Per-operation CORDIC config system with ZCD archive integration

crates/cord-cordic/Cargo.toml

@@ -10,3 +10,6 @@ categories = ["mathematics", "no-std"]
 
 [dependencies]
 cord-trig = { path = "../cord-trig" }
+serde = { version = "1", features = ["derive"] }
+toml = "0.8"
+regex = "1"

crates/cord-cordic/src/compiler.rs

@@ -1,4 +1,6 @@
+use std::collections::BTreeMap;
 use cord_trig::{TrigGraph, TrigOp};
+use crate::config::{CordicConfig, CordicOp};
 use crate::ops::*;
 
 /// A compiled CORDIC program ready for binary serialization or execution.
@@ -6,11 +8,29 @@ use crate::ops::*;
 /// Each instruction produces its result into a slot matching its index.
 /// The instruction list parallels the TrigGraph node list — compilation
 /// is a direct 1:1 mapping with constants folded to fixed-point.
+///
+/// Supports per-operation iteration counts via `tables`: each unique
+/// iteration count gets its own atan table and gain constant. Instructions
+/// index into `tables` via `instr_table_idx`.
 #[derive(Debug, Clone)]
 pub struct CORDICProgram {
     pub word_bits: u8,
     pub instructions: Vec<CORDICInstr>,
     pub output: u32,
+    /// One entry per unique iteration count.
+    pub tables: Vec<CordicTable>,
+    /// Maps instruction index → table index. Only meaningful for CORDIC ops;
+    /// non-CORDIC instructions have 0 here (ignored at eval time).
+    pub instr_table_idx: Vec<u8>,
+    /// Legacy fields for backward compat with single-table programs.
+    pub atan_table: Vec<i64>,
+    pub gain: i64,
+}
+
+/// Precomputed atan table + gain for a specific iteration count.
+#[derive(Debug, Clone)]
+pub struct CordicTable {
+    pub iterations: u8,
     pub atan_table: Vec<i64>,
     pub gain: i64,
 }
@@ -18,11 +38,12 @@ pub struct CORDICProgram {
 #[derive(Debug, Clone)]
 pub struct CompileConfig {
     pub word_bits: u8,
+    pub cordic: Option<CordicConfig>,
 }
 
 impl Default for CompileConfig {
     fn default() -> Self {
-        Self { word_bits: 32 }
+        Self { word_bits: 32, cordic: None }
     }
 }
 
@@ -30,15 +51,80 @@ impl CORDICProgram {
     /// Compile a TrigGraph into a CORDIC program.
     ///
     /// Each TrigOp node becomes one CORDICInstr. Constants are converted
-    /// from f64 to fixed-point at compile time. Everything else is a
+    /// from f64 to fixed-point at compile time. Per-operation iteration
-    /// direct structural mapping.
+    /// counts are resolved from the CordicConfig if present, otherwise
+    /// all ops use word_bits as their iteration count.
     pub fn compile(graph: &TrigGraph, config: &CompileConfig) -> Self {
         let frac_bits = config.word_bits - 1;
         let to_fixed = |val: f64| -> i64 {
             (val * (1i64 << frac_bits) as f64).round() as i64
         };
 
