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-rw-r--r--libj2_j2u_mul_j2u_destructive.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/libj2_j2u_mul_j2u_destructive.c b/libj2_j2u_mul_j2u_destructive.c
new file mode 100644
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--- /dev/null
+++ b/libj2_j2u_mul_j2u_destructive.c
@@ -0,0 +1,267 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_j2u_mul_j2u_destructive(struct libj2_j2u *restrict a /*result */, struct libj2_j2u *restrict b /*destructed */);
+/* 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 void
+random_j2u(struct libj2_j2u *a)
+{
+ a->high = random_ju();
+ a->low = random_ju();
+}
+
+
+static int
+refmul(const struct libj2_j2u *a, const struct libj2_j2u *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++) {
+ if (libj2_j2u_test_bit(b, i)) {
+ 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, const struct libj2_j2u *b, struct libj2_j2u *expected, int expect_overflow)
+{
+ struct libj2_j2u t, x, a_saved = *a, b_saved = *b;
+
+ *expected = *a;
+ libj2_j2u_mul_j2u(expected, b);
+
+ t = (struct libj2_j2u){111, 222};
+ libj2_j2u_mul_j2u_to_j2u(a, b, &t);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+ EXPECT(libj2_j2u_eq_j2u(a, &a_saved));
+ EXPECT(libj2_j2u_eq_j2u(b, &b_saved));
+
+ t = *a;
+ EXPECT(libj2_j2u_mul_j2u_overflow(&t, b) == expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+ EXPECT(libj2_j2u_eq_j2u(b, &b_saved));
+
+ t = (struct libj2_j2u){111, 222};
+ EXPECT(libj2_j2u_mul_j2u_to_j2u_overflow(a, b, &t) == expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+ EXPECT(libj2_j2u_eq_j2u(a, &a_saved));
+ EXPECT(libj2_j2u_eq_j2u(b, &b_saved));
+
+ t = *a;
+ x = *b;
+ libj2_j2u_mul_j2u_destructive(&t, &x);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+
+ t = *a;
+ x = *b;
+ EXPECT(libj2_j2u_mul_j2u_overflow_destructive(&t, &x) == expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+
+ if (a == b) {
+ t = *a;
+ libj2_j2u_mul_j2u(&t, &t);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+
+ t = *a;
+ libj2_j2u_mul_j2u_to_j2u(&t, &t, &t);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+
+ t = *a;
+ EXPECT(libj2_j2u_mul_j2u_overflow(&t, &t) == expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+
+ t = *a;
+ EXPECT(libj2_j2u_mul_j2u_to_j2u_overflow(&t, &t, &t) == expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&t, expected));
+ }}
+
+
+static void
+mul(const struct libj2_j2u *a, const struct libj2_j2u *b, struct libj2_j2u *expected, int expect_overflow)
+{
+ struct libj2_j2u t;
+
+ if (a == b) {
+ t = *a;
+ mul_(a, &t, expected, expect_overflow);
+ mul_(a, a, expected, expect_overflow);
+ } else {
+ mul_(a, b, expected, expect_overflow);
+ mul_(b, a, expected, expect_overflow);
+ }
+}
+
+
+int
+main(void)
+{
+ const struct libj2_j2u zero = {0, 0};
+ const struct libj2_j2u one = {.high = 0, .low = 1};
+ const struct libj2_j2u four = {.high = 0, .low = 4};
+ const struct libj2_j2u ju_max = {.high = 0, .low = UINTMAX_MAX};
+ const struct libj2_j2u j2u_max = {.high = UINTMAX_MAX, .low = UINTMAX_MAX};
+ struct libj2_j2u a, b, r, expected;
+ uintmax_t u, v;
+ unsigned i;
+ int expect_overflow;
+
+ srand((unsigned)time(NULL));
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&zero, &zero, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&zero, &one, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&zero, &ju_max, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&one, &zero, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&ju_max, &zero, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ for (i = 0; i < 32; i++) {
+ r = (struct libj2_j2u){111, 222};
+ v = random_ju();
+ libj2_ju_to_j2u(v, &a);
+ mul(&zero, &a, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ v = random_ju();
+ libj2_ju_to_j2u(v, &a);
+ mul(&a, &zero, &r, 0);
+
+ EXPECT(libj2_j2u_is_zero(&r));
+ r = (struct libj2_j2u){111, 222};
+ random_j2u(&a);
+ mul(&zero, &a, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+
+ r = (struct libj2_j2u){111, 222};
+ random_j2u(&a);
+ mul(&a, &zero, &r, 0);
+ EXPECT(libj2_j2u_is_zero(&r));
+ }
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&one, &one, &r, 0);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == 1);
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&four, &four, &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();
+ libj2_ju_to_j2u(v, &a);
+ mul(&one, &a, &r, 0);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == v);
+
+ r = (struct libj2_j2u){111, 222};
+ v = random_ju();
+ libj2_ju_to_j2u(v, &a);
+ mul(&a, &one, &r, 0);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == v);
+ }
+
+ for (i = 0; i < 32; i++) {
+ u = random_hju();
+ v = random_hju();
+
+ libj2_ju_to_j2u(u, &a);
+ libj2_ju_to_j2u(v, &b);
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&a, &b, &r, 0);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == u * v);
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&b, &a, &r, 0);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == u * v);
+ }
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&ju_max, &ju_max, &r, 0);
+ EXPECT(r.high == UINTMAX_MAX - 1U);
+ EXPECT(r.low == 1);
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&j2u_max, &ju_max, &r, 1);
+ EXPECT(r.high == UINTMAX_MAX);
+ EXPECT(r.low == 1);
+
+ /* self-check */
+ r = (struct libj2_j2u){111, 222};
+ EXPECT(refmul(&j2u_max, &ju_max, &r) == 1);
+ EXPECT(r.high == UINTMAX_MAX);
+ EXPECT(r.low == 1);
+ r = (struct libj2_j2u){111, 222};
+ EXPECT(refmul(&j2u_max, &j2u_max, &r) == 1);
+ EXPECT(r.high == 0);
+ EXPECT(r.low == 1);
+
+ for (i = 0; i < 256; i++) {
+ random_j2u(&a);
+ random_j2u(&b);
+
+ expect_overflow = refmul(&a, &b, &expected);
+
+ r = (struct libj2_j2u){111, 222};
+ mul(&a, &b, &r, expect_overflow);
+ EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+ }
+
+ return 0;
+}
+
+#endif
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