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authorJack Lloyd <[email protected]>2018-04-16 07:18:34 -0400
committerJack Lloyd <[email protected]>2018-04-16 07:18:34 -0400
commitc620c61cf5e9379a074a1ff8fa9fa913c27dd5eb (patch)
treec44e88542cf3b57dd0a6d8a8e624f3096d689f1f /src/lib/math
parent173fb17e576a76a0a9f4d0fc5933ec2876ee638f (diff)
Add vars to split the two Karatsuba sub-workspaces
Diffstat (limited to 'src/lib/math')
-rw-r--r--src/lib/math/mp/mp_karat.cpp34
1 files changed, 20 insertions, 14 deletions
diff --git a/src/lib/math/mp/mp_karat.cpp b/src/lib/math/mp/mp_karat.cpp
index 2ac03ac1e..220bd8f9e 100644
--- a/src/lib/math/mp/mp_karat.cpp
+++ b/src/lib/math/mp/mp_karat.cpp
@@ -101,6 +101,9 @@ void karatsuba_mul(word z[], const word x[], const word y[], size_t N,
word* z0 = z;
word* z1 = z + N;
+ word* ws0 = workspace;
+ word* ws1 = workspace + N;
+
clear_mem(workspace, 2*N);
/*
@@ -116,25 +119,25 @@ void karatsuba_mul(word z[], const word x[], const word y[], size_t N,
const int32_t cmp0 = bigint_sub_abs(z0, x0, x1, N2);
const int32_t cmp1 = bigint_sub_abs(z1, y1, y0, N2);
- karatsuba_mul(workspace, z0, z1, N2, workspace+N);
+ karatsuba_mul(ws0, z0, z1, N2, ws1);
const bool is_negative = cmp0 != cmp1;
// Compute X_lo * Y_lo
- karatsuba_mul(z0, x0, y0, N2, workspace+N);
+ karatsuba_mul(z0, x0, y0, N2, ws1);
// Compute X_hi * Y_hi
- karatsuba_mul(z1, x1, y1, N2, workspace+N);
+ karatsuba_mul(z1, x1, y1, N2, ws1);
- const word ws_carry = bigint_add3_nc(workspace + N, z0, N, z1, N);
- word z_carry = bigint_add2_nc(z + N2, N, workspace + N, N);
+ const word ws_carry = bigint_add3_nc(ws1, z0, N, z1, N);
+ word z_carry = bigint_add2_nc(z + N2, N, ws1, N);
z_carry += bigint_add2_nc(z + N + N2, N2, &ws_carry, 1);
bigint_add2_nc(z + N + N2, N2, &z_carry, 1);
if(is_negative)
- bigint_sub2(z + N2, 2*N-N2, workspace, N);
+ bigint_sub2(z + N2, 2*N-N2, ws0, N);
else
- bigint_add2_nc(z + N2, 2*N-N2, workspace, N);
+ bigint_add2_nc(z + N2, 2*N-N2, ws0, N);
}
/*
@@ -161,27 +164,30 @@ void karatsuba_sqr(word z[], const word x[], size_t N, word workspace[])
word* z0 = z;
word* z1 = z + N;
+ word* ws0 = workspace;
+ word* ws1 = workspace + N;
+
clear_mem(workspace, 2*N);
// See comment in karatsuba_mul
bigint_sub_abs(z0, x0, x1, N2);
- karatsuba_sqr(workspace, z0, N2, workspace+N);
+ karatsuba_sqr(ws0, z0, N2, ws1);
- karatsuba_sqr(z0, x0, N2, workspace+N);
- karatsuba_sqr(z1, x1, N2, workspace+N);
+ karatsuba_sqr(z0, x0, N2, ws1);
+ karatsuba_sqr(z1, x1, N2, ws1);
- const word ws_carry = bigint_add3_nc(workspace + N, z0, N, z1, N);
- word z_carry = bigint_add2_nc(z + N2, N, workspace + N, N);
+ const word ws_carry = bigint_add3_nc(ws1, z0, N, z1, N);
+ word z_carry = bigint_add2_nc(z + N2, N, ws1, N);
z_carry += bigint_add2_nc(z + N + N2, N2, &ws_carry, 1);
bigint_add2_nc(z + N + N2, N2, &z_carry, 1);
/*
* This is only actually required if cmp (result of bigint_sub_abs) is != 0,
- * however if cmp==0 then workspace[0:N] == 0 and avoiding the jump hides a
+ * however if cmp==0 then ws0[0:N] == 0 and avoiding the jump hides a
* timing channel.
*/
- bigint_sub2(z + N2, 2*N-N2, workspace, N);
+ bigint_sub2(z + N2, 2*N-N2, ws0, N);
}
/*