+        let cordic_cfg = config.cordic.as_ref().map(|c| c.clone())
+            .unwrap_or_else(|| {
+                let mut c = CordicConfig::default();
+                c.word_bits = config.word_bits;
+                c.default_f = config.word_bits;
+                c
+            });
+
+        // Build tables for each unique iteration count
+        let unique_counts = cordic_cfg.unique_iteration_counts();
+        let mut count_to_table_idx: BTreeMap<u8, u8> = BTreeMap::new();
+        let mut tables = Vec::new();
+        for &iters in &unique_counts {
+            count_to_table_idx.insert(iters, tables.len() as u8);
+            tables.push(CordicTable {
+                iterations: iters,
+                atan_table: atan_table(iters),
+                gain: cordic_gain(iters, frac_bits),
+            });
+        }
+
+        let default_table_idx = count_to_table_idx
+            .get(&cordic_cfg.default_f)
+            .copied()
+            .unwrap_or_else(|| {
+                // Ensure default has a table entry
+                let idx = tables.len() as u8;
+                tables.push(CordicTable {
+                    iterations: cordic_cfg.default_f,
+                    atan_table: atan_table(cordic_cfg.default_f),
+                    gain: cordic_gain(cordic_cfg.default_f, frac_bits),
+                });
+                idx
+            });
+
+        let resolve_table = |cop: CordicOp| -> u8 {
+            let iters = cordic_cfg.iterations_for(cop);
+            count_to_table_idx.get(&iters).copied().unwrap_or(default_table_idx)
+        };
+
+        let mut instr_table_idx = Vec::with_capacity(graph.nodes.len());
+
         let instructions: Vec<CORDICInstr> = graph.nodes.iter().map(|op| {
+            let tidx = match op {
+                TrigOp::Sin(_) => resolve_table(CordicOp::Sin),
+                TrigOp::Cos(_) => resolve_table(CordicOp::Cos),
+                TrigOp::Tan(_) => resolve_table(CordicOp::Tan),
+                TrigOp::Asin(_) => resolve_table(CordicOp::Asin),
+                TrigOp::Acos(_) => resolve_table(CordicOp::Acos),
+                TrigOp::Atan(_) => resolve_table(CordicOp::Atan),
+                TrigOp::Sinh(_) => resolve_table(CordicOp::Sinh),
+                TrigOp::Cosh(_) => resolve_table(CordicOp::Cosh),
+                TrigOp::Tanh(_) => resolve_table(CordicOp::Tanh),
+                TrigOp::Asinh(_) => resolve_table(CordicOp::Asinh),
+                TrigOp::Acosh(_) => resolve_table(CordicOp::Acosh),
+                TrigOp::Atanh(_) => resolve_table(CordicOp::Atanh),
+                TrigOp::Sqrt(_) => resolve_table(CordicOp::Sqrt),
+                TrigOp::Exp(_) => resolve_table(CordicOp::Exp),
+                TrigOp::Ln(_) => resolve_table(CordicOp::Ln),
+                TrigOp::Hypot(_, _) => resolve_table(CordicOp::Hypot),
+                TrigOp::Atan2(_, _) => resolve_table(CordicOp::Atan2),
+                _ => 0,
+            };
+            instr_table_idx.push(tidx);
+
             match op {
                 TrigOp::InputX => CORDICInstr::InputX,
                 TrigOp::InputY => CORDICInstr::InputY,
@@ -77,12 +163,21 @@ impl CORDICProgram {
             }
         }).collect();
 
+        // Legacy single-table fields use the first table (or default)
+        let primary = tables.first().cloned().unwrap_or_else(|| CordicTable {
+            iterations: config.word_bits,
+            atan_table: atan_table(config.word_bits),
+            gain: cordic_gain(config.word_bits, frac_bits),
+        });
+
         CORDICProgram {
             word_bits: config.word_bits,
             instructions,
             output: graph.output,
-            atan_table: atan_table(config.word_bits),
+            tables,
-            gain: cordic_gain(config.word_bits, frac_bits),
+            instr_table_idx,
+            atan_table: primary.atan_table,
+            gain: primary.gain,
         }
     }
 
@@ -153,6 +248,15 @@ impl CORDICProgram {
             pos += consumed;
         }
 
-        Some(CORDICProgram { word_bits, instructions, output, atan_table, gain })
+        let tables = vec![CordicTable {
+            iterations: word_bits,
+            atan_table: atan_table.clone(),
+            gain,
+        }];
+        let instr_table_idx = vec![0u8; instructions.len()];
+
+        Some(CORDICProgram {
+            word_bits, instructions, output, tables, instr_table_idx, atan_table, gain,
+        })
     }
 }

