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serfloat: improve/simplify tests
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@sipa
sipa committed Feb 20, 2024
1 parent b45f1f5 commit 6e873df
Showing 1 changed file with 69 additions and 44 deletions.
113 changes: 69 additions & 44 deletions src/test/serfloat_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -37,6 +37,7 @@ uint64_t TestDouble(double f) {
} // namespace

BOOST_AUTO_TEST_CASE(double_serfloat_tests) {
// Test specific values against their expected encoding.
BOOST_CHECK_EQUAL(TestDouble(0.0), 0U);
BOOST_CHECK_EQUAL(TestDouble(-0.0), 0x8000000000000000);
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::infinity()), 0x7ff0000000000000U);
Expand All @@ -46,52 +47,76 @@ BOOST_AUTO_TEST_CASE(double_serfloat_tests) {
BOOST_CHECK_EQUAL(TestDouble(2.0), 0x4000000000000000ULL);
BOOST_CHECK_EQUAL(TestDouble(4.0), 0x4010000000000000ULL);
BOOST_CHECK_EQUAL(TestDouble(785.066650390625), 0x4088888880000000ULL);
BOOST_CHECK_EQUAL(TestDouble(3.7243058682384174), 0x400dcb60e0031440);
BOOST_CHECK_EQUAL(TestDouble(91.64070592566159), 0x4056e901536d447a);
BOOST_CHECK_EQUAL(TestDouble(-98.63087668642575), 0xc058a860489c007a);
BOOST_CHECK_EQUAL(TestDouble(4.908737756962054), 0x4013a28c268b2b70);
BOOST_CHECK_EQUAL(TestDouble(77.9247330021754), 0x40537b2ed3547804);
BOOST_CHECK_EQUAL(TestDouble(40.24732825357566), 0x40441fa873c43dfc);
BOOST_CHECK_EQUAL(TestDouble(71.39395607929222), 0x4051d936938f27b6);
BOOST_CHECK_EQUAL(TestDouble(58.80100710817612), 0x404d668766a2bd70);
BOOST_CHECK_EQUAL(TestDouble(-30.10665786964975), 0xc03e1b4dee1e01b8);
BOOST_CHECK_EQUAL(TestDouble(60.15231509068704), 0x404e137f0f969814);
BOOST_CHECK_EQUAL(TestDouble(-48.15848711335961), 0xc04814494e445bc6);
BOOST_CHECK_EQUAL(TestDouble(26.68450101125353), 0x403aaf3b755169b0);
BOOST_CHECK_EQUAL(TestDouble(-65.72071986604303), 0xc0506e2046378ede);
BOOST_CHECK_EQUAL(TestDouble(17.95575825512381), 0x4031f4ac92b0a388);
BOOST_CHECK_EQUAL(TestDouble(-35.27171863226279), 0xc041a2c7ad17a42a);
BOOST_CHECK_EQUAL(TestDouble(-8.58810329425124), 0xc0212d1bdffef538);
BOOST_CHECK_EQUAL(TestDouble(88.51393044338977), 0x405620e43c83b1c8);
BOOST_CHECK_EQUAL(TestDouble(48.07224932612732), 0x4048093f77466ffc);
BOOST_CHECK_EQUAL(TestDouble(9.867348871395659e+117), 0x586f4daeb2459b9f);
BOOST_CHECK_EQUAL(TestDouble(-1.5166424385129721e+206), 0xeabe3bbc484bd458);
BOOST_CHECK_EQUAL(TestDouble(-8.585156555624594e-275), 0x8707c76eee012429);
BOOST_CHECK_EQUAL(TestDouble(2.2794371091628822e+113), 0x5777b2184458f4ee);
BOOST_CHECK_EQUAL(TestDouble(-1.1290476594131867e+163), 0xe1c91893d3488bb0);
BOOST_CHECK_EQUAL(TestDouble(9.143848423979275e-246), 0x0d0ff76e5f2620a3);
BOOST_CHECK_EQUAL(TestDouble(-2.8366718125941117e+81), 0xd0d7ec7e754b394a);
BOOST_CHECK_EQUAL(TestDouble(-1.2754409481684012e+229), 0xef80d32f8ec55342);
BOOST_CHECK_EQUAL(TestDouble(6.000577060053642e-186), 0x197a1be7c8209b6a);
BOOST_CHECK_EQUAL(TestDouble(2.0839423284378986e-302), 0x014c94f8689cb0a5);
BOOST_CHECK_EQUAL(TestDouble(-1.422140051483753e+259), 0xf5bd99271d04bb35);
BOOST_CHECK_EQUAL(TestDouble(-1.0593973991188853e+46), 0xc97db0cdb72d1046);
BOOST_CHECK_EQUAL(TestDouble(2.62945125875249e+190), 0x67779b36366c993b);
BOOST_CHECK_EQUAL(TestDouble(-2.920377657275094e+115), 0xd7e7b7b45908e23b);
BOOST_CHECK_EQUAL(TestDouble(9.790289014855851e-118), 0x27a3c031cc428bcc);
BOOST_CHECK_EQUAL(TestDouble(-4.629317182034961e-114), 0xa866ccf0b753705a);
BOOST_CHECK_EQUAL(TestDouble(-1.7674605603846528e+279), 0xf9e8ed383ffc3e25);
BOOST_CHECK_EQUAL(TestDouble(2.5308171727712605e+120), 0x58ef5cd55f0ec997);
BOOST_CHECK_EQUAL(TestDouble(-1.05034156412799e+54), 0xcb25eea1b9350fa0);

