Add signed arithmetics

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 221 insertions, 0 deletions

diff --git a/libj2_ji_mul_ji_to_j2i.c b/libj2_ji_mul_ji_to_j2i.c
new file mode 100644
index 0000000..ada66cc
--- /dev/null
+++ b/libj2_ji_mul_ji_to_j2i.c
@@ -0,0 +1,221 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_ji_mul_ji_to_j2i(intmax_t a, intmax_t b, struct libj2_j2i *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 intmax_t
+random_ji(void)
+{
+	uintmax_t u;
+	u = random_small_ju(LIBJ2_JU_BIT);
+	if (u >> (LIBJ2_JU_BIT - 1U))
+		return (intmax_t)u;
+	return (intmax_t)~u - 1;
+}
+
+
+static void
+mul(intmax_t a, intmax_t b, struct libj2_j2i *expected)
+{
+	int neg = (a < 0) ^ (b < 0);
+	uintmax_t u = a < 0 ? (uintmax_t)-(a + 1U) + 1U : (uintmax_t)a;
+	uintmax_t v = b < 0 ? (uintmax_t)-(b + 1U) + 1U : (uintmax_t)b;
+	struct libj2_j2u c;
+	libj2_ju_mul_ju_to_j2u(u, v, &c);
+	libj2_j2u_to_j2i(&c, expected);
+	if (neg)
+		libj2_minus_j2i(expected);
+}
+
+
+int
+main(void)
+{
+	struct libj2_j2i r, expected;
+	intmax_t u, v;
+	unsigned i;
+
+	srand((unsigned)time(NULL));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, 1, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, -1, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, INTMAX_MAX, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, -INTMAX_MAX, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(0, INTMAX_MIN, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(1, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-1, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(INTMAX_MAX, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-INTMAX_MAX, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(INTMAX_MIN, 0, &r);
+	EXPECT(libj2_j2i_is_zero(&r));
+
+	for (i = 0; i < 32; i++) {
+		r = (struct libj2_j2i){111, 222};
+		libj2_ji_mul_ji_to_j2i(0, random_ji(), &r);
+		EXPECT(libj2_j2i_is_zero(&r));
+
+		r = (struct libj2_j2i){111, 222};
+		libj2_ji_mul_ji_to_j2i(random_ji(), 0, &r);
+		EXPECT(libj2_j2i_is_zero(&r));
+	}
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(1, 1, &r);
+	EXPECT(r.high == 0);
+	EXPECT(r.low == 1);
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(4, 4, &r);
+	EXPECT(r.high == 0);
+	EXPECT(r.low == 16);
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(2, 3, &r);
+	EXPECT(libj2_j2i_eq_ji(&r, 6));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(2, -3, &r);
+	EXPECT(libj2_j2i_eq_ji(&r, -6));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-2, 3, &r);
+	EXPECT(libj2_j2i_eq_ji(&r, -6));
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-2, -3, &r);
+	EXPECT(libj2_j2i_eq_ji(&r, 6));
+
+	for (i = 0; i < 32; i++) {
+		r = (struct libj2_j2i){111, 222};
+		v = (intmax_t)(random_ju() >> 1);
+		libj2_ji_mul_ji_to_j2i(1, v, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == (uintmax_t)v);
+
+		r = (struct libj2_j2i){111, 222};
+		v = (intmax_t)(random_ju() >> 1);
+		libj2_ji_mul_ji_to_j2i(v, 1, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == (uintmax_t)v);
+	}
+
+	for (i = 0; i < 32; i++) {
+		u = (intmax_t)random_hju();
+		v = (intmax_t)random_hju();
+
+		r = (struct libj2_j2i){111, 222};
+		libj2_ji_mul_ji_to_j2i(u, v, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == (uintmax_t)u * (uintmax_t)v);
+
+		libj2_ji_mul_ji_to_j2i(v, u, &r);
+		EXPECT(r.high == 0);
+		EXPECT(r.low == (uintmax_t)u * (uintmax_t)v);
+	}
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(INTMAX_MAX, INTMAX_MAX, &r);
+	EXPECT(r.high == (uintmax_t)INTMAX_MAX >> 1);
+	EXPECT(r.low == 1);
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(INTMAX_MAX, -INTMAX_MAX, &r);
+	libj2_minus_j2i(&r);
+	EXPECT(r.high == (uintmax_t)INTMAX_MAX >> 1);
+	EXPECT(r.low == 1);
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-INTMAX_MAX, INTMAX_MAX, &r);
+	libj2_minus_j2i(&r);
+	EXPECT(r.high == (uintmax_t)INTMAX_MAX >> 1);
+	EXPECT(r.low == 1);
+
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(-INTMAX_MAX, -INTMAX_MAX, &r);
+	EXPECT(r.high == (uintmax_t)INTMAX_MAX >> 1);
+	EXPECT(r.low == 1);
+
+#if INTMAX_MIN + 1 == -INTMAX_MAX
+	r = (struct libj2_j2i){111, 222};
+	libj2_ji_mul_ji_to_j2i(INTMAX_MIN, INTMAX_MIN, &r);
+	EXPECT(r.high == ((uintmax_t)INTMAX_MAX + 1U) >> 1);
+	EXPECT(r.low == 0);
+#endif
+
+	for (i = 0; i < 256; i++) {
+		u = random_ji();
+		v = random_ji();
+
+		mul(u, v, &expected);
+
+		r = (struct libj2_j2i){111, 222};
+		libj2_ji_mul_ji_to_j2i(u, v, &r);
+		EXPECT(libj2_j2i_eq_j2i(&r, &expected));
+
+		libj2_ji_mul_ji_to_j2i(v, u, &r);
+		EXPECT(libj2_j2i_eq_j2i(&r, &expected));
+	}
+
+	return 0;
+}
+
+#endif