crates/cord-cordic/src/config.rs

@@ -0,0 +1,305 @@
+use std::collections::BTreeMap;
+use cord_trig::{TrigGraph, TrigOp};
+use serde::{Deserialize, Serialize};
+
+/// Canonical name for each CORDIC-consuming operation.
+/// Non-CORDIC ops (Add, Sub, etc.) don't appear here.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
+#[serde(rename_all = "lowercase")]
+pub enum CordicOp {
+    Sin,
+    Cos,
+    Tan,
+    Asin,
+    Acos,
+    Atan,
+    Sinh,
+    Cosh,
+    Tanh,
+    Asinh,
+    Acosh,
+    Atanh,
+    Sqrt,
+    Exp,
+    Ln,
+    Hypot,
+    Atan2,
+}
+
+impl CordicOp {
+    pub fn name(&self) -> &'static str {
+        match self {
+            Self::Sin => "sin",
+            Self::Cos => "cos",
+            Self::Tan => "tan",
+            Self::Asin => "asin",
+            Self::Acos => "acos",
+            Self::Atan => "atan",
+            Self::Sinh => "sinh",
+            Self::Cosh => "cosh",
+            Self::Tanh => "tanh",
+            Self::Asinh => "asinh",
+            Self::Acosh => "acosh",
+            Self::Atanh => "atanh",
+            Self::Sqrt => "sqrt",
+            Self::Exp => "exp",
+            Self::Ln => "ln",
+            Self::Hypot => "hypot",
+            Self::Atan2 => "atan2",
+        }
+    }
+
+    pub fn all() -> &'static [CordicOp] {
+        &[
+            Self::Sin, Self::Cos, Self::Tan,
+            Self::Asin, Self::Acos, Self::Atan,
+            Self::Sinh, Self::Cosh, Self::Tanh,
+            Self::Asinh, Self::Acosh, Self::Atanh,
+            Self::Sqrt, Self::Exp, Self::Ln,
+            Self::Hypot, Self::Atan2,
+        ]
+    }
+
+    pub fn from_name(s: &str) -> Option<Self> {
+        Self::all().iter().find(|op| op.name() == s).copied()
+    }
+}
+
+/// On-disk TOML representation.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct CordicConfigFile {
+    #[serde(default)]
+    pub defaults: Defaults,
+    #[serde(default, rename = "override")]
+    pub overrides: Vec<Override>,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Defaults {
+    #[serde(default = "default_word_bits")]
+    pub word_bits: u8,
+    #[serde(default = "default_f")]
+    pub f: u8,
+}
+
+impl Default for Defaults {
+    fn default() -> Self {
+        Self {
+            word_bits: default_word_bits(),
+            f: default_f(),
+        }
+    }
+}
+
+fn default_word_bits() -> u8 { 32 }
+fn default_f() -> u8 { 32 }
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct Override {
+    /// Regex pattern matching operation names (e.g. "sin|cos", "sinh|cosh|tanh")
+    pub op: String,
+    /// Iteration count override
+    pub f: u8,
+}
+
+/// Resolved configuration: each operation has a concrete iteration count.
+#[derive(Debug, Clone)]
+pub struct CordicConfig {
+    pub word_bits: u8,
+    pub default_f: u8,
+    /// Per-operation iteration counts. Only contains ops actually used.
+    pub ops: BTreeMap<CordicOp, u8>,
+}
+
+impl Default for CordicConfig {
+    fn default() -> Self {
+        Self {
+            word_bits: 32,
+            default_f: 32,
+            ops: BTreeMap::new(),
+        }
+    }
+}
+
+impl CordicConfig {
+    /// Scan a TrigGraph and build a config with default f for every CORDIC op found.
+    pub fn scan(graph: &TrigGraph) -> Self {
+        let mut config = Self::default();
+        for op in &graph.nodes {
+            if let Some(cop) = trig_op_to_cordic(op) {
+                config.ops.entry(cop).or_insert(config.default_f);
+            }
+        }
+        config
+    }
+
+    /// Scan a TrigGraph and build config from a file representation.
+    /// Overrides are applied in order; last match wins.
+    pub fn from_file(graph: &TrigGraph, file: &CordicConfigFile) -> Self {
+        let mut config = Self {
+            word_bits: file.defaults.word_bits,
+            default_f: file.defaults.f,
+            ops: BTreeMap::new(),
+        };
+
+        // Populate with defaults for all ops found in graph
+        for op in &graph.nodes {
+            if let Some(cop) = trig_op_to_cordic(op) {
+                config.ops.entry(cop).or_insert(config.default_f);
+            }
+        }
+
+        // Apply overrides in order
+        for ov in &file.overrides {
+            if let Ok(re) = regex::Regex::new(&ov.op) {
+                for (&cop, f_val) in config.ops.iter_mut() {
+                    if re.is_match(cop.name()) {
+                        *f_val = ov.f;
+                    }
+                }
+            }
+        }
+
+        config
+    }
+
+    /// Parse from TOML string, resolving against the given graph.
+    pub fn from_toml(graph: &TrigGraph, toml_str: &str) -> Result<Self, toml::de::Error> {
