40 || fx == 0x60) {
|
|
|
|
// Vibrato
|
|
if(ch != 3) p_osc->freq = FREQ((p_fxm->period + do_osc(&p_fxm->vibr)));
|
|
} else if(fx == 0x70) {
|
|
int8_t trem = p_fxm->volume + do_osc(&p_fxm->trem);
|
|
p_osc->vol = MAX(MIN(trem, 0x20), 0);
|
|
}
|
|
|
|
// Next channel
|
|
p_fxm++; p_cel++; p_osc++;
|
|
}
|
|
|
|
// Advance tick
|
|
if(++tick == speed) tick = 0;
|
|
|
|
// Advance playback
|
|
if(tick == 0) {
|
|
if(++ix_row == 64) {
|
|
ix_row = 0;
|
|
if(++ix_order >= order_count) ix_order = 0;
|
|
}
|
|
// Forced order/row
|
|
if( ix_nextorder != 0xFF ) {
|
|
ix_order = ix_nextorder;
|
|
ix_nextorder = 0xFF;
|
|
}
|
|
if( ix_nextrow != 0xFF ) {
|
|
ix_row = ix_nextrow;
|
|
ix_nextrow = 0xFF;
|
|
}
|
|
decrunch_row();
|
|
}
|
|
|
|
}
|
|
|
|
lockout = false;
|
|
} |