diff options
Diffstat (limited to 'plugins/ioam-plugin/ioam/lib-pot/math64.h')
-rw-r--r-- | plugins/ioam-plugin/ioam/lib-pot/math64.h | 159 |
1 files changed, 0 insertions, 159 deletions
diff --git a/plugins/ioam-plugin/ioam/lib-pot/math64.h b/plugins/ioam-plugin/ioam/lib-pot/math64.h deleted file mode 100644 index 4c608a37de4..00000000000 --- a/plugins/ioam-plugin/ioam/lib-pot/math64.h +++ /dev/null @@ -1,159 +0,0 @@ -/* - * math64.h provides the 64 bit unsigned integer add, multiply followed by modulo operation - * The linux/math64.h provides divide and multiply 64 bit integers but: - * 1. multiply: mul_u64_u64_shr - only returns 64 bits of the result and has to be called - * twice to get the complete 128 bits of the result. - * 2. Modulo operation of the result of addition and multiplication of u64 that may result - * in integers > 64 bits is not supported - * Hence this header to combine add/multiply followed by modulo of u64 integrers - * always resulting in u64. - * - * Copyright (c) 2016 Cisco and/or its affiliates. - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at: - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ -#ifndef include_vnet_math64_h -#define include_vnet_math64_h -#include <stdint.h> - -/* - * multiplies and returns result in hi and lo - */ -static inline void mul64by64(u64 a, u64 b, u64 * hi, u64 * lo) -{ - u64 a_lo = (u64) (uint32_t) a; - u64 a_hi = a >> 32; - u64 b_lo = (u64) (u32) b; - u64 b_hi = b >> 32; - - u64 p0 = a_lo * b_lo; - u64 p1 = a_lo * b_hi; - u64 p2 = a_hi * b_lo; - u64 p3 = a_hi * b_hi; - - u32 cy = (u32) (((p0 >> 32) + (u32) p1 + (u32) p2) >> 32); - - *lo = p0 + (p1 << 32) + (p2 << 32); - *hi = p3 + (p1 >> 32) + (p2 >> 32) + cy; - return; -} - -#define TWO64 18446744073709551616.0 - -static inline u64 mod128by64(u64 x, u64 y, u64 m, double di) -{ - u64 q1, q2, q; - u64 p1, p0; - double dq; - - /* calculate quotient first pass 53 bits */ - dq = (TWO64 * (double)x + (double)y) * di; - - if (dq >= TWO64) - q1 = 0xfffffffffffff800L; - else - q1 = dq; - - /* q1 * m to compare the product to the dividend. */ - mul64by64(q1, m, &p1, &p0); - - /* Adjust quotient. is it > actual result: */ - if (x < p1 || (x == p1 && y < p0)) - { - /* q1 > quotient. calculate abs remainder */ - x = p1 - (x + (p0 < y)); - y = p0 - y; - - /* use the remainder as new dividend to adjust quotient */ - q2 = (u64) ((TWO64 * (double)x + (double)y) * di); - mul64by64(q2, m, &p1, &p0); - - q = q1 - q2; - if (x < p1 || (x == p1 && y <= p0)) - { - y = p0 - y; - } - else - { - y = p0 - y; - y += m; - q--; - } - } - else - { - x = x - (p1 + (y < p0)); - y = y - p0; - - q2 = (u64) ((TWO64 * (double)x + (double)y) * di); - mul64by64(q2, m, &p1, &p0); - - q = q1 + q2; - if (x < p1 || (x == p1 && y < p0)) - { - y = y - p0; - y += m; - q--; - } - else - { - y = y - p0; - if (y >= m) - { - y -= m; - q++; - } - } - } - - return y; -} - -/* - * returns a % p - */ -static inline u64 mod64by64(u64 a, u64 p, u64 primeinv) -{ - return (mod128by64(0, a, p, primeinv)); -} - -static inline void add64(u64 a, u64 b, u64 * whi, u64 * wlo) -{ - *wlo = a + b; - if (*wlo < a) - *whi = 1; - -} - -/* - * returns (a + b)%p - */ -static inline u64 add64_mod(u64 a, u64 b, u64 p, double pi) -{ - u64 shi = 0, slo = 0; - - add64(a, b, &shi, &slo); - return (mod128by64(shi, slo, p, pi)); -} - -/* - * returns (ab) % p - */ -static inline u64 mul64_mod(u64 a, u64 b, u64 p, double pi) -{ - u64 phi = 0, plo = 0; - - mul64by64(a, b, &phi, &plo); - return (mod128by64(phi, plo, p, pi)); -} - -#endif |