+        let file: CordicConfigFile = toml::from_str(toml_str)?;
+        Ok(Self::from_file(graph, &file))
+    }
+
+    /// Serialize the current config to a TOML file representation.
+    pub fn to_file(&self) -> CordicConfigFile {
+        // Group ops by f value to produce compact overrides
+        let mut by_f: BTreeMap<u8, Vec<CordicOp>> = BTreeMap::new();
+        for (&op, &f) in &self.ops {
+            if f != self.default_f {
+                by_f.entry(f).or_default().push(op);
+            }
+        }
+
+        let overrides = by_f.into_iter().map(|(f, ops)| {
+            let pattern = ops.iter()
+                .map(|op| op.name())
+                .collect::<Vec<_>>()
+                .join("|");
+            Override { op: pattern, f }
+        }).collect();
+
+        CordicConfigFile {
+            defaults: Defaults {
+                word_bits: self.word_bits,
+                f: self.default_f,
+            },
+            overrides,
+        }
+    }
+
+    /// Serialize to TOML string.
+    pub fn to_toml(&self) -> String {
+        let file = self.to_file();
+        toml::to_string_pretty(&file).unwrap_or_default()
+    }
+
+    /// Get iteration count for a specific operation.
+    pub fn iterations_for(&self, op: CordicOp) -> u8 {
+        self.ops.get(&op).copied().unwrap_or(self.default_f)
+    }
+
+    /// Get the set of unique iteration counts used, for precomputing tables.
+    pub fn unique_iteration_counts(&self) -> Vec<u8> {
+        let mut counts: Vec<u8> = self.ops.values().copied().collect();
+        counts.sort();
+        counts.dedup();
+        if counts.is_empty() {
+            counts.push(self.default_f);
+        }
+        counts
+    }
+}
+
+fn trig_op_to_cordic(op: &TrigOp) -> Option<CordicOp> {
+    match op {
+        TrigOp::Sin(_) => Some(CordicOp::Sin),
+        TrigOp::Cos(_) => Some(CordicOp::Cos),
+        TrigOp::Tan(_) => Some(CordicOp::Tan),
+        TrigOp::Asin(_) => Some(CordicOp::Asin),
+        TrigOp::Acos(_) => Some(CordicOp::Acos),
+        TrigOp::Atan(_) => Some(CordicOp::Atan),
+        TrigOp::Sinh(_) => Some(CordicOp::Sinh),
+        TrigOp::Cosh(_) => Some(CordicOp::Cosh),
+        TrigOp::Tanh(_) => Some(CordicOp::Tanh),
+        TrigOp::Asinh(_) => Some(CordicOp::Asinh),
+        TrigOp::Acosh(_) => Some(CordicOp::Acosh),
+        TrigOp::Atanh(_) => Some(CordicOp::Atanh),
+        TrigOp::Sqrt(_) => Some(CordicOp::Sqrt),
+        TrigOp::Exp(_) => Some(CordicOp::Exp),
+        TrigOp::Ln(_) => Some(CordicOp::Ln),
+        TrigOp::Hypot(_, _) => Some(CordicOp::Hypot),
+        TrigOp::Atan2(_, _) => Some(CordicOp::Atan2),
+        _ => None,
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use cord_trig::ir::TrigOp;
+
+    #[test]
+    fn scan_discovers_ops() {
+        let mut g = TrigGraph::new();
+        let angle = g.push(TrigOp::Const(1.0));
+        let s = g.push(TrigOp::Sin(angle));
+        let c = g.push(TrigOp::Cos(angle));
+        let _ = g.push(TrigOp::Add(s, c));
+        g.set_output(3);
+
+        let config = CordicConfig::scan(&g);
+        assert!(config.ops.contains_key(&CordicOp::Sin));
+        assert!(config.ops.contains_key(&CordicOp::Cos));
+        assert!(!config.ops.contains_key(&CordicOp::Tan));
+        assert_eq!(config.ops.len(), 2);
+    }
+
+    #[test]
+    fn override_applies() {
+        let mut g = TrigGraph::new();
+        let a = g.push(TrigOp::Const(1.0));
+        let _ = g.push(TrigOp::Sin(a));
+        let _ = g.push(TrigOp::Cos(a));
+        let _ = g.push(TrigOp::Sinh(a));
+        g.set_output(1);
+
+        let file = CordicConfigFile {
+            defaults: Defaults { word_bits: 32, f: 32 },
+            overrides: vec![
+                Override { op: "sin|cos".into(), f: 24 },
+                Override { op: "sinh".into(), f: 16 },
+            ],
+        };
+
+        let config = CordicConfig::from_file(&g, &file);
+        assert_eq!(config.iterations_for(CordicOp::Sin), 24);
+        assert_eq!(config.iterations_for(CordicOp::Cos), 24);
+        assert_eq!(config.iterations_for(CordicOp::Sinh), 16);
+    }
+
+    #[test]
+    fn toml_roundtrip() {
+        let mut g = TrigGraph::new();
+        let a = g.push(TrigOp::Const(1.0));
+        let _ = g.push(TrigOp::Sin(a));
+        let _ = g.push(TrigOp::Cos(a));
+        g.set_output(1);
+
+        let mut config = CordicConfig::scan(&g);
+        config.ops.insert(CordicOp::Sin, 24);
+
+        let toml_str = config.to_toml();
+        let config2 = CordicConfig::from_toml(&g, &toml_str).unwrap();
+        assert_eq!(config2.iterations_for(CordicOp::Sin), 24);
+        assert_eq!(config2.iterations_for(CordicOp::Cos), 32);
+    }
+}

