mirror of https://github.com/bsnes-emu/bsnes.git
63 lines
1.5 KiB
C++
Executable File
63 lines
1.5 KiB
C++
Executable File
#ifdef DSP_CPP
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void DSP::envelope_run(voice_t &v) {
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int env = v.env;
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if(v.env_mode == env_release) { //60%
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env -= 0x8;
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if(env < 0) env = 0;
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v.env = env;
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return;
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}
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int rate;
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int env_data = VREG(adsr1);
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if(state.t_adsr0 & 0x80) { //99% ADSR
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if(v.env_mode >= env_decay) { //99%
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env--;
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env -= env >> 8;
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rate = env_data & 0x1f;
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if(v.env_mode == env_decay) { //1%
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rate = ((state.t_adsr0 >> 3) & 0x0e) + 0x10;
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}
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} else { //env_attack
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rate = ((state.t_adsr0 & 0x0f) << 1) + 1;
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env += rate < 31 ? 0x20 : 0x400;
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}
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} else { //GAIN
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env_data = VREG(gain);
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int mode = env_data >> 5;
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if(mode < 4) { //direct
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env = env_data << 4;
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rate = 31;
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} else {
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rate = env_data & 0x1f;
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if(mode == 4) { //4: linear decrease
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env -= 0x20;
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} else if(mode < 6) { //5: exponential decrease
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env--;
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env -= env >> 8;
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} else { //6, 7: linear increase
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env += 0x20;
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if(mode > 6 && (unsigned)v.hidden_env >= 0x600) {
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env += 0x8 - 0x20; //7: two-slope linear increase
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}
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}
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}
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}
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//sustain level
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if((env >> 8) == (env_data >> 5) && v.env_mode == env_decay) v.env_mode = env_sustain;
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v.hidden_env = env;
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//unsigned cast because linear decrease underflowing also triggers this
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if((unsigned)env > 0x7ff) {
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env = (env < 0 ? 0 : 0x7ff);
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if(v.env_mode == env_attack) v.env_mode = env_decay;
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}
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if(counter_poll(rate) == true) v.env = env;
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}
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#endif
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