circuit::gadget: Remove Orchard-specific names from gadget consts.

- L_ORCHARD_BASE -> pallas::Base::NUM_BITS,
- L_ORCHARD_SCALAR -> pallas::Scalar::NUM_BITS,
- L_VALUE -> L_SCALAR_SHORT,
- MERKLE_DEPTH_ORCHARD -> MERKLE_DEPTH.

src/circuit/gadget/ecc/chip.rs

@@ -6,6 +6,7 @@ use crate::{
     primitives::sinsemilla,
 };
 use arrayvec::ArrayVec;
+use ff::PrimeField;
 
 use ff::Field;
 use group::prime::PrimeCurveAffine;
@@ -31,23 +32,15 @@ pub const H: usize = 1 << FIXED_BASE_WINDOW_SIZE;
 
 /// Number of windows for a full-width scalar
 pub const NUM_WINDOWS: usize =
-    (L_ORCHARD_SCALAR + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
+    (pallas::Scalar::NUM_BITS as usize + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
 
 /// Number of windows for a short signed scalar
 pub const NUM_WINDOWS_SHORT: usize =
-    (L_VALUE + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
+    (L_SCALAR_SHORT + FIXED_BASE_WINDOW_SIZE - 1) / FIXED_BASE_WINDOW_SIZE;
 
 /// $\ell_\mathsf{value}$
 /// Number of bits in an unsigned short scalar.
-pub(crate) const L_VALUE: usize = 64;
+pub(crate) const L_SCALAR_SHORT: usize = 64;
-
-/// $\ell^\mathsf{Orchard}_\mathsf{base}$
-/// Number of bits in a Pallas base field element.
-pub(crate) const L_ORCHARD_BASE: usize = 255;
-
-/// $\ell^\mathsf{Orchard}_\mathsf{scalar}$
-/// Number of bits in a Pallas scalar field element.
-pub(crate) const L_ORCHARD_SCALAR: usize = 255;
 
 /// The Pallas scalar field modulus is $q = 2^{254} + \mathsf{t_q}$.
 /// <https://github.com/zcash/pasta>

src/circuit/gadget/ecc/chip/mul_fixed/base_field_elem.rs

@@ -1,6 +1,4 @@
-use super::super::{
+use super::super::{EccBaseFieldElemFixed, EccPoint, FixedPoints, NUM_WINDOWS, T_P};
-    EccBaseFieldElemFixed, EccPoint, FixedPoints, L_ORCHARD_BASE, NUM_WINDOWS, T_P,
-};
 use super::H_BASE;
 
 use crate::{
@@ -9,9 +7,10 @@ use crate::{
     },
     primitives::sinsemilla,
 };
-use halo2::circuit::AssignedCell;
+
+use group::ff::PrimeField;
 use halo2::{
-    circuit::Layouter,
+    circuit::{AssignedCell, Layouter},
     plonk::{Advice, Column, ConstraintSystem, Error, Expression, Selector},
     poly::Rotation,
 };
@@ -179,7 +178,7 @@ impl<Fixed: FixedPoints<pallas::Affine>> Config<Fixed> {
                         offset,
                         scalar.clone(),
                         true,
-                        L_ORCHARD_BASE,
+                        pallas::Base::NUM_BITS as usize,
                         NUM_WINDOWS,
                     )?;
                     EccBaseFieldElemFixed {
@@ -217,7 +216,7 @@ impl<Fixed: FixedPoints<pallas::Affine>> Config<Fixed> {
         // Check that the correct multiple is obtained.
         {
             use super::super::FixedPoint;
-            use group::{ff::PrimeField, Curve};
+            use group::Curve;
 
             let scalar = &scalar
                 .base_field_elem()

src/circuit/gadget/ecc/chip/mul_fixed/full_width.rs

@@ -1,9 +1,8 @@
-use super::super::{
+use super::super::{EccPoint, EccScalarFixed, FixedPoints, FIXED_BASE_WINDOW_SIZE, H, NUM_WINDOWS};
-    EccPoint, EccScalarFixed, FixedPoints, FIXED_BASE_WINDOW_SIZE, H, L_ORCHARD_SCALAR, NUM_WINDOWS,
-};
 
 use crate::circuit::gadget::utilities::{decompose_word, range_check};
 use arrayvec::ArrayVec;
+use ff::PrimeField;
 use halo2::{
     circuit::{AssignedCell, Layouter, Region},
     plonk::{ConstraintSystem, Error, Selector},
@@ -59,7 +58,9 @@ impl<Fixed: FixedPoints<pallas::Affine>> Config<Fixed> {
         offset: usize,
         scalar: Option<pallas::Scalar>,
     ) -> Result<EccScalarFixed, Error> {
-        let windows = self.decompose_scalar_fixed::<L_ORCHARD_SCALAR>(scalar, offset, region)?;
+        let windows = self.decompose_scalar_fixed::<{ pallas::Scalar::NUM_BITS as usize }>(
+            scalar, offset, region,
+        )?;
 
