Include my code

.gitignore

@@ -0,0 +1,3 @@
+/target
+example.wav
+.vscode/

Cargo.lock

@@ -0,0 +1,25 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "lansky"
+version = "0.1.0"
+dependencies = [
+ "wav",
+]
+
+[[package]]
+name = "riff"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b9b1a3d5f46d53f4a3478e2be4a5a5ce5108ea58b100dcd139830eae7f79a3a1"
+
+[[package]]
+name = "wav"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a65e199c799848b4f997072aa4d673c034f80f40191f97fe2f0a23f410be1609"
+dependencies = [
+ "riff",
+]

Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "lansky"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+wav = "1.0.0"

asm_notes.txt

@@ -0,0 +1,77 @@
+NOTES: Slightly out of date -- I haven't added the Imm mov mode or the ix register yet
+
+Registers:
+    $a0..9: Corresponds to input 0 through 9
+    $l0..9: "Locals" 0..9
+    $z0..9: Corresponds to output 0 through 9
+    $r0..255: Auxiliary uint64_ts
+
+    $ix: Index base
+
+Channels:
+    A channel is a vector of samples with a known "formal range" --
+    this formal range includes its start (relative to the whole song)
+    and its basic length.
+
+    You can use outputs that aren't exposed as part of your device. 
+    This can be a good place to hide wavetables and stuff.
+    They just won't be returned.
+
+Memory model:
+    $a0..9, $l0..9, and $z0..9 correspond to arrays
+    When you read $a0, it reads channel a0 at $ix+a0.formal_start+a0.loop_start
+    When you write $z0, it writes channel z0 at $ix+z0.formal_start+z0.loop_start
+
+    Unknown positions are 0.
+
+    A channel has an informal_start and an informal_length which initially match
+    formal_start and formal_length.
+
+    Writing to a position outside of informal_start..informal_start+informal_length 
+    extends the bounds.
+
+    In looped mode, then the ultimate indices are wrapped to 
+    (formal_start+loop_start..formal_start+loop_start+loop_length) 
+    and all other behavior remains the same as above.
+
+Instructions:
+    mov|add|xor ($l0..9, $z0..9, $r0..255), ($a0..9, $l0..9, $z0..9, $r0..255)
+    Copy value, add value, or xor value.
+
+    range ($a0..9, $l0..9, $z0..9), loop_start, loop_length
+    Start and length are immediate values.
+    If length is nonzero, the channel is in "looped" mode. 
+
+    inp ($a0..9, $l0..9, $z0..9)
+    Push a copy of the channel to the stack for "invoke".
+    The channel will be sliced:
+    - if loop_start is zero and loop_length is zero: 
+        The formal range runs from formal_start to formal_start+formal_length.
+        The informal range runs from informal_start to informal_start+informal_length.
+    - if loop_start is nonzero and loop_length is zero: 
+        The formal range runs from formal_start+loop_start to formal_start+formal_length
+        The informal range runs from formal_start+loop_start to informal_start+informal_length
+    - if loop_length is nonzero: 
+        The formal range runs from formal_start+loop_start to formal_start+loop_start+loop_length
+        The informal range is the same as the formal range.
+
+    dup
+    Duplicate an item from the invoke stack.
+
+    oup (mov|add|xor) ($l0..9, $z0..9)
+    Pop an output from the invoke stack and write it to an output channel or local.
+
+    All indexes from informal_start to informal_start+informal_length are written.
+
+    The instruction used to write can be mov, add, or xor
+
+    invoke device, n_inputs, n_outputs
+    Invoke the device by name (an immediate string)
+    Asserts that the device takes n_inputs inputs (an immediate integer) and n_outputs outputs (an immediate integer)
+    Asserts that there are actually n_inputs inputs on the stack.
+    After invoke, there will be n_outputs outputs on the stack.
+    They will be ordered such that the first call to oup produces the first output, the second produces the second, 
+    and so on
+
+    exit
+    Exit the current procedure.

