mirror of
https://github.com/vsariola/sointu.git
synced 2025-05-28 03:10:24 -04:00
01bf409929
The commands and values were not very good names to what the byte sequences actually are: opcodes and their operands. In many other places, we were already calling the byte in the Command stream as Opcode, so a logical name for a sequence of these is Opcodes. Values is such a generic name that it's not immediately clear that this sequence is related to the opcodes. Operands is not perfect but clearly suggests that this sequence is related to the Opcodes.
628 lines
17 KiB
Go
628 lines
17 KiB
Go
package vm
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"math"
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"os"
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"path/filepath"
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"github.com/vsariola/sointu"
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)
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//go:generate go run generate/generate.go
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// GoSynth is a pure-Go bytecode interpreter for the Sointu VM bytecode. It
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// can only simulate bytecode compiled for AllFeatures, as the opcodes hard
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// coded in it for speed. If you are interested exactly how opcodes / units
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// work, studying GoSynth.Render is a good place to start.
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//
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// Internally, it uses software stack with practically no limitations in the
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// number of signals, so be warned that if you compose patches for it, they
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// might not work with the x87 implementation, as it has only 8-level stack.
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type GoSynth struct {
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bytecode Bytecode
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stack []float32
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synth synth
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delaylines []delayline
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}
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type GoSynther struct {
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}
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const MAX_VOICES = 32
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const MAX_UNITS = 63
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type unit struct {
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state [8]float32
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ports [8]float32
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}
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type voice struct {
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note byte
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sustain bool
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units [MAX_UNITS]unit
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}
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type synth struct {
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outputs [8]float32
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randSeed uint32
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globalTime uint32
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voices [MAX_VOICES]voice
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}
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type delayline struct {
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buffer [65536]float32
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dampState float32
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dcIn float32
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dcFiltState float32
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}
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const (
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envStateAttack = iota
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envStateDecay
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envStateSustain
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envStateRelease
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)
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var su_sample_table [3440660]byte
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func init() {
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var f *os.File
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var err error
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if f, err = os.Open("gm.dls"); err == nil { // try to open from current directory first
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goto success
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}
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if f, err = os.Open(filepath.Join(os.Getenv("SystemRoot"), "system32", "drivers", "gm.dls")); err == nil {
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goto success
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}
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if f, err = os.Open(filepath.Join(os.Getenv("SystemRoot"), "SysWOW64", "drivers", "gm.dls")); err == nil {
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goto success
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}
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return
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success:
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defer f.Close()
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// read file, ignoring errors
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f.Read(su_sample_table[:])
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}
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func Synth(patch sointu.Patch, bpm int) (sointu.Synth, error) {
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bytecode, err := Encode(patch, AllFeatures{}, bpm)
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if err != nil {
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return nil, fmt.Errorf("error compiling %v", err)
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}
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ret := &GoSynth{bytecode: *bytecode, stack: make([]float32, 0, 4), delaylines: make([]delayline, patch.NumDelayLines())}
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ret.synth.randSeed = 1
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return ret, nil
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}
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func (s GoSynther) Synth(patch sointu.Patch, bpm int) (sointu.Synth, error) {
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synth, err := Synth(patch, bpm)
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return synth, err
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}
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func (s *GoSynth) Trigger(voiceIndex int, note byte) {
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s.synth.voices[voiceIndex] = voice{}
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s.synth.voices[voiceIndex].note = note
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s.synth.voices[voiceIndex].sustain = true
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}
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func (s *GoSynth) Release(voiceIndex int) {
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s.synth.voices[voiceIndex].sustain = false
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}
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func (s *GoSynth) Update(patch sointu.Patch, bpm int) error {
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bytecode, err := Encode(patch, AllFeatures{}, bpm)
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if err != nil {
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return fmt.Errorf("error compiling %v", err)
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}
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needsRefresh := len(bytecode.Opcodes) != len(s.bytecode.Opcodes)
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if !needsRefresh {
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for i, c := range bytecode.Opcodes {
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if s.bytecode.Opcodes[i] != c {
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needsRefresh = true
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break
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}
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}
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}
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s.bytecode = *bytecode
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for len(s.delaylines) < patch.NumDelayLines() {
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s.delaylines = append(s.delaylines, delayline{})
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}
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if needsRefresh {
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for i := range s.synth.voices {
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for j := range s.synth.voices[i].units {
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s.synth.voices[i].units[j] = unit{}
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}
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}
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}
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return nil
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}
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func (s *GoSynth) Render(buffer sointu.AudioBuffer, maxtime int) (samples int, time int, renderError error) {
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defer func() {
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if err := recover(); err != nil {
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renderError = fmt.Errorf("render panicced: %v", err)
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}
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}()
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var params [8]float32
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stack := s.stack[:]
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stack = append(stack, []float32{0, 0, 0, 0}...)