         Ok(EccScalarFixed {
             value: scalar,

src/circuit/gadget/ecc/chip/mul_fixed/short.rs

@@ -1,6 +1,6 @@
 use std::{array, convert::TryInto};
 
-use super::super::{EccPoint, EccScalarFixedShort, FixedPoints, L_VALUE, NUM_WINDOWS_SHORT};
+use super::super::{EccPoint, EccScalarFixedShort, FixedPoints, L_SCALAR_SHORT, NUM_WINDOWS_SHORT};
 use crate::circuit::gadget::{ecc::chip::MagnitudeSign, utilities::bool_check};
 
 use halo2::{
@@ -81,7 +81,7 @@ impl<Fixed: FixedPoints<pallas::Affine>> Config<Fixed> {
             offset,
             magnitude.clone(),
             true,
-            L_VALUE,
+            L_SCALAR_SHORT,
             NUM_WINDOWS_SHORT,
         )?;
 

src/circuit/gadget/sinsemilla.rs

@@ -546,7 +546,7 @@ mod tests {
                     &OrchardHashDomains::MerkleCrh,
                 );
 
-                // Layer 31, l = MERKLE_DEPTH_ORCHARD - 1 - layer = 0
+                // Layer 31, l = MERKLE_DEPTH - 1 - layer = 0
                 let l_bitstring = vec![Some(false); K];
                 let l = MessagePiece::from_bitstring(
                     chip1.clone(),

src/circuit/gadget/sinsemilla/merkle.rs

@@ -16,12 +16,8 @@ pub(in crate::circuit) mod chip;
 /// SWU hash-to-curve personalization for the Merkle CRH generator
 pub const MERKLE_CRH_PERSONALIZATION: &str = "z.cash:Orchard-MerkleCRH";
 
-/// $\mathsf{MerkleDepth^{Orchard}}$
+/// Depth of Merkle tree
-pub(crate) const MERKLE_DEPTH_ORCHARD: usize = 32;
+pub(crate) const MERKLE_DEPTH: usize = 32;
-
-/// $\ell^\mathsf{Orchard}_\mathsf{base}$
-/// Number of bits in a Pallas base field element.
-pub(crate) const L_ORCHARD_BASE: usize = 255;
 
 /// Instructions to check the validity of a Merkle path of a given `PATH_LENGTH`.
 /// The hash function used is a Sinsemilla instance with `K`-bit words.
@@ -39,7 +35,7 @@ pub trait MerkleInstructions<
 {
     /// Compute MerkleCRH for a given `layer`. The hash that computes the root
     /// is at layer 0, and the hashes that are applied to two leaves are at
-    /// layer `MERKLE_DEPTH_ORCHARD - 1` = layer 31.
+    /// layer `MERKLE_DEPTH - 1` = layer 31.
     #[allow(non_snake_case)]
     fn hash_layer(
         &self,
@@ -107,7 +103,7 @@ where
 
         let mut node = leaf;
         for (l, ((sibling, pos), chip)) in path.iter().zip(pos.iter()).zip(chips).enumerate() {
-            // `l` = MERKLE_DEPTH_ORCHARD - layer - 1, which is the index obtained from
+            // `l` = MERKLE_DEPTH - layer - 1, which is the index obtained from
             // enumerating this Merkle path (going from leaf to root).
             // For example, when `layer = 31` (the first sibling on the Merkle path),
             // we have `l` = 32 - 31 - 1 = 0.
@@ -140,7 +136,7 @@ where
 pub mod tests {
     use super::{
         chip::{MerkleChip, MerkleConfig},
-        MerklePath, MERKLE_DEPTH_ORCHARD,
+        MerklePath, MERKLE_DEPTH,
     };
 
     use crate::{
@@ -168,7 +164,7 @@ pub mod tests {
     struct MyCircuit {
         leaf: Option<pallas::Base>,
         leaf_pos: Option<u32>,
-        merkle_path: Option<[pallas::Base; MERKLE_DEPTH_ORCHARD]>,
+        merkle_path: Option<[pallas::Base; MERKLE_DEPTH]>,
     }
 
     impl Circuit<pallas::Base> for MyCircuit {
@@ -295,7 +291,7 @@ pub mod tests {
         let pos = rng.next_u32();
 