src/audio.rs

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+use std::ops::{Range, Index, IndexMut};
+
+// Fixed point: 0xFFFF_FFFF.FFFF_FFFF
+#[derive(Clone, Copy)]
+pub struct Sample(pub i64);
+
+impl Sample {
+    pub fn to_i16_sample(&self) -> i16 {
+        // interpret self as fixed-point
+        if self.0 > i32::MAX as i64 { return i16::MAX }
+        if self.0 < i32::MIN as i64 { return i16::MIN }
+        let low_part = self.0 as i32;
+        return (low_part >> 16) as i16
+    }
+}
+
+impl Default for Sample {
+    fn default() -> Self { BLANK_SAMPLE }
+}
+
+const BLANK_SAMPLE: Sample = Sample(0);
+
+#[derive(Clone)]
+pub struct Channel {
+    formal: Range<i32>,
+
+    minus: Vec<Sample>,
+    plus: Vec<Sample>,
+}
+
+pub struct Bounds {
+    pub formal: Range<i32>,
+    pub informal: Range<i32>,
+}
+
+impl Channel {
+    pub fn new(formal: Range<i32>) -> Self {
+        assert!(formal.end >= formal.start);
+        Channel {
+            formal: formal,
+            minus: vec![],
+            plus: vec![],
+        }
+    }
+
+    pub fn formal(&self) -> Range<i32> {
+        self.formal.clone()
+    }
+
+    pub fn bounds(&self) -> Bounds {
+        let formal = self.formal.clone();
+        let informal_start = formal.start - self.minus.len() as i32;
+        let informal_len_0 = self.minus.len() + self.plus.len();
+        let informal_len_1 = (formal.end - informal_start) as usize; 
+        let informal_len = informal_len_0.max(informal_len_1);
+
+        return Bounds {
+            formal,
+            informal: informal_start..(informal_start + informal_len as i32)
+        }
+    }
+
+    pub(crate) fn blank() -> Channel {
+        return Channel::new(0..0);
+    }
+
+    pub fn slice(&self, start: i32, length: i32) -> Channel {
+        if start == 0 && length == 0 {
+            return self.clone()
+        }
+        if start != 0 && length == 0 {
+            let formal_start = self.formal.start + start;
+            let mut formal_end = self.formal.start + self.formal.end;
+            if formal_end < formal_start { formal_end = formal_start; }
+
+            let mut chan = Channel::new(formal_start..formal_end);
+            for i in 0..self.plus.len() {
+                chan[self.formal.start + i as i32] = self[self.formal.start + i as i32]
+            }
+            return chan
+        }
+
+        let formal_start = self.formal.start + start;
+        let formal_end = self.formal.start + start + length;
+        let mut chan = Channel::new(formal_start..formal_end);
+        for i in formal_start..formal_end {
+            chan[i] = self[i];
+        }
+        return chan
+    }
+} 
+
+impl Index<i32> for Channel {
+    type Output = Sample;
+
+    fn index(&self, index: i32) -> &Self::Output {
+        let adj_idx = index - self.formal.start;
+        if adj_idx < 0 {
+            let neg_adj_idx = (-adj_idx) as usize - 1;
+            self.minus.get(neg_adj_idx).unwrap_or(&BLANK_SAMPLE)
+        } else {
+            let pos_adj_idx = adj_idx as usize;
+            self.plus.get(pos_adj_idx).unwrap_or(&BLANK_SAMPLE)
+        }
+    }
+}
+
+impl IndexMut<i32> for Channel {
+    fn index_mut(&mut self, index: i32) -> &mut Self::Output {
+        let adj_idx = index - self.formal.start;
+        if adj_idx < 0 {
+            let neg_adj_idx = (-adj_idx) as usize - 1;
+            if self.minus.len() < neg_adj_idx + 1 {
+                self.minus.reserve(neg_adj_idx + 1);
+                while self.minus.len() < neg_adj_idx + 1 {
+                    self.minus.push(BLANK_SAMPLE);
+                }
+            }
+            return &mut self.minus[neg_adj_idx]
+        } else {
+            let pos_adj_idx = adj_idx as usize;
+            if self.plus.len() < pos_adj_idx + 1{
+                self.plus.reserve(pos_adj_idx + 1);
+                while self.plus.len() < pos_adj_idx + 1 {
+                    self.plus.push(BLANK_SAMPLE);
+                }
+            }
+            return &mut self.plus[pos_adj_idx]
+        }
+    }
+}

