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Diffstat (limited to 'libj2_j2u_mul_ju.c')
| -rw-r--r-- | libj2_j2u_mul_ju.c | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/libj2_j2u_mul_ju.c b/libj2_j2u_mul_ju.c new file mode 100644 index 0000000..17fc453 --- /dev/null +++ b/libj2_j2u_mul_ju.c @@ -0,0 +1,197 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" +#ifndef TEST + +extern inline void libj2_j2u_mul_ju(struct libj2_j2u *a, uintmax_t b); +/* TODO Add man page */ + + +#else + +static uintmax_t +random_small_ju(size_t bits) +{ + uintmax_t r = 0; + while (bits--) + if (rand() < rand()) + r |= (uintmax_t)1 << bits; + return r; +} + +static uintmax_t +random_hju(void) +{ + return random_small_ju(LIBJ2_JU_BIT / 2U); +} + +static uintmax_t +random_ju(void) +{ + return random_small_ju(LIBJ2_JU_BIT); +} + + +static int +refmul(const struct libj2_j2u *a, uintmax_t b, struct libj2_j2u *expected) +{ + struct libj2_j2u c; + unsigned i; + int overflow = 0; + + libj2_j2u_zero(expected); + for (i = 0; i < LIBJ2_J2U_BIT; i++, b >>= 1) { + if (b & 1U) { + overflow |= libj2_j2u_lsh_to_j2u_overflow(a, i, &c); + libj2_j2u_add_j2u(expected, &c); + } + } + + return overflow; +} + + +static void +mul(const struct libj2_j2u *a, uintmax_t b, struct libj2_j2u *expected, int expect_overflow) +{ + struct libj2_j2u t, a_saved = *a; + + *expected = *a; + libj2_j2u_mul_ju(expected, b); + + t = (struct libj2_j2u){111, 222}; + libj2_j2u_mul_ju_to_j2u(a, b, &t); + EXPECT(libj2_j2u_eq_j2u(&t, expected)); + EXPECT(libj2_j2u_eq_j2u(a, &a_saved)); + + t = (struct libj2_j2u){111, 222}; + libj2_ju_mul_j2u_to_j2u(b, a, &t); + EXPECT(libj2_j2u_eq_j2u(&t, expected)); + EXPECT(libj2_j2u_eq_j2u(a, &a_saved)); + + t = *a; + EXPECT(libj2_j2u_mul_ju_overflow(&t, b) == expect_overflow); + EXPECT(libj2_j2u_eq_j2u(&t, expected)); + + t = (struct libj2_j2u){111, 222}; + EXPECT(libj2_j2u_mul_ju_to_j2u_overflow(a, b, &t) == expect_overflow); + EXPECT(libj2_j2u_eq_j2u(&t, expected)); + EXPECT(libj2_j2u_eq_j2u(a, &a_saved)); + + t = (struct libj2_j2u){111, 222}; + EXPECT(libj2_ju_mul_j2u_to_j2u_overflow(b, a, &t) == expect_overflow); + EXPECT(libj2_j2u_eq_j2u(&t, expected)); + EXPECT(libj2_j2u_eq_j2u(a, &a_saved)); +} + + +int +main(void) +{ + struct libj2_j2u r, expected; + uintmax_t u, v, w; + unsigned i; + int expect_overflow; + + srand((unsigned)time(NULL)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 0}, 0, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 0}, 1, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 0}, UINTMAX_MAX, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 1}, 0, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = UINTMAX_MAX}, 0, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + for (i = 0; i < 32; i++) { + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 0}, random_ju(), &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = random_ju()}, 0, &r, 0); + EXPECT(libj2_j2u_is_zero(&r)); + } + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 1}, 1, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == 1); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = 4}, 4, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == 16); + + for (i = 0; i < 32; i++) { + r = (struct libj2_j2u){111, 222}; + v = random_ju(); + mul(&(struct libj2_j2u){.high = 0, .low = 1}, v, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == v); + + r = (struct libj2_j2u){111, 222}; + v = random_ju(); + mul(&(struct libj2_j2u){.high = 0, .low = v}, 1, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == v); + } + + for (i = 0; i < 32; i++) { + u = random_hju(); + v = random_hju(); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = u}, v, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == u * v); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = v}, u, &r, 0); + EXPECT(r.high == 0); + EXPECT(r.low == u * v); + } + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = 0, .low = UINTMAX_MAX}, UINTMAX_MAX, &r, 0); + EXPECT(r.high == UINTMAX_MAX - 1U); + EXPECT(r.low == 1); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){.high = UINTMAX_MAX, .low = UINTMAX_MAX}, UINTMAX_MAX, &r, 1); + EXPECT(r.high == UINTMAX_MAX); + EXPECT(r.low == 1); + + /* self-check */ + r = (struct libj2_j2u){111, 222}; + EXPECT(refmul(&(struct libj2_j2u){.high = UINTMAX_MAX, .low = UINTMAX_MAX}, UINTMAX_MAX, &r) == 1); + EXPECT(r.high == UINTMAX_MAX); + EXPECT(r.low == 1); + + for (i = 0; i < 256; i++) { + u = random_ju(); + v = random_ju(); + w = random_ju(); + + expect_overflow = refmul(&(struct libj2_j2u){u, v}, w, &expected); + + r = (struct libj2_j2u){111, 222}; + mul(&(struct libj2_j2u){u, v}, w, &r, expect_overflow); + EXPECT(libj2_j2u_eq_j2u(&r, &expected)); + } + + return 0; +} + +#endif |