1 files changed, 149 insertions, 0 deletions
diff --git a/libj2_ju_mul_ju_to_j2u.c b/libj2_ju_mul_ju_to_j2u.c
new file mode 100644
index 0000000..11daad4
--- /dev/null
+++ b/libj2_ju_mul_ju_to_j2u.c
@@ -0,0 +1,149 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_ju_mul_ju_to_j2u(uintmax_t a, uintmax_t b, struct libj2_j2u *res);
+/* 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
+mul(uintmax_t a, uintmax_t b, struct libj2_j2u *expected)
+{
+	struct libj2_j2u c;
+	unsigned i;
+
+	libj2_j2u_zero(expected);
+	for (i = 0; i < LIBJ2_JU_BIT; i++, b >>= 1) {
+		if (b & 1U) {
+			libj2_ju_lsh_to_j2u(a, i, &c);
+			libj2_j2u_add_j2u(expected, &c);
+		}
+	}
+}
+
+
+int
+main(void)
+{
+	struct libj2_j2u r, expected;
+	uintmax_t u, v;
+	unsigned i;
+
+	srand((unsigned)time(NULL));
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(0, 0, &r);
+	EXPECT(libj2_j2u_is_zero(&r));
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(0, 1, &r);
+	EXPECT(libj2_j2u_is_zero(&r));
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(0, UINTMAX_MAX, &r);
+	EXPECT(libj2_j2u_is_zero(&r));
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(1, 0, &r);
+	EXPECT(libj2_j2u_is_zero(&r));
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(UINTMAX_MAX, 0, &r);
+	EXPECT(libj2_j2u_is_zero(&r));
+
+	for (i = 0; i < 32; i++) {
+		r = (struct libj2_j2u){111, 222};
+		libj2_ju_mul_ju_to_j2u(0, random_ju(), &r);
+		EXPECT(libj2_j2u_is_zero(&r));
+
+		r = (struct libj2_j2u){111, 222};
+		libj2_ju_mul_ju_to_j2u(random_ju(), 0, &r);
+		EXPECT(libj2_j2u_is_zero(&r));
+	}
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(1, 1, &r);
+	EXPECT(r.high == 0);
+	EXPECT(r.low == 1);
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(4, 4, &r);
+	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_mul_ju_to_j2u(1, v, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == v);
+
+		r = (struct libj2_j2u){111, 222};
+		v = random_ju();
+		libj2_ju_mul_ju_to_j2u(v, 1, &r);
+		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};
+		libj2_ju_mul_ju_to_j2u(u, v, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == u * v);
+
+		libj2_ju_mul_ju_to_j2u(v, u, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == u * v);
+	}
+
+	r = (struct libj2_j2u){111, 222};
+	libj2_ju_mul_ju_to_j2u(UINTMAX_MAX, UINTMAX_MAX, &r);
+	EXPECT(r.high == UINTMAX_MAX - 1U);
+	EXPECT(r.low == 1);
+
+	for (i = 0; i < 256; i++) {
+		u = random_ju();
+		v = random_ju();
+
+		mul(u, v, &expected);
+
+		r = (struct libj2_j2u){111, 222};
+		libj2_ju_mul_ju_to_j2u(u, v, &r);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+
+		libj2_ju_mul_ju_to_j2u(v, u, &r);
+		EXPECT(libj2_j2u_eq_j2u(&r, &expected));
+	}
+
+	return 0;
+}
+
+#endif