src/device.rs

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+use std::{collections::HashMap, cell::Cell};
+
+use crate::{audio::Channel, error::{Lansky, LanskyError}, vm::{Procedure, Block}, rack::Rack};
+
+pub struct Device {
+    proto: Proto,
+    implementation: Implementation,
+}
+
+#[derive(Clone)]
+pub struct Proto {  
+    pub name: String,
+    pub inputs: Vec<String>,
+    pub outputs: Vec<String>,
+}
+
+
+enum Implementation {
+    Native(fn(Vec<Channel>) -> Lansky<Vec<Channel>>),
+    Hosted(Procedure),
+}
+
+impl Device {
+    pub fn native(
+        name: String, 
+        inputs: Vec<String>, 
+        outputs: Vec<String>, 
+        native: fn(Vec<Channel>) -> Lansky<Vec<Channel>>
+    ) -> Lansky<Self> {
+        let proto = Proto { name, inputs, outputs };
+        Self::new(proto, Implementation::Native(native))
+    }
+
+    pub fn hosted(
+        name: String, 
+        inputs: Vec<String>, 
+        outputs: Vec<String>, 
+        blocks: Vec<Block>,
+    ) -> Lansky<Self> {
+        let proto = Proto { name, inputs, outputs };
+        Self::new(proto.clone(), Implementation::Hosted(Procedure::new(proto, blocks)))
+    }
+
+    fn new(proto: Proto, implementation: Implementation) -> Lansky<Self> {
+        for i0 in 0..proto.inputs.len() {
+            for i1 in i0+1..proto.inputs.len() {
+                if proto.inputs[i0] == proto.inputs[i1] { 
+                    return Err(LanskyError::DuplicateInput { name: proto.inputs[i0].clone(), i0, i1 }) 
+                }
+            }
+        }
+
+        for i0 in 0..proto.outputs.len() {
+            for i1 in i0+1..proto.outputs.len() {
+                if proto.outputs[i0] == proto.outputs[i1] { 
+                    return Err(LanskyError::DuplicateOutput { name: proto.outputs[i0].clone(), i0, i1 }) 
+                }
+            }
+        }
+
+        // TODO: Validate the code in some way?
+        // Not needed for native devices
+
+        Ok(Device { proto, implementation })
+    }
+
+    pub(crate) fn analyze(&self, rack: &Rack) -> Lansky<()> {
+        match &self.implementation {
+            Implementation::Native(_) => {}
+            Implementation::Hosted(h) => {
+                h.analyze(rack)?;
+            }
+        }
+        Ok(())
+    }
+
+    pub fn get_proto(&self) -> &Proto {
+        &self.proto
+    }
+
+    pub(crate) fn invoke_named(&self, rack: &Rack, mut inputs: HashMap<String, Channel>) -> Lansky<HashMap<String, Channel>> {
+        let expected = self.proto.inputs.len();
+        let got = inputs.len();
+        if expected != got { return Err(LanskyError::WrongNInputs { expected, got }) }
+
+        let mut inputs_2 = Vec::with_capacity(self.proto.inputs.len());
+        for i in self.proto.inputs.iter() {
+            let Some(channel_in) = inputs.remove(i) else {
+                return Err(LanskyError::MissingInput { name: i.clone() })
+            };
+            inputs_2.push(channel_in)
+        }
+        for i in inputs.keys() {
+            if !self.proto.inputs.contains(i) {
+                return Err(LanskyError::UnknownInput { name: i.clone() })
+            }
+        }
+
+        let outputs = self.invoke_positional(rack, inputs_2)?;
+
+        let mut outputs_2 = HashMap::new();
+        for (k, v) in self.proto.outputs.iter().zip(outputs.into_iter()) {
+            outputs_2.insert(k.clone(), v);
+        }
+        Ok(outputs_2)
+    }
+
+    pub(crate) fn invoke_positional(&self, rack: &Rack, inputs: Vec<Channel>) -> Lansky<Vec<Channel>> {
+        let expected = self.proto.inputs.len();
+        let got = inputs.len();
+        if expected != got { return Err(LanskyError::WrongNInputs { expected, got }) }
+        let outputs = match &self.implementation {
+            Implementation::Native(f) => f(inputs)?,
+            Implementation::Hosted(procedure) => procedure.invoke(rack, inputs)?,
+        };
+
+        let expected = self.proto.outputs.len();
+        let got = outputs.len();
+        if expected != got { return Err(LanskyError::WrongNOutputs { expected, got }) }
+        Ok(outputs)
+    }
+}

src/error.rs

@@ -0,0 +1,38 @@
+pub type Lansky<T> = Result<T, LanskyError>;
+
+#[derive(Debug)]
+pub enum LanskyError {
+    DuplicateDevice { name: String },
+    UnknownDevice { name: String },
+
+    DuplicateInput { name: String, i0: usize, i1: usize },
+    DuplicateOutput { name: String, i0: usize, i1: usize },
+    
+    MissingInput { name: String },
+    UnknownInput { name: String },
+
+    WrongNInputs { expected: usize, got: usize },
+    WrongNOutputs { expected: usize, got: usize },
+
+    NoFirstBlock, 
+
+    WrongNStack { why: LanskyStackReason, expected: usize, got: usize },
+
+    MissingRegA { i: usize },
+    MissingRegZ { i: usize },
+
+    WrongNChannels { expected: usize, got: usize },
+
+    IO(std::io::Error),
+}
+
+#[derive(Debug)]
+pub enum LanskyStackReason {
+    CannotDupEmptyStack,
+    CannotOupEmptyStack,
+    CannotPopEmptyStack,
+
+    BlockMustEndWithEmptyStack,
+
+    InvokeNInputs
+}