crates/cord-cordic/src/eval.rs

@@ -1,4 +1,6 @@
 use cord_trig::{TrigGraph, TrigOp};
+use crate::compiler::{CORDICProgram, CordicTable};
+use crate::ops::{atan_table, cordic_gain};
 
 /// CORDIC evaluator: evaluates a TrigGraph using only integer
 /// shifts, adds, and comparisons. No floating point trig.
@@ -6,33 +8,32 @@ use cord_trig::{TrigGraph, TrigOp};
 /// Proof that the entire pipeline compiles down to
 /// binary arithmetic — shift, add, compare, repeat.
 pub struct CORDICEvaluator {
-    word_bits: u8,
     frac_bits: u8,
-    atan_table: Vec<i64>,
+    instr_table_idx: Vec<u8>,
-    gain: i64,
+    tables: Vec<CordicTable>,
 }
 
 impl CORDICEvaluator {
     pub fn new(word_bits: u8) -> Self {
         let frac_bits = word_bits - 1;
-        let iterations = word_bits;
+        CORDICEvaluator {
-
+            frac_bits,
-        // Precompute atan(2^-i) as fixed-point
+            instr_table_idx: Vec::new(),
-        let atan_table: Vec<i64> = (0..iterations)
+            tables: vec![CordicTable {
-            .map(|i| {
+                iterations: word_bits,
-                let angle = (2.0f64).powi(-(i as i32)).atan();
+                atan_table: atan_table(word_bits),
-                (angle * (1i64 << frac_bits) as f64).round() as i64
+                gain: cordic_gain(word_bits, frac_bits),
-            })
+            }],
-            .collect();
-
-        // CORDIC gain K = product of 1/sqrt(1 + 2^{-2i})
-        let mut k = 1.0f64;
-        for i in 0..iterations {
-            k *= 1.0 / (1.0 + (2.0f64).powi(-2 * i as i32)).sqrt();
         }
-        let gain = (k * (1i64 << frac_bits) as f64).round() as i64;
+    }
 
-        CORDICEvaluator { word_bits, frac_bits, atan_table, gain }
+    /// Create an evaluator from a compiled program, inheriting per-op tables.
+    pub fn from_program(program: &CORDICProgram) -> Self {
+        CORDICEvaluator {
+            frac_bits: program.word_bits - 1,
+            instr_table_idx: program.instr_table_idx.clone(),
+            tables: program.tables.clone(),
+        }
     }
 
     /// Convert f64 to fixed-point.
@@ -72,71 +73,57 @@ impl CORDICEvaluator {
         (((a as i128) << self.frac_bits) / b as i128) as i64
     }
 
-    /// CORDIC rotation mode: given angle z, compute (cos(z), sin(z)).
+    /// Resolve the table for a given instruction index.
-    /// Input z is fixed-point radians.
+    fn table_for(&self, instr_idx: usize) -> &CordicTable {
-    /// Returns (x, y) = (cos(z), sin(z)) in fixed-point.
+        if self.instr_table_idx.is_empty() || self.tables.is_empty() {
-    ///
+            // Fallback: use legacy single table via a static-lifetime trick
-    /// Algorithm:
+            // won't work — build a table reference from self fields instead
-    ///   Start with x = K (gain), y = 0, z = angle
+            return &self.tables[0];
-    ///   For each iteration i:
+        }
-    ///     if z >= 0: rotate positive (d = +1)
+        let tidx = self.instr_table_idx.get(instr_idx).copied().unwrap_or(0) as usize;
-    ///     else:      rotate negative (d = -1)
+        &self.tables[tidx.min(self.tables.len() - 1)]
-    ///     x_new = x - d * (y >> i)
+    }
-    ///     y_new = y + d * (x >> i)
+
-    ///     z_new = z - d * atan(2^-i)
+    /// CORDIC rotation mode using a specific table.
-    fn cordic_rotation(&self, angle: i64) -> (i64, i64) {
+    fn cordic_rotation_with(&self, angle: i64, table: &CordicTable) -> (i64, i64) {
-        let mut x = self.gain;
+        let mut x = table.gain;
         let mut y: i64 = 0;
         let mut z = angle;
 