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synth := &s.synth
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for time < maxtime && len(buffer) > 0 {
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opcodesInstr := s.bytecode.Opcodes
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operandsInstr := s.bytecode.Operands
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opcodes, operands := opcodesInstr, operandsInstr
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delaylines := s.delaylines
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voicesRemaining := s.bytecode.NumVoices
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voices := s.synth.voices[:]
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units := voices[0].units[:]
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for voicesRemaining > 0 {
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op := opcodes[0]
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opcodes = opcodes[1:]
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channels := int((op & 1) + 1)
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stereo := channels == 2
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opNoStereo := (op & 0xFE) >> 1
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if opNoStereo == 0 {
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voicesRemaining--
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if voicesRemaining > 0 {
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voices = voices[1:]
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units = voices[0].units[:]
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}
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if mask := uint32(1) << uint32(voicesRemaining); s.bytecode.PolyphonyBitmask&mask == mask {
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opcodes, operands = opcodesInstr, operandsInstr
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} else {
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opcodesInstr, operandsInstr = opcodes, operands
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}
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continue
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}
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tcount := transformCounts[opNoStereo-1]
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if len(operands) < tcount {
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return samples, time, errors.New("operand stream ended prematurely")
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}
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voice := &voices[0]
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unit := &units[0]
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operandsAtTransform := operands
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for i := 0; i < tcount; i++ {
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params[i] = float32(operands[0])/128.0 + unit.ports[i]
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unit.ports[i] = 0
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operands = operands[1:]
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}
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l := len(stack)
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switch opNoStereo {
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case opAdd:
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if stereo {
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stack[l-1] += stack[l-3]
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stack[l-2] += stack[l-4]
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} else {
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stack[l-1] += stack[l-2]
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}
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case opAddp:
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if stereo {
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stack[l-3] += stack[l-1]
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stack[l-4] += stack[l-2]
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stack = stack[:l-2]
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} else {
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stack[l-2] += stack[l-1]
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stack = stack[:l-1]
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}
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case opMul:
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if stereo {
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stack[l-1] *= stack[l-3]
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stack[l-2] *= stack[l-4]
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} else {
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stack[l-1] *= stack[l-2]
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}
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case opMulp:
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if stereo {
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stack[l-3] *= stack[l-1]
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stack[l-4] *= stack[l-2]
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stack = stack[:l-2]
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} else {
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stack[l-2] *= stack[l-1]
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stack = stack[:l-1]
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}
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case opXch:
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if stereo {
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stack[l-3], stack[l-1] = stack[l-1], stack[l-3]
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stack[l-4], stack[l-2] = stack[l-2], stack[l-4]
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} else {
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stack[l-2], stack[l-1] = stack[l-1], stack[l-2]
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}
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case opPush:
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if stereo {
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stack = append(stack, stack[l-2])
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}
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stack = append(stack, stack[l-1])
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case opPop:
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if stereo {
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stack = stack[:l-2]
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} else {
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stack = stack[:l-1]
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}
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case opDistort:
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amount := params[0]
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if stereo {
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stack[l-2] = waveshape(stack[l-2], amount)
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}
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stack[l-1] = waveshape(stack[l-1], amount)
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case opLoadval:
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val := params[0]*2 - 1
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if stereo {
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stack = append(stack, val)