src/main.rs

@@ -0,0 +1,98 @@
+// TODOs:
+// Generate at 88200Hz, downsample to 44100Hz
+// Parser for assembly language
+// More context in error messages
+// Replace the sample type with something more Pico 8 fixedpoint-like (right now we are always falling down on the i64 interface)
+// Use the _top_ part when coercing the sample type to an i32
+// jmp and similar instructions
+// Use primarily the named interface and allow defaulting
+// Channel-like objects that produce a constant value 
+
+use std::{path::Path, fs::File};
+
+use audio::{Sample, Channel};
+use device::Device;
+use error::{Lansky, LanskyError};
+use rack::Rack;
+use vm::{Block, BodyInstruction, ExitInstruction, MovSrc, OupDst, RegZ};
+
+mod audio;
+mod error;
+mod device;
+mod standard_devices;
+mod rack;
+mod vm;
+
+fn main() {
+    main_err().expect("crash:");
+}
+
+
+fn main_err() -> Lansky<()> {
+    let mut rack = Rack::new();
+
+    rack.add_device(Device::hosted(
+        "main".to_string(),
+        vec![],
+        vec!["audio".to_string()],
+        vec![
+            Block {
+                name: "entry".to_string(),
+                body: vec![
+                    BodyInstruction::New(MovSrc::Imm(Sample(0)), MovSrc::Imm(Sample(100000)), MovSrc::Imm(Sample(440))),
+                    BodyInstruction::Invoke("gensin".to_string(), 1, 1),
+                    BodyInstruction::Pop(OupDst::Z(RegZ(0))),
+                ],
+                exit: ExitInstruction::Exit,
+            }
+        ],
+    )?)?;
+
+    rack.analyze_all()?;
+
+    let result = 
+        rack.invoke_positional("main", vec![])?;
+
+    export(Path::new("example.wav"), result)?;
+
+    Ok(())
+}
+
+fn export(path: &Path, audio: Vec<Channel>) -> Lansky<()> {
+    match &audio[..] {
+        [mono] => {
+            let header = wav::Header::new(
+                wav::header::WAV_FORMAT_PCM,
+                1,
+                44100,
+                16
+            );
+
+            let mut out_file = File::create(path).map_err(|e| LanskyError::IO(e))?;
+            let data = channel_to_data(&mono);
+            wav::write(header, &data, &mut out_file).map_err(|e| LanskyError::IO(e))?;
+
+            Ok(())
+        },
+        _ => {
+            return Err(LanskyError::WrongNChannels { expected: 1, got: audio.len() })
+        }
+    }
+}
+
+fn channel_to_data(channel: &Channel) -> wav::BitDepth {
+    let mut v: Vec<i16> = vec![];
+    for i in channel.bounds().informal {
+        v.push(channel[i].to_i16_sample())
+    }
+    wav::BitDepth::Sixteen(v)
+}
+
+/*
+fn main_err() -> std::io::Result<()> {
+    let mut out_file = File::create(Path::new("output.wav"))?;
+    wav::write(header, &data, &mut out_file)?;
+
+    Ok(())
+}
+*/

src/rack.rs

@@ -0,0 +1,56 @@
+use std::collections::HashMap;
+
+use crate::{device::{Device, Proto}, error::{Lansky, LanskyError}, standard_devices, audio::Channel};
+
+pub struct Rack {
+    devices: HashMap<String, Device>
+}
+
+impl Rack {
+    pub fn new() -> Self {
+        let mut r = Rack {
+            devices: HashMap::new()
+        };
+        standard_devices::augment(&mut r);
+        r
+    }
+
+    pub fn analyze_all(&self) -> Lansky<()> {
+        for d in self.devices.values() {
+            d.analyze(self)?;
+        }
+        Ok(())
+    }
+
+    pub fn add_device(&mut self, device: Device) -> Lansky<()> {
+        if self.devices.contains_key(&device.get_proto().name) {
+            return Err(LanskyError::DuplicateDevice { name: device.get_proto().name.clone() })
+        }
+
+        let name = device.get_proto().name.clone();
+        self.devices.insert(name, device);
+
+        Ok(())
+    }
+
+    fn get_device(&self, name: &str) -> Lansky<&Device> {
+        let Some(device) = self.devices.get(name) else {
+            return Err(LanskyError::UnknownDevice { name: name.to_string() })
+        };
+
+        Ok(device)
+    }
+
+    pub fn invoke_named(&self, name: &str, inputs: HashMap<String, Channel>) -> Lansky<HashMap<String, Channel>> {
+        self.get_device(name)?.invoke_named(self, inputs)
+    }
+
+    pub fn invoke_positional(&self, name: &str, inputs: Vec<Channel>) -> Lansky<Vec<Channel>> {
+        self.get_device(name)?.invoke_positional(self, inputs)
+    }
+
+    pub fn get_proto(&self, name: &str) -> Lansky<&Proto> {
+        Ok(self.get_device(name)?.get_proto())
+    }
+
+}

