1 files changed, 94 insertions, 0 deletions
diff --git a/libj2_ji_sub_ji_to_j2i.c b/libj2_ji_sub_ji_to_j2i.c
new file mode 100644
index 0000000..018c93c
--- /dev/null
+++ b/libj2_ji_sub_ji_to_j2i.c
@@ -0,0 +1,94 @@
+/* See LICENSE file for copyright and license details. */
+#include "common.h"
+#ifndef TEST
+
+extern inline void libj2_ji_sub_ji_to_j2i(intmax_t a, intmax_t b, struct libj2_j2i *res);
+/* 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 ua, uintmax_t ub)
+{
+	intmax_t a = ua >> (LIBJ2_JU_BIT - 1U) ? -(intmax_t)~ua - 1 : (intmax_t)ua;
+	intmax_t b = ub >> (LIBJ2_JU_BIT - 1U) ? -(intmax_t)~ub - 1 : (intmax_t)ub;
+	struct libj2_j2i r, expected;
+	struct libj2_j2u wa, wb;
+
+#if INTMAX_MIN + 1 != -INTMAX_MAX
+	if (ua == (UINTMAX >> 1) + 1U || ub == (UINTMAX >> 1) + 1U)
+		return;
+#endif
+
+	wa.low = ua;
+	wb.low = ub;
+
+	wa.high = a < 0 ? UINTMAX_MAX : 0;
+	wb.high = b < 0 ? UINTMAX_MAX : 0;
+
+	libj2_minus_j2u(&wb);
+	libj2_j2u_add_j2u_to_j2u(&wa, &wb, (void *)&expected);
+	libj2_ji_sub_ji_to_j2i(a, b, &r);
+	EXPECT(libj2_j2i_eq_j2i(&r, &expected));
+}
+
+
+int
+main(void)
+{
+	uintmax_t a, b, max, min, umax, vs[12];
+	unsigned i, j, k;
+
+	srand((unsigned)time(NULL));
+
+	umax = UINTMAX_MAX;
+	max = umax >> 1;
+	min = ~max;
+
+	vs[0] = 0U;
+	vs[1] = 1U;
+	vs[2] = 2U;
+	vs[3] = umax - 0U;
+	vs[4] = umax - 1U;
+	vs[5] = umax - 2U;
+	vs[6] = max - 0U;
+	vs[7] = max - 1U;
+	vs[8] = max - 2U;
+	vs[9] = min + 0U;
+	vs[10] = min + 1U;
+	vs[11] = min + 2U;
+
+	for (i = 0; i < 12U; i++)
+		for (j = 0; j < 12U; j++)
+			check(vs[i], vs[j]);
+	for (j = 0; j < 256U; j++) {
+		for (k = 0; k < 4U; k++) {
+			a = random_ju() >> 1;
+			b = random_ju() >> 1;
+			if (k & 1U) a = ~a;
+			if (k & 2U) b = ~b;
+			check(a, b);
+			for (i = 0; k < 2U && i < 12U; i++) {
+				check(a, vs[i]);
+				check(vs[i], a);
+			}
+		}
+	}
+
+	return 0;
+}
+
+#endif