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}
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stack = append(stack, val)
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case opOut:
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if stereo {
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synth.outputs[0] += params[0] * stack[l-1]
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synth.outputs[1] += params[0] * stack[l-2]
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stack = stack[:l-2]
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} else {
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synth.outputs[0] += params[0] * stack[l-1]
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stack = stack[:l-1]
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}
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case opOutaux:
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if stereo {
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synth.outputs[0] += params[0] * stack[l-1]
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synth.outputs[1] += params[0] * stack[l-2]
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synth.outputs[2] += params[1] * stack[l-1]
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synth.outputs[3] += params[1] * stack[l-2]
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stack = stack[:l-2]
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} else {
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synth.outputs[0] += params[0] * stack[l-1]
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synth.outputs[2] += params[1] * stack[l-1]
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stack = stack[:l-1]
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}
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case opAux:
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var channel byte
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channel, operands = operands[0], operands[1:]
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if stereo {
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synth.outputs[channel+1] += params[0] * stack[l-2]
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}
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synth.outputs[channel] += params[0] * stack[l-1]
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stack = stack[:l-channels]
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case opSpeed:
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r := unit.state[0] + float32(math.Exp2(float64(stack[l-1]*2.206896551724138))-1)
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w := int(r+1.5) - 1
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unit.state[0] = r - float32(w)
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time += w
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stack = stack[:l-1]
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case opIn:
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var channel byte
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channel, operands = operands[0], operands[1:]
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if stereo {
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stack = append(stack, synth.outputs[channel+1])
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synth.outputs[channel+1] = 0
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}
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stack = append(stack, synth.outputs[channel])
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synth.outputs[channel] = 0
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case opEnvelope:
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if !voices[0].sustain {
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unit.state[0] = envStateRelease // set state to release
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}
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state := unit.state[0]
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level := unit.state[1]
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switch state {
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case envStateAttack:
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level += nonLinearMap(params[0])
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if level >= 1 {
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level = 1
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state = envStateDecay
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}
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case envStateDecay:
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level -= nonLinearMap(params[1])
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if sustain := params[2]; level <= sustain {
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level = sustain
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}
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case envStateRelease:
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level -= nonLinearMap(params[3])
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if level <= 0 {
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level = 0
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}
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}
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unit.state[0] = state
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unit.state[1] = level
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output := level * params[4]
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stack = append(stack, output)
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if stereo {
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stack = append(stack, output)
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}
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case opNoise:
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if stereo {
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value := waveshape(synth.rand(), params[0]) * params[1]
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stack = append(stack, value)
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}
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value := waveshape(synth.rand(), params[0]) * params[1]
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stack = append(stack, value)
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case opGain:
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if stereo {
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stack[l-2] *= params[0]
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}
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stack[l-1] *= params[0]
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case opInvgain:
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if stereo {
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stack[l-2] /= params[0]
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}
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stack[l-1] /= params[0]
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case opClip:
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if stereo {
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stack[l-2] = clip(stack[l-2])
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}
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stack[l-1] = clip(stack[l-1])
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case opCrush:
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if stereo {