src/standard_devices/mod.rs

@@ -0,0 +1,33 @@
+use std::f32::consts::PI;
+
+use crate::{rack::Rack, device::Device, audio::{Channel, Sample}, error::Lansky};
+
+pub fn augment(r: &mut Rack) -> Lansky<()> {
+    r.add_device(Device::native(
+        "gensin".to_string(), 
+        vec!["frequency".to_string()],
+        vec!["signal".to_string()],
+        gensin
+    )?)?;
+
+    Ok(())
+}
+
+fn gensin(mut chans: Vec<Channel>) -> Lansky<Vec<Channel>> {
+    assert!(chans.len() == 1);
+    let inp = chans.pop().expect("must be one channel");
+
+    let mut pos = 0.0;
+    let sr = 44100.0;
+
+    let mut oup = Channel::new(inp.formal());
+
+    for i in inp.bounds().informal {
+        let freq = inp[i].0 as f32;
+        pos += freq/sr;
+        pos %= 1.0;
+        oup[i] = Sample(((pos * PI * 2.0).sin() * i32::MAX as f32) as i64);
+    }
+
+    Ok(vec![oup])
+}

src/vm.rs

@@ -0,0 +1,519 @@
+use std::cell::Cell;
+
+use crate::{audio::{Channel, Sample}, error::{Lansky, LanskyError, LanskyStackReason}, device::Proto, rack::Rack};
+
+pub(crate) struct Procedure {
+    proto: Proto,
+    blocks: Vec<Block>,
+    analysis: Cell<Option<Analysis>>,
+}
+
+#[derive(Clone, Copy)]
+struct Analysis {
+    stack_depth: usize,
+
+    proto_n_inputs: usize,
+    proto_n_outputs: usize,
+
+    n_reg_ls: usize,
+}
+
+pub struct Block {
+    pub name: String,
+    pub body: Vec<BodyInstruction>,
+    pub exit: ExitInstruction
+}
+
+pub enum BodyInstruction {
+    Mov(MovType, MovDst, MovSrc),
+    Range(RangeDst, i32, i32),
+    Inp(InpSrc),
+    Dup(),
+    Oup(MovType, OupDst),
+    Pop(OupDst),
+    New(MovSrc, MovSrc, MovSrc),
+    Invoke(String, usize, usize),
+}
+
+pub enum ExitInstruction {
+    Exit,
+}
+
+pub enum MovType { Mov, Add, Xor }
+
+#[derive(Clone, Copy)] pub enum MovDst { L(RegL), R(RegR), Z(RegZ), Ix }
+#[derive(Clone, Copy)] pub enum MovSrc { A(RegA), L(RegL), R(RegR), Z(RegZ), Ix, Imm(Sample) }
+#[derive(Clone, Copy)] pub enum RangeDst { A(RegA), L(RegL), Z(RegZ) }
+#[derive(Clone, Copy)] pub enum InpSrc { A(RegA), L(RegL), Z(RegZ) }
+#[derive(Clone, Copy)] pub enum OupDst { L(RegL), Z(RegZ) }
+
+impl OupDst {
+    fn to_mov_dst(self) -> MovDst {
+        match self {
+            Self::L(l) => MovDst::L(l),
+            Self::Z(z) => MovDst::Z(z),
+        }
+    }
+}
+
+#[derive(Clone, Copy)] pub struct RegA(pub u8);
+#[derive(Clone, Copy)] pub struct RegL(pub u8);
+#[derive(Clone, Copy)] pub struct RegR(pub u8);
+#[derive(Clone, Copy)] pub struct RegZ(pub u8);
+
+struct Scope {
+    ix: Sample,
+
+    reg_as: Vec<Channel>,
+    reg_ls: Vec<Channel>,
+    reg_rs: [Sample; 256],
+    reg_zs: Vec<Channel>,
+
+    loop_as: [LoopRange; 256],
+    loop_ls: [LoopRange; 256],
+    loop_zs: [LoopRange; 256],
+}
+
+#[derive(Clone, Copy)]
+struct LoopRange {
+    start: i32,
+    length: i32, 
+}
+
+impl Default for LoopRange {
+    fn default() -> Self {
+        Self { start: 0, length: 0 }
+    }
+}
+
+impl Scope {
+    fn new(analysis: Analysis, inputs: Vec<Channel>) -> Scope {
+        assert_eq!(inputs.len(), analysis.proto_n_inputs); // analysis is done elsewhere
+
+        let reg_as: Vec<Channel> = inputs;
+        let mut reg_ls: Vec<Channel> = vec![];
+        let reg_rs: [Sample; 256] = [Sample::default(); 256];
+        let mut reg_zs: Vec<Channel> = vec![];
+
+        for _ in 0..analysis.n_reg_ls { reg_ls.push(Channel::blank()); }
+        for _ in 0..analysis.proto_n_outputs { reg_zs.push(Channel::blank()); }
+
+        Scope {
+            ix: Sample(0),
+
+            reg_as, 
+            reg_ls, 
+            reg_rs, 
+            reg_zs,
+
+            loop_as: [LoopRange::default(); 256],
+            loop_ls: [LoopRange::default(); 256],
+            loop_zs: [LoopRange::default(); 256],
+        }
+    }
+
+    fn exit(self) -> Vec<Channel> {
+        self.reg_zs
+    }
+
+    fn read(&self, src: MovSrc) -> Sample {
+        let flat_ix = self.ix.0 as i32;
+        let (chan, loop_) = match src {
+            MovSrc::A(RegA(a)) => {
+                let a = a as usize;
+                (&self.reg_as[a], &self.loop_as[a])
+            }
+            MovSrc::L(RegL(l)) => {
+                let l = l as usize;
+                (&self.reg_ls[l], &self.loop_ls[l])
+            }
