116 lines
2.6 KiB
C++
116 lines
2.6 KiB
C++
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#include "voice.hpp"
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#include <cmath>
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bool Voice::isFree() {
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return ff10 == false;
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}
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void Voice::on(uint32_t key, bool reset = 0) {
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// printf("======================================================================================\n");
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// what's with the crazy private variables and all the gotos with crazy labels?
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// this code emulates the 78C11 code directly (probably inefficiently)
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// to allow for documenting what the variables actually do
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// they're really bitfields holding a bit for each voice
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// this current implementation doesn't reset the voice
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(void)reset;
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ff10 = true; // note held from keyboard
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ff07 = true; // attack phase
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if (note == key) goto h0144;
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note = key;
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if (ff11) goto h013e;
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h0132:
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if (ff33) goto h0149; // sustained
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ff33 = false;
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goto h0149;
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h013e:
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ff00 = true; // in a real one, voice counter needs programmed
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goto h0149;
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h0144:
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if (!ff11) goto h0132; // unsure, copied from ff10 at start of mainloop
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h0149:
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// printf("after 0144h, %d %x %x %x %x\n", note, ff07, ff10, ff11, ff33);
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// this is in the wrong place really but is the equivalent of programming the counter
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// and VCO ramp DAC
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omega = (261.63 * powf(2, (note - 60) / 12.0f)) / 48000.0f;
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}
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void Voice::off() {
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bool sustain = false;
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ff10 = false;
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if (!sustain) { // dummy sustain
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ff33 = false;
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}
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// printf("after note off, %d %x %x %x %x\n", note, ff07, ff10, ff11, ff33);
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}
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void Voice::gate(Synth &s) {
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uint16_t bc, ea = env;
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ff11 = ff10;
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// 0509
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if (!ff11) goto h0538;
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// 050e
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if (!ff33) goto h0563;
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// 0513
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if (!ff07) goto h051e;
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h0517:
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ff07 = false;
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h051e:
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bc = s.patchRam.env_s << 7; // half scale
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if (ea < bc) ea = bc;
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ea -= bc;
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bc = ea;
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ea = (ea * decay_table[s.patchRam.env_d]) >> 16;
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ea += s.patchRam.env_s << 7;
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// printf("returning from decay phase\n");
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goto h0590;
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h0538:
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// printf("got to 0x0538\n");
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if (!ff07) goto h054a; // note on? if not skip ahead
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// 053c
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if (ff08) goto h0517;
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ff07 = false;
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h054a:
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// printf("release phase\n");
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ff33 = false;
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ff08 = false;
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bc = ea;
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ea = (ea * decay_table[s.patchRam.env_r]) >> 16;
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// printf("returning from release phase\n");
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goto h0590;
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h0563:
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// printf("attack phase\n");
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ff08 = false;
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ea += attack_table[s.patchRam.env_a];
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if (ea & 0xc000) {
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ea = 0x3fff;
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ff33 = true;
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ff08 = true;
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}
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h0590:
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env = ea;
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// printf("%04x %d %d %d %d %d \n", ea, ff07, ff08, ff10, ff11, ff33);
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}
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