mirror of https://github.com/noisymime/Arduino.git
265 lines
10 KiB
C++
265 lines
10 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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#ifndef _SQUAWK_H_
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#define _SQUAWK_H_
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#include <stddef.h>
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#include <inttypes.h>
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#include "Arduino.h"
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#define Melody const uint8_t PROGMEM
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class SquawkStream {
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public:
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virtual ~SquawkStream() = 0;
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virtual uint8_t read() = 0;
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virtual void seek(size_t offset) = 0;
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};
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inline SquawkStream::~SquawkStream() { }
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class SquawkSynth {
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protected:
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// Load and play specified melody
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void play(SquawkStream *melody);
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public:
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SquawkSynth() {};
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// Initialize Squawk to generate samples at sample_rate Hz
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void begin(uint16_t sample_rate);
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// Load and play specified melody
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// melody needs to point to PROGMEM data
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void play(const uint8_t *melody);
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// Resume currently loaded melody (or enable direct osc manipulation by sketch)
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void play();
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// Pause playback
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void pause();
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// Stop playback (unloads song)
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void stop();
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// Tune Squawk to a different frequency - default is 1.0
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void tune(float tuning);
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// Change the tempo - default is 50
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void tempo(uint16_t tempo);
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};
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extern SquawkSynth Squawk;
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// oscillator structure
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typedef struct {
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uint8_t vol;
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uint16_t freq;
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uint16_t phase;
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} osc_t;
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typedef osc_t Oscillator;
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// oscillator memory
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extern osc_t osc[4];
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extern uint8_t pcm;
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// channel 0 is pulse wave @ 25% duty
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// channel 1 is square wave
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// channel 2 is triangle wave
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// channel 3 is noise
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// For channel 3, freq is used as part of its LFSR and should not be changed.
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// LFSR: Linear feedback shift register, a method of producing a
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// pseudo-random bit sequence, used to generate nasty noise.
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#ifdef __AVR_ATmega32U4__
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// Supported configurations for ATmega32U4
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#define SQUAWK_PWM_PIN5 OCR3AL
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#define SQUAWK_PWM_PIN11 OCR0A
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#define SQUAWK_PWM_PIN3 OCR0B
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/*
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// NOT SUPPORTED YET
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#define SQUAWK_PWM_PIN6 OCR4D
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#define SQUAWK_PWM_PIN9 OCR4B
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#define SQUAWK_PWM_PIN10 OCR4B
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*/
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#endif
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#ifdef __AVR_ATmega168__
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// Supported configurations for ATmega168
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#define SQUAWK_PWM_PIN6 OCR0A
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#define SQUAWK_PWM_PIN5 OCR0B
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#define SQUAWK_PWM_PIN11 OCR2A
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#define SQUAWK_PWM_PIN3 OCR2B
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#endif
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#ifdef __AVR_ATmega328P__
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// Supported configurations for ATmega328P
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#define SQUAWK_PWM_PIN6 OCR0A
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#define SQUAWK_PWM_PIN5 OCR0B
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#define SQUAWK_PWM_PIN11 OCR2A
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#define SQUAWK_PWM_PIN3 OCR2B
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#endif
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/*
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// NOT SUPPORTED YET
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#define SQUAWK_SPI SPDR
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#define SQUAWK_RLD_PORTB PORTB
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#define SQUAWK_RLD_PORTC PORTC
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*/
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extern void squawk_playroutine() asm("squawk_playroutine");
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// SAMPLE GRINDER
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// generates samples and updates oscillators
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// uses 132 cycles (not counting playroutine)
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// ~1/3 CPU @ 44kHz on 16MHz
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#define SQUAWK_CONSTRUCT_ISR(TARGET_REGISTER) \
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uint16_t cia, cia_count; \
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intptr_t squawk_register = (intptr_t)&TARGET_REGISTER; \
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ISR(TIMER1_COMPA_vect, ISR_NAKED) { \
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asm volatile( \
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"push r2 " "\n\t" \
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"in r2, __SREG__ " "\n\t" \
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"push r18 " "\n\t" \
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"push r27 " "\n\t" \
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"push r26 " "\n\t" \
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"push r0 " "\n\t" \
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"push r1 " "\n\t" \
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\
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"lds r18, osc+2*%[mul]+%[fre] " "\n\t" \
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"lds r0, osc+2*%[mul]+%[pha] " "\n\t" \
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"add r0, r18 " "\n\t" \
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"sts osc+2*%[mul]+%[pha], r0 " "\n\t" \
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"lds r18, osc+2*%[mul]+%[fre]+1" "\n\t" \
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"lds r1, osc+2*%[mul]+%[pha]+1" "\n\t" \
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"adc r1, r18 " "\n\t" \
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"sts osc+2*%[mul]+%[pha]+1, r1 " "\n\t" \
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\
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"mov r27, r1 " "\n\t" \
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"sbrc r27, 7 " "\n\t" \