+            MovSrc::R(RegR(r)) => {
+                let r = r as usize;
+                return self.reg_rs[r]
+            }
+            MovSrc::Z(RegZ(z)) => {
+                let z = z as usize;
+                (&self.reg_zs[z], &self.loop_zs[z])
+            }
+            MovSrc::Ix => return self.ix,
+            MovSrc::Imm(i) => return i,
+        };
+
+        let mut ix = flat_ix;
+        if loop_.length != 0 { ix %= loop_.length; }
+        ix += chan.formal().start + loop_.start;
+
+        chan[ix]
+    }
+
+    fn write(&mut self, ty: &MovType, dst: MovDst, value: Sample, offset: i32) {
+        let flat_ix = self.ix.0 as i32;
+        let (chan, loop_) = match dst {
+            MovDst::L(RegL(l)) => {
+                let l = l as usize;
+                (&mut self.reg_ls[l], &self.loop_ls[l])
+            }
+            MovDst::R(RegR(r)) => {
+                let r = r as usize;
+                self.reg_rs[r] = value; return
+            }
+            MovDst::Z(RegZ(z)) => {
+                let z = z as usize;
+                (&mut self.reg_zs[z], &self.loop_zs[z])
+            }
+            MovDst::Ix => { self.ix = value; return }
+        };
+
+        let mut ix = flat_ix + offset;
+        if loop_.length != 0 { ix %= loop_.length; }
+        ix += chan.formal().start + loop_.start;
+
+        chan[ix] = value
+    }
+
+    fn replace(&mut self, dst: OupDst, value: Channel) {
+        match dst {
+            OupDst::L(RegL(l)) => { 
+                self.reg_ls[l as usize] = value; 
+                self.loop_ls[l as usize] = LoopRange::default() 
+            }
+            OupDst::Z(RegZ(z)) => { 
+                self.reg_zs[z as usize] = value; 
+                self.loop_zs[z as usize] = LoopRange::default() 
+            }
+        }
+    }
+
+    fn apply_range(&mut self, dst: RangeDst, start: i32, length: i32) {
+        let lr = LoopRange{start, length};
+        match dst {
+            RangeDst::A(RegA(a)) => {
+                self.loop_as[a as usize] = lr
+            }
+            RangeDst::L(RegL(l)) => {
+                self.loop_ls[l as usize] = lr
+            }
+            RangeDst::Z(RegZ(z)) => {
+                self.loop_zs[z as usize] = lr
+            }
+        }
+    }
+
+    fn inp(&self, src: InpSrc) -> Channel {
+        let (chan, loop_) = match src {
+            InpSrc::A(RegA(a)) => {
+                let a = a as usize;
+                (&self.reg_as[a], &self.loop_as[a])
+            }
+            InpSrc::L(RegL(l)) => {
+                let l = l as usize;
+                (&self.reg_ls[l], &self.loop_ls[l])
+            }
+            InpSrc::Z(RegZ(z)) => {
+                let z = z as usize;
+                (&self.reg_zs[z], &self.loop_zs[z])
+            }
+        };
+        chan.slice(loop_.start, loop_.length)
+    }
+}
+
+impl Procedure {
+    pub(crate) fn new(proto: Proto, blocks: Vec<Block>) -> Procedure {
+        Procedure {
+            proto,
+            blocks,
+            analysis: Cell::new(None),
+        }
+    }
+
+    pub fn invoke(&self, rack: &Rack, inputs: Vec<Channel>) -> Lansky<Vec<Channel>> {
+        let analysis = self.internal_analyze(rack)?;
+
+        let mut scope = Scope::new(analysis, inputs);
+        let mut stack: Vec<Channel> = vec![];
+
+        let block_ix = 0;
+        loop {
+            let block = &self.blocks[block_ix];
+            for instruction in block.body.iter() {
+                match instruction {
+                    BodyInstruction::Mov(ty, dst, src) => {
+                        scope.write(ty, *dst, scope.read(*src), 0)
+                    }
+                    BodyInstruction::Range(dst, start, len) => {
+                        scope.apply_range(*dst, *start, *len)
+                    }
+                    BodyInstruction::Inp(src) => {
+                        let slice = scope.inp(*src);
+                        stack.push(slice)
+                    }
+                    BodyInstruction::Dup() => {
+                        let top = stack.pop().expect("stack can't be empty");
+                        stack.push(top.clone())
+                    }
+                    BodyInstruction::Oup(ty, dst) => {
+                        let top = stack.pop().expect("stack can't be empty");
