forked from rpms/glibc
66024333e7
Resolves: RHEL-46739
446 lines
14 KiB
Diff
446 lines
14 KiB
Diff
commit 457622c2fa8f9f7435822d5287a437bc8be8090d
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Author: Joseph Myers <josmyers@redhat.com>
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Date: Tue Aug 27 12:41:02 2024 +0000
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Fix strtod subnormal rounding (bug 30220)
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As reported in bug 30220, the implementation of strtod-family
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functions has a bug in the following case: the input string would,
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with infinite exponent range, take one more bit to represent than is
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available in the normal precision of the return type; the value
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represented is in the subnormal range; and there are no nonzero bits
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in the value, below those that can be represented in subnormal
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precision, other than the least significant bit and possibly the
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0.5ulp bit. In this case, round_and_return ends up discarding the
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least significant bit.
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Fix by saving that bit to merge into more_bits (it can't be merged in
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at the time it's computed, because more_bits mustn't include this bit
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in the case of after-rounding tininess detection checking if the
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result is still subnormal when rounded to normal precision, so merging
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this bit into more_bits needs to take place after that check).
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Tested for x86_64.
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diff --git a/stdlib/strtod_l.c b/stdlib/strtod_l.c
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index 5a54d99ae8663641..49b88e9a86be8441 100644
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--- a/stdlib/strtod_l.c
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+++ b/stdlib/strtod_l.c
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@@ -223,6 +223,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
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mp_size_t shift = MIN_EXP - 1 - exponent;
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bool is_tiny = true;
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+ bool old_half_bit = (round_limb & (((mp_limb_t) 1) << round_bit)) != 0;
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more_bits |= (round_limb & ((((mp_limb_t) 1) << round_bit) - 1)) != 0;
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if (shift == MANT_DIG)
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@@ -293,6 +294,7 @@ round_and_return (mp_limb_t *retval, intmax_t exponent, int negative,
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round_bit = shift - 1;
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(void) __mpn_rshift (retval, retval, RETURN_LIMB_SIZE, shift);
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}
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+ more_bits |= old_half_bit;
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/* This is a hook for the m68k long double format, where the
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exponent bias is the same for normalized and denormalized
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numbers. */
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diff --git a/stdlib/tst-strtod-round-data b/stdlib/tst-strtod-round-data
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index 84ab705709b24b6c..9489fbcc9ce7eee2 100644
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--- a/stdlib/tst-strtod-round-data
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+++ b/stdlib/tst-strtod-round-data
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@@ -265,3 +265,15 @@
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1.000000000000000000000000000000000385185988877447170611195588516985463707620329643077639047987759113311767578125
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1.0000000000000000000000000000000001925929944387235853055977942584927318538101648215388195239938795566558837890625
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1.00000000000000000000000000000000009629649721936179265279889712924636592690508241076940976199693977832794189453125
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+0x30000002222225p-1077
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+0x0.7fffffffffffeap-1022
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+0x0.7fffffffffffe9p-1022
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+0x0.7ffffd4p-126
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+0x0.7ffffffffffffffd4p-16382
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+0x0.7ffffffffffffffd4p-16383
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+0x0.7ffffffffffffffffffffffffffeap-16382
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+0x0.7000004p-126
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+0x0.70000000000002p-1022
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+0x0.70000000000000004p-16382
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+0x0.70000000000000004p-16383
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+0x0.70000000000000000000000000002p-16382
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diff --git a/stdlib/tst-strtod-round-data.h b/stdlib/tst-strtod-round-data.h
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index 13e62dd2b0588a16..ed50eb2537bc175c 100644
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--- a/stdlib/tst-strtod-round-data.h
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+++ b/stdlib/tst-strtod-round-data.h
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@@ -15437,4 +15437,376 @@ static const struct test tests[] = {
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0x1p+0, false, false,
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0x1p+0, false, false,
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0x1.0000000000000000000000000001p+0, false, false),
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+ TEST ("0x30000002222225p-1077",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x1.800000111111p-1024, false, true,
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+ 0x1.8000001111114p-1024, false, true,
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+ 0x1.800000111111p-1024, false, true,
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+ 0x1.8000001111114p-1024, false, true,
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+ true,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ true,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ false,
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+ 0x1.800000111111p-1024, false, true,
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+ 0x1.8000001111114p-1024, false, true,
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+ 0x1.800000111111p-1024, false, true,
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+ 0x1.8000001111114p-1024, false, true,
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+ true,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false,
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+ 0x1.80000011111128p-1024, false, false),
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+ TEST ("0x0.7fffffffffffeap-1022",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ true,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ true,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ false,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ true,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false,
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+ 0x1.ffffffffffffa8p-1024, false, false),
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+ TEST ("0x0.7fffffffffffe9p-1022",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ true,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ true,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ false,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ 0x1.ffffffffffff8p-1024, false, true,
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+ 0x1.ffffffffffffcp-1024, false, true,
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+ true,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false,
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+ 0x1.ffffffffffffa4p-1024, false, false),
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+ TEST ("0x0.7ffffd4p-126",
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+ false,
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+ 0x1.fffffp-128, false, true,
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+ 0x1.fffff8p-128, false, true,
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+ 0x1.fffffp-128, false, true,
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+ 0x1.fffff8p-128, false, true,
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+ true,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ true,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ true,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ true,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ true,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false,
