instantiate only for desired limbs

Author: jon-chuang

ff/src/fields/models/fp.rs

@@ -15,10 +15,10 @@ use crate::{
 };
 use ark_serialize::*;
 
-invoke_16!(impl_field_square_in_place);
-invoke_16!(impl_field_mul_assign);
+invoke_n!(impl_field_square_in_place);
+invoke_n!(impl_field_mul_assign);
 
-pub trait FpParams<const N: usize>: FpParameters<N, BigInt = BigInt<N>> {
+pub trait FpParams<const N: usize>: FpParameters<BigInt = BigInt<N>> {
     // Checking the modulus at compile time
     const NO_CARRY: bool = {
         let first_bit_set = Self::MODULUS.0[N - 1] >> 63 != 0;
@@ -87,7 +87,7 @@ impl<P, const N: usize> Fp<P, N> {
         modulus: BigInt<N>,
         inv: u64,
     ) -> Self {
-        let mut repr = P::BigInt([0; N]);
+        let mut repr = BigInt::<N>([0; N]);
         let mut i = 0;
         while i < limbs.len() {
             repr.0[i] = limbs[i];

ff/src/fields/models/mod.rs

@@ -1,51 +1,32 @@
-#[macro_export]
-macro_rules! match_const {
-    ($fn_name:ident, $N:expr $(, $args:tt)*) => {
-        paste::paste! {
-            match $N {
-                1 => [<$fn_name _ id1>]($($args),*),
-                2 => [<$fn_name _ id2>]($($args),*),
-                3 => [<$fn_name _ id3>]($($args),*),
-                4 => [<$fn_name _ id4>]($($args),*),
-                5 => [<$fn_name _ id5>]($($args),*),
-                6 => [<$fn_name _ id6>]($($args),*),
-                7 => [<$fn_name _ id7>]($($args),*),
-                8 => [<$fn_name _ id8>]($($args),*),
-                9 => [<$fn_name _ id9>]($($args),*),
-                10 => [<$fn_name _ id10>]($($args),*),
-                11 => [<$fn_name _ id11>]($($args),*),
-                12 => [<$fn_name _ id12>]($($args),*),
-                13 => [<$fn_name _ id13>]($($args),*),
-                14 => [<$fn_name _ id14>]($($args),*),
-                15 => [<$fn_name _ id15>]($($args),*),
-                16 => [<$fn_name _ id16>]($($args),*),
-                _ => unreachable!(),
+macro_rules! limb_instantiation {
+    ($($ns:expr),*) => {
+        macro_rules! make_nested_macro {
+            ($d:tt) => {
+                macro_rules! match_const {
+                    ($fn_name:ident, $N:expr $d(, $d args:tt)*) => {
+                        paste::paste! {
+                            match $N {
+                                $($ns => [<$fn_name _ id$ns>]::<P, N>($d($d args),*),)*
+                                _ => unreachable!(),
+                            };
+                        }
+                    };
+                }
             };
         }
-    };
-}
 
-macro_rules! invoke_16 {
-    ($macro_name:ident) => {
-        $macro_name!(1);
-        $macro_name!(2);
-        $macro_name!(3);
-        $macro_name!(4);
-        $macro_name!(5);
-        $macro_name!(6);
-        $macro_name!(7);
-        $macro_name!(8);
-        $macro_name!(9);
-        $macro_name!(10);
-        $macro_name!(11);
-        $macro_name!(12);
-        $macro_name!(13);
-        $macro_name!(14);
-        $macro_name!(15);
-        $macro_name!(16);
-    };
+        make_nested_macro!($);
+
+        macro_rules! invoke_n {
+            ($macro_name:ident) => {
+                $($macro_name!($ns);)*
+            };
+        }
+    }
 }
 
+limb_instantiation!(1, 4, 5, 6, 12, 13);
+
 pub mod fp;
 pub use self::fp::*;