/*      $NetBSD: t_long_double.c,v 1.8 2026/04/10 20:54:59 rillig Exp $ */

/*-
 * Copyright (c) 2026 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Roland Illig.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
#include <sys/cdefs.h>
__RCSID("$NetBSD: t_long_double.c,v 1.8 2026/04/10 20:54:59 rillig Exp $");

#include <atf-c.h>

#include <float.h>
#include <inttypes.h>
#include <limits.h>
#include <stdint.h>

static void
test_ldbl_cmp(void)
{
        static const long double ns[] = {
                -0x1.0p63L,
                -0x1.0p62L,
                -0x1.0p60L,
                -0x1.0p10L,
                -0x1.0p1L,
                -0x1.0p0L,
                0.0L,
                +0x1.0p0L,
                +0x1.0p1L,
                +0x1.0p10L,
                +0x1.0p60L,
                +0x1.0p62L,
                +0x1.0p63L,
        };

        for (size_t i = 0; i < __arraycount(ns); i++) {
                for (size_t j = 0; j < __arraycount(ns); j++) {
                        if (i < j)
                                ATF_CHECK_MSG(ns[i] < ns[j],
                                    "%s: want %Lf (%La) < %Lf (%La)",
                                    __func__, ns[i], ns[i], ns[j], ns[j]);
                        if (i <= j)
                                ATF_CHECK_MSG(ns[i] <= ns[j],
                                    "%s: want %Lf (%La) <= %Lf (%La)",
                                   __func__,  ns[i], ns[i], ns[j], ns[j]);
                        if (i == j)
                                ATF_CHECK_MSG(ns[i] == ns[j],
                                    "%s: want %Lf (%La) == %Lf (%La)",
                                    __func__, ns[i], ns[i], ns[j], ns[j]);
                        if (i != j)
                                ATF_CHECK_MSG(ns[i] != ns[j],
                                    "%s: want %Lf (%La) != %Lf (%La)",
                                    __func__, ns[i], ns[i], ns[j], ns[j]);
                        if (i >= j)
                                ATF_CHECK_MSG(ns[i] >= ns[j],
                                    "%s: want %Lf (%La) >= %Lf (%La)",
                                    __func__, ns[i], ns[i], ns[j], ns[j]);
                        if (i > j)
                                ATF_CHECK_MSG(ns[i] > ns[j],
                                    "%s: want %Lf (%La) > %Lf (%La)",
                                    __func__, ns[i], ns[i], ns[j], ns[j]);
                }
        }
}

static void
test_int64_to_ldbl(void)
{
        static const struct testcase {
                int64_t arg;
                long double want;
        } testcases[] = {
                { INT64_MIN, -0x1.0p63L },
                { -(1LL << 62), -0x1.0p62L },
                { -(1LL << 60), -0x1.0p60L },
                { -(1LL << 40), -0x1.0p40L },
                { -(1LL << 20), -0x1.0p20L },
                { -(1LL << 10), -0x1.0p10L },
                { -1, -1.0L },
                { 0, +0.0L },
                { +1, +1.0L },
                { +(1LL << 10), +0x1.0p10L },
                { +(1LL << 20), +0x1.0p20L },
                { +(1LL << 40), +0x1.0p40L },
                { +(1LL << 60), +0x1.0p60L },
                { +(1LL << 62), +0x1.0p62L },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                long double have = (long double)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %Lf (%La) for %" PRId64 " (0x%016" PRIx64 "), "
                    "have %Lf (%La)",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

static void
test_ldbl_to_int64(void)
{
        static const struct testcase {
                long double arg;
                int64_t want;
        } testcases[] = {
                { -0x1.0p63L, INT64_MIN },
                { -1.0L, -1 },
                { -0.0L, 0 },
                { +0.0L, 0 },
                { +1.0L, 1 },
                { +0x1.0p62L, +1LL << 62 },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                int64_t have = (int64_t)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %" PRId64 " (0x%016" PRIx64 ") for %Lf (%La), "
                    "have %" PRId64 " (0x%016" PRIx64 ")",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

static void
test_uint64_to_ldbl(void)
{
        static const struct testcase {
                uint64_t arg;
                long double want;
        } testcases[] = {
                { 0, +0.0L },
                { +1, +1.0L },
                { +1ULL << 63, +0x1.0p63L },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                long double have = (long double)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %Lf (%La) for %" PRIu64 " (0x%016" PRIx64 "), "
                    "have %Lf (%La)",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