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"com r27 " "\n\t" \
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"lsl r27 " "\n\t" \
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"lds r26, osc+2*%[mul]+%[vol] " "\n\t" \
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"subi r27, 128 " "\n\t" \
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"muls r27, r26 " "\n\t" \
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"lsl r1 " "\n\t" \
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"mov r26, r1 " "\n\t" \
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\
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"lds r18, osc+0*%[mul]+%[fre] " "\n\t" \
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"lds r0, osc+0*%[mul]+%[pha] " "\n\t" \
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"add r0, r18 " "\n\t" \
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"sts osc+0*%[mul]+%[pha], r0 " "\n\t" \
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"lds r18, osc+0*%[mul]+%[fre]+1" "\n\t" \
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"lds r1, osc+0*%[mul]+%[pha]+1" "\n\t" \
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"adc r1, r18 " "\n\t" \
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"sts osc+0*%[mul]+%[pha]+1, r1 " "\n\t" \
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\
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"mov r18, r1 " "\n\t" \
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"lsl r18 " "\n\t" \
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"and r18, r1 " "\n\t" \
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"lds r27, osc+0*%[mul]+%[vol] " "\n\t" \
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"sbrc r18, 7 " "\n\t" \
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"neg r27 " "\n\t" \
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"add r26, r27 " "\n\t" \
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\
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"lds r18, osc+1*%[mul]+%[fre] " "\n\t" \
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"lds r0, osc+1*%[mul]+%[pha] " "\n\t" \
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"add r0, r18 " "\n\t" \
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"sts osc+1*%[mul]+%[pha], r0 " "\n\t" \
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"lds r18, osc+1*%[mul]+%[fre]+1" "\n\t" \
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"lds r1, osc+1*%[mul]+%[pha]+1" "\n\t" \
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"adc r1, r18 " "\n\t" \
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"sts osc+1*%[mul]+%[pha]+1, r1 " "\n\t" \
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\
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"lds r27, osc+1*%[mul]+%[vol] " "\n\t" \
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"sbrc r1, 7 " "\n\t" \
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"neg r27 " "\n\t" \
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"add r26, r27 " "\n\t" \
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\
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"ldi r27, 1 " "\n\t" \
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"lds r0, osc+3*%[mul]+%[fre] " "\n\t" \
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"lds r1, osc+3*%[mul]+%[fre]+1" "\n\t" \
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"add r0, r0 " "\n\t" \
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"adc r1, r1 " "\n\t" \
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"sbrc r1, 7 " "\n\t" \
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"eor r0, r27 " "\n\t" \
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"sbrc r1, 6 " "\n\t" \
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"eor r0, r27 " "\n\t" \
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"sts osc+3*%[mul]+%[fre], r0 " "\n\t" \
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"sts osc+3*%[mul]+%[fre]+1, r1 " "\n\t" \
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\
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"lds r27, osc+3*%[mul]+%[vol] " "\n\t" \
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"sbrc r1, 7 " "\n\t" \
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"neg r27 " "\n\t" \
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"add r26, r27 " "\n\t" \
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\
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"lds r27, pcm " "\n\t" \
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"add r26, r27 " "\n\t" \
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"sts %[reg], r26 " "\n\t" \
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\
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"lds r27, cia_count+1 " "\n\t" \
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"lds r26, cia_count " "\n\t" \
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"sbiw r26, 1 " "\n\t" \
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"breq call_playroutine " "\n\t" \
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"sts cia_count+1, r27 " "\n\t" \
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"sts cia_count, r26 " "\n\t" \
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"pop r1 " "\n\t" \
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"pop r0 " "\n\t" \
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"pop r26 " "\n\t" \
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"pop r27 " "\n\t" \
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"pop r18 " "\n\t" \
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"out __SREG__, r2 " "\n\t" \
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"pop r2 " "\n\t" \
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"reti " "\n\t" \
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"call_playroutine: " "\n\t" \
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\
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"lds r27, cia+1 " "\n\t" \
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"lds r26, cia " "\n\t" \
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"sts cia_count+1, r27 " "\n\t" \
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"sts cia_count, r26 " "\n\t" \
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\
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"sei " "\n\t" \
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"push r19 " "\n\t" \
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"push r20 " "\n\t" \
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"push r21 " "\n\t" \
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"push r22 " "\n\t" \
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"push r23 " "\n\t" \
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"push r24 " "\n\t" \
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"push r25 " "\n\t" \
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"push r30 " "\n\t" \
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"push r31 " "\n\t" \
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\
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"clr r1 " "\n\t" \
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"call squawk_playroutine " "\n\t" \
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\
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"pop r31 " "\n\t" \
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"pop r30 " "\n\t" \
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"pop r25 " "\n\t" \
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"pop r24 " "\n\t" \
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"pop r23 " "\n\t" \
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"pop r22 " "\n\t" \
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"pop r21 " "\n\t" \
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"pop r20 " "\n\t" \
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"pop r19 " "\n\t" \
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\
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"pop r1 " "\n\t" \
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"pop r0 " "\n\t" \
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"pop r26 " "\n\t" \
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"pop r27 " "\n\t" \
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"pop r18 " "\n\t" \
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"out __SREG__, r2 " "\n\t" \
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"pop r2 " "\n\t" \
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"reti " "\n\t" \
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: \
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: [reg] "M" _SFR_MEM_ADDR(TARGET_REGISTER), \
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[mul] "M" (sizeof(Oscillator)), \
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[pha] "M" (offsetof(Oscillator, phase)), \
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[fre] "M" (offsetof(Oscillator, freq)), \
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[vol] "M" (offsetof(Oscillator, vol)) \
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); \
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}
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#endif |