diff options
Diffstat (limited to 'libj2_j2u_add_j2u.c')
| -rw-r--r-- | libj2_j2u_add_j2u.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/libj2_j2u_add_j2u.c b/libj2_j2u_add_j2u.c new file mode 100644 index 0000000..bd783a0 --- /dev/null +++ b/libj2_j2u_add_j2u.c @@ -0,0 +1,201 @@ +/* See LICENSE file for copyright and license details. */ +#include "common.h" +#ifndef TEST + +extern inline void libj2_j2u_add_j2u(struct libj2_j2u *a, const struct libj2_j2u *b); +/* TODO Add man page */ + + +#else + +static uintmax_t +random_ju(void) +{ + size_t n = LIBJ2_JU_BIT; + uintmax_t r = 0; + while (n--) + if (rand() < rand()) + r |= (uintmax_t)1 << n; + return r; +} + + +static void +check_(uintmax_t a_high, uintmax_t a_low, uintmax_t b_high, uintmax_t b_low, + uintmax_t r_high, uintmax_t r_low, int r_overflow) +{ + struct libj2_j2u a, b, r, a_saved, b_saved, expected; + + a_saved = (struct libj2_j2u){.high = a_high, .low = a_low}; + b_saved = (struct libj2_j2u){.high = b_high, .low = b_low}; + expected = (struct libj2_j2u){.high = r_high, .low = r_low}; + + a = a_saved; + b = b_saved; + libj2_j2u_add_j2u(&a, &b); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + b = b_saved; + libj2_j2u_add_j2u_to_j2u(&a, &b, &r); + EXPECT(libj2_j2u_eq_j2u(&r, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + a = a_saved; + b = b_saved; + libj2_j2u_add_j2u_to_j2u(&a, &b, &a); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + a = a_saved; + b = b_saved; + libj2_j2u_add_j2u_to_j2u(&a, &b, &b); + EXPECT(libj2_j2u_eq_j2u(&b, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + b = b_saved; + EXPECT(libj2_j2u_add_j2u_overflow(&a, &b) == r_overflow); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + b = b_saved; + EXPECT(libj2_j2u_add_j2u_to_j2u_overflow(&a, &b, &r) == r_overflow); + EXPECT(libj2_j2u_eq_j2u(&r, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + a = a_saved; + b = b_saved; + EXPECT(libj2_j2u_add_j2u_to_j2u_overflow(&a, &b, &a) == r_overflow); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + EXPECT(libj2_j2u_eq_j2u(&b, &b_saved)); + + a = a_saved; + b = b_saved; + EXPECT(libj2_j2u_add_j2u_to_j2u_overflow(&a, &b, &b) == r_overflow); + EXPECT(libj2_j2u_eq_j2u(&b, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); +} + + +static void +check(uintmax_t a_high, uintmax_t a_low, uintmax_t b_high, uintmax_t b_low) +{ + uintmax_t r_high = 0, r_low = 0, carry = 0; + int r_overflow; + unsigned i; + + for (i = 0; i < LIBJ2_JU_BIT; i++) { + carry += (a_low >> i) & 1U; + carry += (b_low >> i) & 1U; + r_low |= (carry & 1U) << i; + carry >>= 1; + } + + for (i = 0; i < LIBJ2_JU_BIT; i++) { + carry += (a_high >> i) & 1U; + carry += (b_high >> i) & 1U; + r_high |= (carry & 1U) << i; + carry >>= 1; + } + + r_overflow = (int)carry; + check_(a_high, a_low, b_high, b_low, r_high, r_low, r_overflow); +} + + +static void +check_manual(uintmax_t a_high, uintmax_t a_low, uintmax_t b_high, uintmax_t b_low, + uintmax_t r_high, uintmax_t r_low, int r_overflow) +{ + check_(a_high, a_low, b_high, b_low, r_high, r_low, r_overflow); + check(a_high, a_low, b_high, b_low); +} + + +static void +check_double(uintmax_t high, uintmax_t low) +{ + struct libj2_j2u a, r, a_saved, expected, b; + uintmax_t expected_high = (high << 1 | low >> (LIBJ2_JU_BIT - 1U)); + uintmax_t expected_low = low << 1; + int expected_overflow = !!(high >> (LIBJ2_JU_BIT - 1U)); + + a_saved = (struct libj2_j2u){.high = high, .low = low}; + expected = (struct libj2_j2u){.high = expected_high, .low = expected_low}; + + a = a_saved; + b = a_saved; + libj2_j2u_add_j2u(&a, &b); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + + a = a_saved; + libj2_j2u_add_j2u(&a, &a); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + libj2_j2u_add_j2u_to_j2u(&a, &a, &r); + EXPECT(libj2_j2u_eq_j2u(&r, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); + + a = a_saved; + libj2_j2u_add_j2u_to_j2u(&a, &a, &a); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + EXPECT(libj2_j2u_add_j2u_overflow(&a, &a) == expected_overflow); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); + + r = (struct libj2_j2u){111, 222}; + a = a_saved; + EXPECT(libj2_j2u_add_j2u_to_j2u_overflow(&a, &a, &r) == expected_overflow); + EXPECT(libj2_j2u_eq_j2u(&r, &expected)); + EXPECT(libj2_j2u_eq_j2u(&a, &a_saved)); + + a = a_saved; + EXPECT(libj2_j2u_add_j2u_to_j2u_overflow(&a, &a, &a) == expected_overflow); + EXPECT(libj2_j2u_eq_j2u(&a, &expected)); +} + + +int +main(void) +{ + unsigned i; + + srand((unsigned)time(NULL)); + + check_manual(0, 0, 0, 0, 0, 0, 0); + check_manual(0, 1, 0, 1, 0, 2, 0); + check_manual(0, UINTMAX_MAX, 0, 1, 1, 0, 0); + check_manual(0, UINTMAX_MAX, 0, UINTMAX_MAX, 1, UINTMAX_MAX - 1U, 0); + check_manual(UINTMAX_MAX, UINTMAX_MAX, UINTMAX_MAX, UINTMAX_MAX, UINTMAX_MAX, UINTMAX_MAX - 1U, 1); + + for (i = 0; i < 256; i++) + check(random_ju(), random_ju(), random_ju(), random_ju()); + + check_double(0, 0); + check_double(0, UINTMAX_MAX); + check_double(UINTMAX_MAX, 0); + check_double(UINTMAX_MAX, UINTMAX_MAX); + for (i = 0; i < 256; i++) { + check_double(0, random_ju()); + check_double(random_ju(), 0); + check_double(random_ju(), UINTMAX_MAX); + check_double(random_ju(), random_ju()); + check_double(UINTMAX_MAX, random_ju()); + } + + return 0; +} + +#endif |