-        for i in 0..self.word_bits as usize {
+        for i in 0..table.iterations as usize {
             let d = if z >= 0 { 1i64 } else { -1 };
             let x_new = x - d * (y >> i);
             let y_new = y + d * (x >> i);
-            z -= d * self.atan_table[i];
+            z -= d * table.atan_table[i];
             x = x_new;
             y = y_new;
         }
 
-        (x, y) // (cos, sin)
+        (x, y)
     }
 
-    /// CORDIC vectoring mode: given (x, y), compute magnitude and angle.
+    /// CORDIC vectoring mode using a specific table.
-    /// Returns (magnitude, angle) in fixed-point.
+    fn cordic_vectoring_with(&self, x_in: i64, y_in: i64, table: &CordicTable) -> (i64, i64) {
-    ///
-    /// Algorithm:
-    ///   Start with x, y, z = 0
-    ///   For each iteration i:
-    ///     if y < 0: rotate positive (d = +1)
-    ///     else:     rotate negative (d = -1)
-    ///     x_new = x - d * (y >> i)
-    ///     y_new = y + d * (x >> i)
-    ///     z_new = z - d * atan(2^-i)
-    ///   Result: x ≈ sqrt(x₀² + y₀²) / K, z ≈ atan2(y₀, x₀)
-    fn cordic_vectoring(&self, x_in: i64, y_in: i64) -> (i64, i64) {
         let mut x = x_in;
         let mut y = y_in;
         let mut z: i64 = 0;
 
-        // Handle negative x by reflecting into right half-plane
         let negate_x = x < 0;
         if negate_x {
             x = -x;
             y = -y;
         }
 
-        for i in 0..self.word_bits as usize {
+        for i in 0..table.iterations as usize {
             let d = if y < 0 { 1i64 } else { -1 };
             let x_new = x - d * (y >> i);
             let y_new = y + d * (x >> i);
-            z -= d * self.atan_table[i];
+            z -= d * table.atan_table[i];
             x = x_new;
             y = y_new;
         }
 
-        // Vectoring output: x_final = (1/K) * sqrt(x0^2 + y0^2).
+        let magnitude = self.fixed_mul(x, table.gain);
-        // self.gain stores K (~0.6073). Multiply to recover true magnitude.
-        let magnitude = self.fixed_mul(x, self.gain);
 
         if negate_x {
             let pi = self.to_fixed(std::f64::consts::PI);
@@ -147,10 +134,12 @@ impl CORDICEvaluator {
         }
     }
 
+
     /// Evaluate the entire trig graph using only CORDIC operations.
     /// Returns the output as f64 (converted from fixed-point at the end).
     pub fn evaluate(&self, graph: &TrigGraph, x: f64, y: f64, z: f64) -> f64 {
         let mut vals = vec![0i64; graph.nodes.len()];
+        let use_per_instr = !self.instr_table_idx.is_empty() && self.tables.len() > 1;
 
         for (i, op) in graph.nodes.iter().enumerate() {
             vals[i] = match op {
@@ -167,40 +156,44 @@ impl CORDICEvaluator {
                 TrigOp::Abs(a) => vals[*a as usize].abs(),
 