         // Choose a path of random inner nodes
-        let path: Vec<_> = (0..(MERKLE_DEPTH_ORCHARD))
+        let path: Vec<_> = (0..(MERKLE_DEPTH))
             .map(|_| pallas::Base::random(rng))
             .collect();
 

src/circuit/gadget/sinsemilla/merkle/chip.rs

@@ -5,7 +5,7 @@ use halo2::{
 };
 use pasta_curves::{arithmetic::FieldExt, pallas};
 
-use super::{MerkleInstructions, L_ORCHARD_BASE, MERKLE_DEPTH_ORCHARD};
+use super::{MerkleInstructions, MERKLE_DEPTH};
 
 use crate::{
     circuit::gadget::{
@@ -22,6 +22,7 @@ use crate::{
     },
     primitives::sinsemilla,
 };
+use group::ff::PrimeField;
 use std::array;
 
 #[derive(Clone, Debug)]
@@ -180,7 +181,7 @@ where
 }
 
 impl<Hash, Commit, F>
-    MerkleInstructions<pallas::Affine, MERKLE_DEPTH_ORCHARD, { sinsemilla::K }, { sinsemilla::C }>
+    MerkleInstructions<pallas::Affine, MERKLE_DEPTH, { sinsemilla::K }, { sinsemilla::C }>
     for MerkleChip<Hash, Commit, F>
 where
     Hash: HashDomains<pallas::Affine>,
@@ -192,7 +193,7 @@ where
         &self,
         mut layouter: impl Layouter<pallas::Base>,
         Q: pallas::Affine,
-        // l = MERKLE_DEPTH_ORCHARD - layer - 1
+        // l = MERKLE_DEPTH - layer - 1
         l: usize,
         left: Self::Var,
         right: Self::Var,
@@ -234,7 +235,7 @@ where
             let b_1 = {
                 let b_1 = left
                     .value()
-                    .map(|value| bitrange_subset(value, 250..L_ORCHARD_BASE));
+                    .map(|value| bitrange_subset(value, 250..(pallas::Base::NUM_BITS as usize)));
 
                 config
                     .sinsemilla_config
@@ -274,7 +275,7 @@ where
             // `c = bits 5..=254 of `right`
             let c = right
                 .value()
-                .map(|value| bitrange_subset(value, 5..L_ORCHARD_BASE));
+                .map(|value| bitrange_subset(value, 5..(pallas::Base::NUM_BITS as usize)));
             self.witness_message_piece(layouter.namespace(|| "Witness c"), c, 25)?
         };
 
@@ -299,7 +300,7 @@ where
                 || "Check piece decomposition",
                 |mut region| {
                     // Set the fixed column `l` to the current l.
-                    // Recall that l = MERKLE_DEPTH_ORCHARD - layer - 1.
+                    // Recall that l = MERKLE_DEPTH - layer - 1.
                     // The layer with 2^n nodes is called "layer n".
                     config.q_decompose.enable(&mut region, 0)?;
                     region.assign_advice_from_constant(
@@ -346,7 +347,7 @@ where
         {
             use super::MERKLE_CRH_PERSONALIZATION;
             use crate::{primitives::sinsemilla::HashDomain, spec::i2lebsp};
-            use group::ff::{PrimeField, PrimeFieldBits};
+            use group::ff::PrimeFieldBits;
 
             if let (Some(left), Some(right)) = (left.value(), right.value()) {
                 let l = i2lebsp::<10>(l as u64);
@@ -354,13 +355,13 @@ where
                     .to_le_bits()
                     .iter()
                     .by_val()
-                    .take(L_ORCHARD_BASE)
+                    .take(pallas::Base::NUM_BITS as usize)
                     .collect();
                 let right: Vec<_> = right
                     .to_le_bits()
                     .iter()
                     .by_val()
-                    .take(L_ORCHARD_BASE)
+                    .take(pallas::Base::NUM_BITS as usize)
                     .collect();
                 let merkle_crh = HashDomain::new(MERKLE_CRH_PERSONALIZATION);