static void
test_ldbl_to_uint64(void)
{
        static const struct testcase {
                long double arg;
                uint64_t want;
        } testcases[] = {
// C23 6.3.1.4p1 says the portable range goes from -1 + epsilon to
// (1<<64) - epsilon. Try some values outside the portable range, to show the
// differences between platforms.
#if 1
#if __aarch64__ || __m68k__ || __riscv__
                // Negative values saturate to 0.
                { -0xf.0p60L,   0 },
                { -0x8.0p60L,   0 },
                { -0x4.0p60L,   0 },
                { -1.0L,        0 },
#elif __mips__
                // Negative values produce strange results.
                { -0xf.0p60L,   0x1000000000000000 },
                { -0x8.0p60L,   0x8000000000000000 },
                { -0x4.0p60L,   0xc000000000000000 },
                { -1.0L,        0x00000000ffffffff },
#elif __sparc64__
                // Negative values are taken modulo 2^64.
                { -0xf.0p60L,   0x1000000000000000 },
                { -0x8.0p60L,   0x8000000000000000 },
                { -0x4.0p60L,   0xc000000000000000 },
                { -1.0L,        0xffffffffffffffff },
#elif __powerpc__ || __sparc__
                // Negative values produce strange results.
                { -0xf.0p60L,   0x8000000080000000 },
                { -0x8.0p60L,   0x8000000080000000 },
                { -0x4.0p60L,   0xc000000080000000 },
                { -1.0L,        0x00000000ffffffff },
#elif __x86_64__ || __i386__
                // Negative values below INT64_MIN saturate.
                { -0xf.0p60L,   0x8000000000000000 },
                { -0x8.0p60L,   0x8000000000000000 },
                { -0x4.0p60L,   0xc000000000000000 },
                { -1.0L,        0xffffffffffffffff },
#else
// Other platforms may fall into one of the above categories,
// or they may differ even further.
#endif
#endif
                { -0.5L,        0 },
                { -0.0L,        0 },
                { +0.0L,        0 },
                { +0.875L,      0 },
                { +1.0L,        1 },
                { +0x1.0p63L,   0x8000000000000000 },
                { +0xf.0p60L,   0xf000000000000000 },
                { +0xf.fffp60L, 0xffff000000000000 },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                uint64_t have = (uint64_t)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %" PRIu64 " (0x%016" PRIx64 ") for %Lf (%La), "
                    "have %" PRIu64 " (0x%016" PRIx64 ")",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

static void
test_dbl_to_ldbl(void)
{
        static const struct testcase {
                double arg;
                long double want;
        } testcases[] = {
                { -DBL_MAX, -DBL_MAX },
                { -1.0, -1.0L },
                { -DBL_MIN, -DBL_MIN },
                { -0.0, -0.0L },
                { +0.0, +0.0L },
                { +DBL_MIN, +DBL_MIN },
                { +1.0, +1.0L },
                { +DBL_MAX, +DBL_MAX },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                long double have = (long double)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %Lf (%La) for %f (%a), have %Lf (%La)",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

static void
test_ldbl_to_dbl(void)
{
        static const struct testcase {
                long double arg;
                double want;
        } testcases[] = {
                { -DBL_MAX, -DBL_MAX },
                { -1.0L, -1.0 },
                { -DBL_MIN, -DBL_MIN },
                { -0.0L, -0.0 },
                { +0.0L, +0.0 },
                { +DBL_MIN, +DBL_MIN },
                { +1.0L, +1.0 },
                { +DBL_MAX, +DBL_MAX },
        };

        for (size_t i = 0; i < __arraycount(testcases); i++) {
                const struct testcase *c = testcases + i;
                double have = (double)c->arg;
                ATF_CHECK_MSG(have == c->want,
                    "%s: want %f (%a) for %Lf (%La), have %f (%a)",
                    __func__, c->want, c->want, c->arg, c->arg, have, have);
        }
}

ATF_TC(long_double);

ATF_TC_HEAD(long_double, tc)
{

        atf_tc_set_md_var(tc, "descr", "Test 'long double' operations");
}

ATF_TC_BODY(long_double, tc)
{
        test_ldbl_cmp();
        test_int64_to_ldbl();
        test_ldbl_to_int64();
        test_uint64_to_ldbl();
        test_ldbl_to_uint64();
        test_dbl_to_ldbl();
        test_ldbl_to_dbl();
}

ATF_TP_ADD_TCS(tp)
{

        ATF_TP_ADD_TC(tp, long_double);

        return atf_no_error();
}