+                        let bounds = top.bounds();
+                        for ix in bounds.informal {
+                            let offset = ix - bounds.formal.start;
+                            scope.write(ty, dst.to_mov_dst(), top[ix], offset)
+                        }
+                    }
+                    BodyInstruction::Pop(dst) => {
+                        let top = stack.pop().expect("stack can't be empty");
+                        scope.replace(*dst, top)
+                    }
+                    BodyInstruction::New(formal_start, formal_len, fill) => {
+                        let start = scope.read(*formal_start);
+                        let len = scope.read(*formal_len);
+                        let fill = scope.read(*fill);
+                        let mut chan = Channel::new((start.0 as i32)..((start.0+len.0) as i32));
+                        for i in chan.formal() {
+                            chan[i] = fill
+                        }
+                        stack.push(chan)
+                    }
+                    BodyInstruction::Invoke(device, n_inputs, n_outputs) => {
+                        let mut inputs: Vec<Channel> = vec![]; 
+                        std::mem::swap(&mut stack, &mut inputs);
+                        assert_eq!(inputs.len(), *n_inputs);
+                        let outputs = rack.invoke_positional(device, inputs)?;
+                        assert_eq!(outputs.len(), *n_outputs);
+                        stack.extend(outputs);
+                        stack.reverse()
+                    }
+                }
+            }
+
+            match block.exit {
+                ExitInstruction::Exit => return Ok(scope.exit())
+            }
+        }
+    }
+
+    pub(crate) fn analyze(&self, rack: &Rack) -> Lansky<()> {
+        self.internal_analyze(rack)?;
+        Ok(())
+    }
+
+    fn internal_analyze(&self, rack: &Rack) -> Lansky<Analysis> {
+        if let Some(x) = self.analysis.get() { return Ok(x) }
+
+        let mut analysis = Analysis { 
+            stack_depth: 0, 
+
+            proto_n_inputs: self.proto.inputs.len(),
+            proto_n_outputs: self.proto.outputs.len(),
+
+            n_reg_ls: 0 
+        };
+
+        if self.blocks.len() == 0 {
+            return Err(LanskyError::NoFirstBlock);
+        }
+
+        for block in self.blocks.iter() {
+            block.touch_analysis(
+                &mut analysis, &|d| rack.get_proto(d).cloned()
+            )?;
+        }
+
+        self.analysis.set(Some(analysis));
+
+        return Ok(analysis)
+    }
+}
+
+
+impl Block {
+    fn touch_analysis(&self, analysis: &mut Analysis, get_proto: &impl Fn(&str) -> Lansky<Proto>) -> Lansky<()> {
+        for instruction in self.body.iter() {
+            instruction.touch_analysis(analysis, get_proto)?;
+        }
+
+        if analysis.stack_depth != 0 {
+            return Err(LanskyError::WrongNStack { 
+                why: LanskyStackReason::BlockMustEndWithEmptyStack,
+                got: analysis.stack_depth, expected: 0 
+            })
+        }
+        self.exit.touch_analysis(analysis)?;
+
+        Ok(())
+    }
+}
+
+impl BodyInstruction {
+    fn touch_analysis(&self, analysis: &mut Analysis, get_proto: &impl Fn(&str) -> Lansky<Proto>) -> Lansky<()> {
+        match self {
+            BodyInstruction::Mov(_, dst, src) => {
+                dst.touch_analysis(analysis)?;
+                src.touch_analysis(analysis)?;
+            }
+            BodyInstruction::Range(dst, _, _) => {
+                dst.touch_analysis(analysis)?;
+            }
+            BodyInstruction::Inp(src) => {
+                analysis.stack_depth += 1;
+                src.touch_analysis(analysis)?;
+            }
+            BodyInstruction::Dup() => {
+                if analysis.stack_depth == 0 {
+                    return Err(LanskyError::WrongNStack { 
+                        why: LanskyStackReason::CannotDupEmptyStack,
+                        expected: 1, got: 0 
+                    })
+                }
+                analysis.stack_depth += 1;
+            }
+            BodyInstruction::Oup(_, dst) => {
+                if analysis.stack_depth == 0 {
+                    return Err(LanskyError::WrongNStack { 