if (std::numeric_limits<double>::is_iec559) {
BOOST_CHECK_EQUAL(sizeof(double), 8U);
BOOST_CHECK_EQUAL(sizeof(uint64_t), 8U);
// Test extreme values
TestDouble(std::numeric_limits<double>::min());
TestDouble(-std::numeric_limits<double>::min());
TestDouble(std::numeric_limits<double>::max());
TestDouble(-std::numeric_limits<double>::max());
TestDouble(std::numeric_limits<double>::lowest());
TestDouble(-std::numeric_limits<double>::lowest());
TestDouble(std::numeric_limits<double>::quiet_NaN());
TestDouble(-std::numeric_limits<double>::quiet_NaN());
TestDouble(std::numeric_limits<double>::signaling_NaN());
TestDouble(-std::numeric_limits<double>::signaling_NaN());
TestDouble(std::numeric_limits<double>::denorm_min());
TestDouble(-std::numeric_limits<double>::denorm_min());
// On IEC559-compatible systems, construct doubles to test from the encoding.
for (int j = 0; j < 1000; ++j) {
// Iterate over 9 specific bits exhaustively; the others are chosen randomly.
// These specific bits are the sign bit, and the 2 top and bottom bits of
// exponent and mantissa in the IEEE754 binary64 format.
for (int x = 0; x < 512; ++x) {
uint64_t v = InsecureRandBits(64);
v &= ~(uint64_t{1} << 0);
if (x & 1) v |= (uint64_t{1} << 0);
v &= ~(uint64_t{1} << 1);
if (x & 2) v |= (uint64_t{1} << 1);
v &= ~(uint64_t{1} << 50);
if (x & 4) v |= (uint64_t{1} << 50);
v &= ~(uint64_t{1} << 51);
if (x & 8) v |= (uint64_t{1} << 51);
v &= ~(uint64_t{1} << 52);
if (x & 16) v |= (uint64_t{1} << 52);
v &= ~(uint64_t{1} << 53);
if (x & 32) v |= (uint64_t{1} << 53);
v &= ~(uint64_t{1} << 61);
if (x & 64) v |= (uint64_t{1} << 61);
v &= ~(uint64_t{1} << 62);
if (x & 128) v |= (uint64_t{1} << 62);
v &= ~(uint64_t{1} << 63);
if (x & 256) v |= (uint64_t{1} << 63);
double f;
memcpy(&f, &v, 8);
TestDouble(f);
// Test extreme values
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::min()), 0x10000000000000);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::min()), 0x8010000000000000);
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::max()), 0x7fefffffffffffff);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::max()), 0xffefffffffffffff);
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::lowest()), 0xffefffffffffffff);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::lowest()), 0x7fefffffffffffff);
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::denorm_min()), 0x1);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::denorm_min()), 0x8000000000000001);
// Note that all NaNs are encoded the same way.
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::quiet_NaN()), 0x7ff8000000000000);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::quiet_NaN()), 0x7ff8000000000000);
BOOST_CHECK_EQUAL(TestDouble(std::numeric_limits<double>::signaling_NaN()), 0x7ff8000000000000);
BOOST_CHECK_EQUAL(TestDouble(-std::numeric_limits<double>::signaling_NaN()), 0x7ff8000000000000);

// Construct doubles to test from the encoding.
static_assert(sizeof(double) == 8);
static_assert(sizeof(uint64_t) == 8);
for (int j = 0; j < 1000; ++j) {
// Iterate over 9 specific bits exhaustively; the others are chosen randomly.
// These specific bits are the sign bit, and the 2 top and bottom bits of
// exponent and mantissa in the IEEE754 binary64 format.
for (int x = 0; x < 512; ++x) {
uint64_t v = InsecureRandBits(64);
int x_pos = 0;
for (int v_pos : {0, 1, 50, 51, 52, 53, 61, 62, 63}) {
v &= ~(uint64_t{1} << v_pos);
if ((x >> (x_pos++)) & 1) v |= (uint64_t{1} << v_pos);
}
double f;
memcpy(&f, &v, 8);
TestDouble(f);
}
}
}
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