From 147b9d90b8849862cc70c913eb9022c07a74a571 Mon Sep 17 00:00:00 2001 From: Henry de Valence Date: Sun, 12 Mar 2017 23:18:40 -0700 Subject: [PATCH] Revert "Add radix51 impl of reduce" This reverts commit 488e886d1e1b11400dedc6c41e7108e34c6747cc. --- src/field.rs | 34 ---------------------------------- 1 file changed, 34 deletions(-) diff --git a/src/field.rs b/src/field.rs index cb729b8..166d604 100644 --- a/src/field.rs +++ b/src/field.rs @@ -415,40 +415,6 @@ impl FieldElement { output[9] = h[9] as i32; output } - #[cfg(feature="radix_51")] - fn reduce(input: &[u128; 5]) -> FieldElement { - // After multiplication, - // c[i] < 2^2b * (1+i + (4-i)*19) < 2^(2b + lg(1+4*19)) < 2^(2b + 6.27) - // where b is the bitlength of the input limbs. - - // The carry (c[i] >> 51) fits into a u64 iff 2b+6.27 < 64+51 iff b <= 54. - // After the first carry pass, all c[i] fit into u64. - - let low_51_bit_mask = (1u64 << 51) - 1; - c1 += (c0 >> 51) as u128; - let mut c0: u64 = (c0 as u64) & low_51_bit_mask; - c2 += (c1 >> 51) as u128; - let mut c1: u64 = (c1 as u64) & low_51_bit_mask; - c3 += (c2 >> 51) as u128; - let mut c2: u64 = (c2 as u64) & low_51_bit_mask; - c4 += (c3 >> 51) as u128; - let mut c3: u64 = (c3 as u64) & low_51_bit_mask; - c0 += ((c4 >> 51) as u64) * 19; - let mut c4: u64 = (c4 as u64) & low_51_bit_mask; - - c1 += c0 >> 51; - c0 = c0 & low_51_bit_mask; - c2 += c1 >> 51; - c1 = c1 & low_51_bit_mask; - c3 += c2 >> 51; - c2 = c2 & low_51_bit_mask; - c4 += c3 >> 51; - c3 = c3 & low_51_bit_mask; - c0 += (c4 >> 51) * 19; - c4 = c4 & low_51_bit_mask; - - FieldElement([c0,c1,c2,c3,c4]) - } /// Create a FieldElement by demarshalling an array of 32 bytes. ///