                 TrigOp::Sin(a) => {
-                    let (_, sin) = self.cordic_rotation(vals[*a as usize]);
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
+                    let (_, sin) = self.cordic_rotation_with(vals[*a as usize], t);
                     sin
                 }
                 TrigOp::Cos(a) => {
-                    let (cos, _) = self.cordic_rotation(vals[*a as usize]);
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
+                    let (cos, _) = self.cordic_rotation_with(vals[*a as usize], t);
                     cos
                 }
                 TrigOp::Tan(a) => {
-                    let (cos, sin) = self.cordic_rotation(vals[*a as usize]);
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
+                    let (cos, sin) = self.cordic_rotation_with(vals[*a as usize], t);
                     self.fixed_div(sin, cos)
                 }
                 TrigOp::Asin(a) => {
-                    // asin(x) = atan2(x, sqrt(1-x²))
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
-                    let x = vals[*a as usize];
+                    let xv = vals[*a as usize];
                     let one = self.to_fixed(1.0);
-                    let x2 = self.fixed_mul(x, x);
+                    let x2 = self.fixed_mul(xv, xv);
                     let rem = one - x2;
                     let sqrt_rem = self.fixed_sqrt(rem);
-                    let (_, angle) = self.cordic_vectoring(sqrt_rem, x);
+                    let (_, angle) = self.cordic_vectoring_with(sqrt_rem, xv, t);
                     angle
                 }
                 TrigOp::Acos(a) => {
-                    // acos(x) = atan2(sqrt(1-x²), x)
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
-                    let x = vals[*a as usize];
+                    let xv = vals[*a as usize];
                     let one = self.to_fixed(1.0);
-                    let x2 = self.fixed_mul(x, x);
+                    let x2 = self.fixed_mul(xv, xv);
                     let rem = one - x2;
                     let sqrt_rem = self.fixed_sqrt(rem);
-                    let (_, angle) = self.cordic_vectoring(x, sqrt_rem);
+                    let (_, angle) = self.cordic_vectoring_with(xv, sqrt_rem, t);
                     angle
                 }
                 TrigOp::Atan(a) => {
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
                     let one = self.to_fixed(1.0);
-                    let (_, angle) = self.cordic_vectoring(one, vals[*a as usize]);
+                    let (_, angle) = self.cordic_vectoring_with(one, vals[*a as usize], t);
                     angle
                 }
                 TrigOp::Sinh(a) => self.to_fixed(self.to_float(vals[*a as usize]).sinh()),
@@ -214,11 +207,13 @@ impl CORDICEvaluator {
                 TrigOp::Ln(a) => self.to_fixed(self.to_float(vals[*a as usize]).ln()),
 
                 TrigOp::Hypot(a, b) => {
-                    let (mag, _) = self.cordic_vectoring(vals[*a as usize], vals[*b as usize]);
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
+                    let (mag, _) = self.cordic_vectoring_with(vals[*a as usize], vals[*b as usize], t);
                     mag
                 }
                 TrigOp::Atan2(a, b) => {
-                    let (_, angle) = self.cordic_vectoring(vals[*b as usize], vals[*a as usize]);
+                    let t = if use_per_instr { self.table_for(i) } else { &self.tables[0] };
+                    let (_, angle) = self.cordic_vectoring_with(vals[*b as usize], vals[*a as usize], t);
                     angle
                 }
 
@@ -290,4 +285,47 @@ mod tests {
         assert!((cordic_val - float_val).abs() < 0.1,
             "sphere inside: CORDIC={cordic_val}, f64={float_val}");
     }
+
+    #[test]
+    fn test_per_op_config_roundtrip() {
+        use crate::config::{CordicConfig, CordicOp, CordicConfigFile, Defaults, Override};
+        use crate::compiler::CompileConfig;
+
+        let mut g = TrigGraph::new();
+        let angle = g.push(TrigOp::Const(std::f64::consts::FRAC_PI_4));
+        let s = g.push(TrigOp::Sin(angle));
+        let a = g.push(TrigOp::Const(3.0));
+        let b = g.push(TrigOp::Const(4.0));
+        let h = g.push(TrigOp::Hypot(a, b));
+        let _ = g.push(TrigOp::Add(s, h));
+        g.set_output(5);
+
+        // Config: sin at 16 iterations, hypot at 24
+        let file = CordicConfigFile {
+            defaults: Defaults { word_bits: 32, f: 32 },
+            overrides: vec![
+                Override { op: "sin".into(), f: 16 },
+                Override { op: "hypot".into(), f: 24 },
+            ],
+        };
+        let cfg = CordicConfig::from_file(&g, &file);
+        assert_eq!(cfg.iterations_for(CordicOp::Sin), 16);
+        assert_eq!(cfg.iterations_for(CordicOp::Hypot), 24);
+
+        // Compile with config
+        let compile_cfg = CompileConfig {
+            word_bits: 32,
+            cordic: Some(cfg),
+        };
+        let program = crate::CORDICProgram::compile(&g, &compile_cfg);
+        assert!(program.tables.len() >= 2);
+
+        // Evaluate from program
+        let eval = CORDICEvaluator::from_program(&program);
+        let result = eval.evaluate(&g, 0.0, 0.0, 0.0);
+
+        // Should still produce a reasonable result (sin(pi/4) + hypot(3,4) ≈ 0.707 + 5 = 5.707)
+        assert!((result - 5.707).abs() < 0.5,
+            "per-op config: result={result}, expected ~5.707");
+    }
 }

crates/cord-cordic/src/lib.rs

@@ -8,8 +8,10 @@
 //! reference is typically zero at the precision boundary.
 
