Clarify masking of bits in Field::random impls

Co-Authored-By: Daira Hopwood <[email protected]>
5 years ago · 0255dca16e
2 changed files with 2 additions and 2 deletions
--- a/ff/ff_derive/src/lib.rs
+++ b/ff/ff_derive/src/lib.rs
@ -892,7 +892,7 @@ fn prime_field_impl(
                        #name(#repr(repr))
                    };

-                    // Mask away the unused bits at the beginning.
+                    // Mask away the unused most-significant bits.
                    tmp.0.as_mut()[#top_limb_index] &= 0xffffffffffffffff >> REPR_SHAVE_BITS;

                    if tmp.is_valid() {
--- a/sapling-crypto/src/jubjub/fs.rs
+++ b/sapling-crypto/src/jubjub/fs.rs
@ -292,7 +292,7 @@ impl Field for Fs {
                Fs(FsRepr(repr))
            };

-            // Mask away the unused bits at the beginning.
+            // Mask away the unused most-significant bits.
            tmp.0.as_mut()[3] &= 0xffffffffffffffff >> REPR_SHAVE_BITS;

            if tmp.is_valid() {