+                        why: LanskyStackReason::CannotOupEmptyStack,
+                        expected: 1, got: 0 
+                    })
+                }
+                analysis.stack_depth -= 1;
+
+                dst.touch_analysis(analysis)?;
+            }
+            BodyInstruction::Pop(dst) => {
+                if analysis.stack_depth == 0 {
+                    return Err(LanskyError::WrongNStack { 
+                        why: LanskyStackReason::CannotPopEmptyStack,
+                        expected: 1, got: 0 
+                    })
+                }
+                analysis.stack_depth -= 1;
+
+                dst.touch_analysis(analysis)?;
+            }
+            BodyInstruction::New(formal_start, formal_len, fill) => {
+                analysis.stack_depth += 1;
+
+                formal_start.touch_analysis(analysis)?;
+                formal_len.touch_analysis(analysis)?;
+                fill.touch_analysis(analysis)?;
+            }
+            BodyInstruction::Invoke(device, n_inputs, n_outputs) => {
+                let proto = get_proto(device)?;
+
+                let actual_n_inputs = proto.inputs.len();
+                let actual_n_outputs = proto.outputs.len();
+
+                if *n_inputs != actual_n_inputs {
+                    return Err(LanskyError::WrongNInputs { expected: actual_n_inputs, got: *n_inputs })
+                }
+
+                if *n_outputs != actual_n_outputs {
+                    return Err(LanskyError::WrongNInputs { expected: actual_n_inputs, got: *n_outputs })
+                }
+
+                if analysis.stack_depth != *n_inputs {
+                    return Err(LanskyError::WrongNStack {
+                        why: LanskyStackReason::InvokeNInputs,
+                        expected: *n_inputs,
+                        got: analysis.stack_depth,
+                    })
+                }
+                analysis.stack_depth = *n_outputs;
+            }
+        }
+        Ok(())
+    }
+}
+
+impl ExitInstruction {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            ExitInstruction::Exit => {}
+        }
+        Ok(())
+    }
+}
+
+impl MovDst {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            Self::L(l) => l.touch_analysis(analysis),
+            Self::R(r) => r.touch_analysis(analysis),
+            Self::Z(z) => z.touch_analysis(analysis),
+            Self::Ix => Ok(()),
+        }
+    }
+}
+
+impl MovSrc {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            Self::A(a) => a.touch_analysis(analysis),
+            Self::L(l) => l.touch_analysis(analysis),
+            Self::R(r) => r.touch_analysis(analysis),
+            Self::Z(z) => z.touch_analysis(analysis),
+            Self::Ix => Ok(()),
+            Self::Imm(_) => Ok(()),
+        }
+    }
+}
+
+impl RangeDst {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            Self::A(a) => a.touch_analysis(analysis),
+            Self::L(l) => l.touch_analysis(analysis),
+            Self::Z(z) => z.touch_analysis(analysis),
+        }
+    }
+}
+
+impl InpSrc {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            Self::A(a) => a.touch_analysis(analysis),
+            Self::L(l) => l.touch_analysis(analysis),
+            Self::Z(z) => z.touch_analysis(analysis),
+        }
+    }
+}
+
+impl OupDst {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        match self {
+            Self::L(l) => l.touch_analysis(analysis),
+            Self::Z(z) => z.touch_analysis(analysis),
+        }
+    }
+}
+
+
+impl RegA {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        if self.0 as usize >= analysis.proto_n_inputs {
+            return Err(LanskyError::MissingRegA { i: self.0 as usize });
+        }
+        Ok(())
+    }
+}
+
+impl RegL {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        analysis.n_reg_ls = analysis.n_reg_ls.max(self.0 as usize);
+        Ok(())
+    }
+}
+
+impl RegR {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        Ok(())
+    }
+}
+
+impl RegZ {
+    fn touch_analysis(&self, analysis: &mut Analysis) -> Lansky<()> {
+        if self.0 as usize >= analysis.proto_n_outputs {
+            return Err(LanskyError::MissingRegZ { i: self.0 as usize });
+        }
+        Ok(())
+    }
+}