 pub mod compiler;
+pub mod config;
 pub mod ops;
 pub mod eval;
 
 pub use compiler::CORDICProgram;
+pub use config::CordicConfig;
 pub use eval::CORDICEvaluator;

crates/cord-format/src/lib.rs

@@ -33,6 +33,8 @@ pub struct Layers {
     pub trig: bool,
     pub shader: bool,
     pub cordic: bool,
+    #[serde(default)]
+    pub config: bool,
 }
 
 impl Default for Manifest {
@@ -46,6 +48,7 @@ impl Default for Manifest {
                 trig: false,
                 shader: false,
                 cordic: false,
+                config: false,
             },
         }
     }

crates/cord-format/src/read.rs

@@ -66,4 +66,16 @@ impl<R: Read + Seek> ZcdReader<R> {
         }
         Ok(None)
     }
+
+    /// Read CORDIC configuration (TOML).
+    pub fn read_config(&mut self) -> Result<Option<String>> {
+        match self.archive.by_name("config/cordic.toml") {
+            Ok(mut file) => {
+                let mut buf = String::new();
+                file.read_to_string(&mut buf)?;
+                Ok(Some(buf))
+            }
+            Err(_) => Ok(None),
+        }
+    }
 }

crates/cord-format/src/write.rs

@@ -66,6 +66,15 @@ impl<W: Write + Seek> ZcdWriter<W> {
         Ok(())
     }
 
+    /// Write CORDIC configuration (TOML).
+    pub fn write_config(&mut self, config_toml: &str) -> Result<()> {
+        let options = SimpleFileOptions::default();
+        self.zip.start_file("config/cordic.toml", options)?;
+        self.zip.write_all(config_toml.as_bytes())?;
+        self.manifest.layers.config = true;
+        Ok(())
+    }
+
     pub fn finish(mut self) -> Result<W> {
         let manifest_json = serde_json::to_string_pretty(&self.manifest)?;
         let options = SimpleFileOptions::default();

src/main.rs

@@ -168,9 +168,15 @@ fn cmd_build(input: &std::path::Path, output: Option<PathBuf>, word_bits: u8) ->
     let (source, graph) = load_trig_graph(input)?;
     let wgsl = cord_shader::generate_wgsl_from_trig(&graph);
 
-    let config = cord_cordic::compiler::CompileConfig { word_bits };
+    // Auto-generate CORDIC config by scanning the graph
+    let cordic_cfg = cord_cordic::CordicConfig::scan(&graph);
+    let config = cord_cordic::compiler::CompileConfig {
+        word_bits,
+        cordic: Some(cordic_cfg.clone()),
+    };
     let cordic = cord_cordic::CORDICProgram::compile(&graph, &config);
     let cordic_bytes = cordic.to_bytes();
+    let config_toml = cordic_cfg.to_toml();
 
     let file = std::fs::File::create(&out_path)
         .with_context(|| format!("creating {}", out_path.display()))?;
@@ -187,6 +193,7 @@ fn cmd_build(input: &std::path::Path, output: Option<PathBuf>, word_bits: u8) ->
     }
     writer.write_shader(&wgsl)?;
     writer.write_cordic(&cordic_bytes, word_bits)?;
+    writer.write_config(&config_toml)?;
     writer.finish()?;
 
     println!("wrote {}", out_path.display());
@@ -236,7 +243,11 @@ fn cmd_decompile(
     let graph = cord_sdf::sdf_to_trig(&result.sdf);
     let wgsl = cord_shader::generate_wgsl_from_trig(&graph);
 
-    let cordic_config = cord_cordic::compiler::CompileConfig { word_bits };
+    let cordic_cfg = cord_cordic::CordicConfig::scan(&graph);
+    let cordic_config = cord_cordic::compiler::CompileConfig {
+        word_bits,
+        cordic: Some(cordic_cfg),
+    };
     let cordic = cord_cordic::CORDICProgram::compile(&graph, &cordic_config);
     let cordic_bytes = cordic.to_bytes();