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+ 0x1.fffff5p-128, false, false),
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+ TEST ("0x0.7ffffffffffffffd4p-16382",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ false,
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+ 0x1.fffffffffffffffp-16384, false, true,
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+ 0x1.fffffffffffffff8p-16384, false, true,
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+ 0x1.fffffffffffffffp-16384, false, true,
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+ 0x1.fffffffffffffff8p-16384, false, true,
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+ false,
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+ 0x1.fffffffffffffff4p-16384, false, true,
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+ 0x1.fffffffffffffff4p-16384, false, true,
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+ 0x1.fffffffffffffff4p-16384, false, true,
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+ 0x1.fffffffffffffff8p-16384, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ true,
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+ 0x1.fffffffffffffff5p-16384, false, false,
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+ 0x1.fffffffffffffff5p-16384, false, false,
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+ 0x1.fffffffffffffff5p-16384, false, false,
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+ 0x1.fffffffffffffff5p-16384, false, false),
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+ TEST ("0x0.7ffffffffffffffd4p-16383",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ false,
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+ 0xf.ffffffffffffff8p-16388, false, true,
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+ 0xf.ffffffffffffff8p-16388, false, true,
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+ 0xf.ffffffffffffff8p-16388, false, true,
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+ 0x1p-16384, false, true,
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+ false,
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+ 0xf.ffffffffffffff8p-16388, false, true,
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+ 0xf.ffffffffffffffcp-16388, false, true,
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+ 0xf.ffffffffffffff8p-16388, false, true,
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+ 0xf.ffffffffffffffcp-16388, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ true,
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+ 0xf.ffffffffffffffa8p-16388, false, false,
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+ 0xf.ffffffffffffffa8p-16388, false, false,
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+ 0xf.ffffffffffffffa8p-16388, false, false,
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+ 0xf.ffffffffffffffa8p-16388, false, false),
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+ TEST ("0x0.7ffffffffffffffffffffffffffeap-16382",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ false,
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+ 0x1.fffffffffffffff8p-16384, false, true,
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+ 0x2p-16384, false, true,
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+ 0x1.fffffffffffffff8p-16384, false, true,
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+ 0x2p-16384, false, true,
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+ false,
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+ 0x1.fffffffffffffffcp-16384, false, true,
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+ 0x2p-16384, false, true,
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+ 0x1.fffffffffffffffcp-16384, false, true,
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+ 0x2p-16384, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ false,
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+ 0x1.fffffffffffffffffffffffffff8p-16384, false, true,
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+ 0x1.fffffffffffffffffffffffffffcp-16384, false, true,
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+ 0x1.fffffffffffffffffffffffffff8p-16384, false, true,
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+ 0x1.fffffffffffffffffffffffffffcp-16384, false, true),
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+ TEST ("0x0.7000004p-126",
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+ false,
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+ 0x1.cp-128, false, true,
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+ 0x1.cp-128, false, true,
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+ 0x1.cp-128, false, true,
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+ 0x1.c00008p-128, false, true,
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+ true,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ true,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ true,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ true,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ true,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false,
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+ 0x1.c00001p-128, false, false),
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+ TEST ("0x0.70000000000002p-1022",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x1.cp-1024, false, true,
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+ 0x1.cp-1024, false, true,
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+ 0x1.cp-1024, false, true,
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+ 0x1.c000000000004p-1024, false, true,
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+ true,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ true,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ false,
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+ 0x1.cp-1024, false, true,
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+ 0x1.cp-1024, false, true,
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+ 0x1.cp-1024, false, true,
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+ 0x1.c000000000004p-1024, false, true,
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+ true,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false,
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+ 0x1.c0000000000008p-1024, false, false),
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+ TEST ("0x0.70000000000000004p-16382",
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x8p-152, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ false,
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+ 0x1.cp-16384, false, true,
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+ 0x1.cp-16384, false, true,
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+ 0x1.cp-16384, false, true,
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+ 0x1.c000000000000008p-16384, false, true,
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+ false,
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+ 0x1.cp-16384, false, true,
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+ 0x1.cp-16384, false, true,
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+ 0x1.cp-16384, false, true,
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+ 0x1.c000000000000004p-16384, false, true,
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+ false,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x0p+0, false, true,
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+ 0x4p-1076, false, true,
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+ true,
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+ 0x1.c000000000000001p-16384, false, false,
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+ 0x1.c000000000000001p-16384, false, false,
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+ 0x1.c000000000000001p-16384, false, false,
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+ 0x1.c000000000000001p-16384, false, false),
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+ TEST ("0x0.70000000000000004p-16383",
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+ false,
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+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x8p-152, false, true,
|
|
+ false,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x4p-1076, false, true,
|
|
+ false,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xe.000000000000008p-16388, false, true,
|
|
+ false,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xep-16388, false, true,
|
|
+ 0xe.000000000000004p-16388, false, true,
|
|
+ false,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x4p-1076, false, true,
|
|
+ true,
|
|
+ 0xe.0000000000000008p-16388, false, false,
|
|
+ 0xe.0000000000000008p-16388, false, false,
|
|
+ 0xe.0000000000000008p-16388, false, false,
|
|
+ 0xe.0000000000000008p-16388, false, false),
|
|
+ TEST ("0x0.70000000000000000000000000002p-16382",
|
|
+ false,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x8p-152, false, true,
|
|
+ false,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x4p-1076, false, true,
|
|
+ false,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.c000000000000008p-16384, false, true,
|
|
+ false,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.c000000000000004p-16384, false, true,
|
|
+ false,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x0p+0, false, true,
|
|
+ 0x4p-1076, false, true,
|
|
+ false,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.cp-16384, false, true,
|
|
+ 0x1.c000000000000000000000000004p-16384, false, true),
|
|
};
|