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stack[l-2] = crush(stack[l-2], params[0])
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}
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stack[l-1] = crush(stack[l-1], params[0])
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case opHold:
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freq2 := params[0] * params[0]
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for i := 0; i < channels; i++ {
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phase := unit.state[i] - freq2
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if phase <= 0 {
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unit.state[2+i] = stack[l-1-i]
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phase += 1.0
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}
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stack[l-1-i] = unit.state[2+i]
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unit.state[i] = phase
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}
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case opSend:
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var addrLow, addrHigh byte
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addrLow, addrHigh, operands = operands[0], operands[1], operands[2:]
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addr := (uint16(addrHigh) << 8) + uint16(addrLow)
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targetVoice := voice
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if addr&0x8000 == 0x8000 {
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addr -= 0x8010
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targetVoice = &synth.voices[addr>>10]
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}
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unitIndex := ((addr & 0x01F0) >> 4) - 1
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port := addr & 7
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amount := params[0]*2 - 1
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for i := 0; i < channels; i++ {
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targetVoice.units[unitIndex].ports[int(port)+i] += stack[l-1-i] * amount
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}
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if addr&0x8 == 0x8 {
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stack = stack[:l-channels]
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}
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case opReceive:
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if stereo {
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stack = append(stack, unit.ports[1])
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unit.ports[1] = 0
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}
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stack = append(stack, unit.ports[0])
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unit.ports[0] = 0
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case opLoadnote:
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noteFloat := float32(voice.note)/64 - 1
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stack = append(stack, noteFloat)
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if stereo {
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stack = append(stack, noteFloat)
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}
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case opPan:
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if !stereo {
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stack = append(stack, stack[l-1])
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l++
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}
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stack[l-2] *= params[0]
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stack[l-1] *= 1 - params[0]
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case opFilter:
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freq2 := params[0] * params[0]
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res := params[1]
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var flags byte
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flags, operands = operands[0], operands[1:]
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for i := 0; i < channels; i++ {
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low, band := unit.state[0+i], unit.state[2+i]
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low += freq2 * band
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high := stack[l-1-i] - low - res*band
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band += freq2 * high
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unit.state[0+i], unit.state[2+i] = low, band
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var output float32
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if flags&0x40 == 0x40 {
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output += low
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}
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if flags&0x20 == 0x20 {
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output += band
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}
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if flags&0x10 == 0x10 {
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output += high
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}
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if flags&0x08 == 0x08 {
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output -= band
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}
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if flags&0x04 == 0x04 {
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output -= high
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}
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stack[l-1-i] = output
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}
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case opOscillator:
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var flags byte
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flags, operands = operands[0], operands[1:]
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detuneStereo := params[1]*2 - 1
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unison := flags & 3
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for i := 0; i < channels; i++ {
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detune := detuneStereo
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var output float32
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for j := byte(0); j <= unison; j++ {
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statevar := &unit.state[byte(i)+j*2]
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pitch := float64(64*(params[0]*2-1) + detune)
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if flags&0x8 == 0 { // if lfo is disable, add note to oscillator transpose
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pitch += float64(voice.note)
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}
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pitch *= 0.083333333333 // from semitones to octaves
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omega := math.Exp2(pitch)
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if flags&0x8 == 0 {
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omega *= 0.000092696138 // scaling coefficient to get middle-C where it should be
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} else {
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omega *= 0.000038 // pretty random scaling constant to get LFOs into reasonable range. Historical reasons, goes all the way back to 4klang
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}
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omega += float64(unit.ports[6]) // add frequency modulation
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var amplitude float32
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*statevar += float32(omega)
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if flags&0x80 == 0x80 { // if this is a sample oscillator
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phase := *statevar
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phase += params[2]
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sampleno := operandsAtTransform[3] // reuse color as the sample number
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sampleoffset := s.bytecode.SampleOffsets[sampleno]
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sampleindex := int(phase*84.28074964676522 + 0.5)
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loopstart := int(sampleoffset.LoopStart)
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if sampleindex >= loopstart {
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sampleindex -= loopstart
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sampleindex %= int(sampleoffset.LoopLength)
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sampleindex += loopstart
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}
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sampleindex += int(sampleoffset.Start)
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amplitude = float32(int16(binary.LittleEndian.Uint16(su_sample_table[sampleindex*2:]))) / 32767.0
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} else {
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*statevar -= float32(int(*statevar+1) - 1)
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phase := *statevar
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phase += params[2]
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phase -= float32(int(phase))
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color := params[3]
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switch {
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case flags&0x40 == 0x40: // Sine
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if phase < color {
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amplitude = float32(math.Sin(2 * math.Pi * float64(phase/color)))
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}
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case flags&0x20 == 0x20: // Trisaw
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if phase >= color {
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phase = 1 - phase
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color = 1 - color
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}
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amplitude = phase/color*2 - 1
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case flags&0x10 == 0x10: // Pulse
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if phase >= color {
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amplitude = -1
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} else {
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amplitude = 1
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}
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case flags&0x4 == 0x4: // Gate
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maskLow, maskHigh := operandsAtTransform[3], operandsAtTransform[4]
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gateBits := (int(maskHigh) << 8) + int(maskLow)
|
|
amplitude = float32((gateBits >> (int(phase*16+.5) & 15)) & 1)
|
|
g := unit.state[4+i] // warning: still fucks up with unison = 3
|
|
amplitude += 0.99609375 * (g - amplitude)
|
|
unit.state[4+i] = amplitude
|
|
}
|
|
}
|
|
if flags&0x4 == 0 {
|
|
output += waveshape(amplitude, params[4]) * params[5]
|
|
} else {
|
|
output += amplitude * params[5]
|
|
}
|
|
if j < unison {
|
|
params[2] += 0.08333333 // 1/12, add small phase shift so all oscillators don't start in phase
|
|
}
|
|
detune = -detune * 0.5
|
|
}
|
|
stack = append(stack, output)
|
|
detuneStereo = -detuneStereo
|
|
}
|
|
unit.ports[6] = 0
|
|
case opDelay:
|
|
pregain2 := params[0] * params[0]
|
|
damp := params[3]
|
|
feedback := params[2]
|
|
var index, count byte
|
|
index, count, operands = operands[0], operands[1], operands[2:]
|
|
t := uint16(s.synth.globalTime)
|
|
stackIndex := l - channels
|
|
for i := 0; i < channels; i++ {
|
|
var d *delayline
|
|
signal := stack[stackIndex]
|
|
output := params[1] * signal // dry output
|
|
for j := byte(0); j < count; j += 2 {
|
|
d, delaylines = &delaylines[0], delaylines[1:]
|
|
delay := float32(s.bytecode.DelayTimes[index]) + unit.ports[4]*32767
|
|
if count&1 == 0 {
|
|
delay /= float32(math.Exp2(float64(voice.note) * 0.083333333333))
|
|
}
|
|
delSignal := d.buffer[t-uint16(delay+0.5)]
|
|
output += delSignal
|
|
d.dampState = damp*d.dampState + (1-damp)*delSignal
|
|
d.buffer[t] = feedback*d.dampState + pregain2*signal
|
|
index++
|
|
}
|
|
d.dcFiltState = output + (0.99609375*d.dcFiltState - d.dcIn)
|
|
d.dcIn = output
|
|
stack[stackIndex] = d.dcFiltState
|
|
stackIndex++
|
|
}
|
|
unit.ports[4] = 0
|
|
case opCompressor:
|
|
signalLevel := stack[l-1] * stack[l-1] // square the signal to get power
|
|
if stereo {
|
|
signalLevel += stack[l-2] * stack[l-2]
|
|
}
|
|
currentLevel := unit.state[0]
|
|
paramIndex := 0 // compressor attacking
|
|
if signalLevel < currentLevel {
|
|
paramIndex = 1 // compressor releasing
|
|
}
|
|
alpha := nonLinearMap(params[paramIndex]) // map attack or release to a smoothing coefficient
|
|
currentLevel += (signalLevel - currentLevel) * alpha
|
|
unit.state[0] = currentLevel
|
|
var gain float32 = 1
|
|
if threshold2 := params[3] * params[3]; currentLevel > threshold2 {
|
|
gain = float32(math.Pow(float64(threshold2/currentLevel), float64(params[4]/2)))
|
|
}
|
|
gain /= params[2] // apply inverse gain
|
|
stack = append(stack, gain)
|
|
if stereo {
|
|
stack = append(stack, gain)
|
|
}
|
|
case opSync:
|
|
break
|
|
default:
|
|
return samples, time, errors.New("invalid / unimplemented opcode")
|
|
}
|
|
units = units[1:]
|
|
}
|
|
if len(stack) < 4 {
|
|
return samples, time, errors.New("stack underflow")
|
|
}
|
|
if len(stack) > 4 {
|
|
return samples, time, errors.New("stack not empty")
|
|
}
|
|
buffer[0][0], buffer[0][1] = synth.outputs[0], synth.outputs[1]
|
|
synth.outputs[0] = 0
|
|
synth.outputs[1] = 0
|
|
buffer = buffer[1:]
|
|
samples++
|
|
time++
|
|
s.synth.globalTime++
|
|
}
|
|
s.stack = stack[:0]
|
|
return samples, time, nil
|
|
}
|
|
|
|
func (s *synth) rand() float32 {
|
|
s.randSeed *= 16007
|
|
return float32(int32(s.randSeed)) / -2147483648.0
|
|
}
|
|
|
|
func nonLinearMap(value float32) float32 {
|
|
return float32(math.Exp2(float64(-24 * value)))
|
|
}
|
|
|
|
func clip(value float32) float32 {
|
|
if value < -1 {
|
|
return -1
|
|
}
|
|
if value > 1 {
|
|
return 1
|
|
}
|
|
return value
|
|
}
|
|
|
|
func crush(value, amount float32) float32 {
|
|
n := nonLinearMap(amount)
|
|
return float32(math.Round(float64(value/n)) * float64(n))
|
|
}
|
|
|
|
func waveshape(value, amount float32) float32 {
|
|
absVal := value
|
|
if absVal < 0 {
|
|
absVal = -absVal
|
|
}
|
|
return value * amount / (1 - amount + (2*amount-1)*absVal)
|
|
}
|