107 lines
2.1 KiB
C
107 lines
2.1 KiB
C
/* go-type-float.c -- hash and equality float functions.
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Copyright 2012 The Go Authors. All rights reserved.
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Use of this source code is governed by a BSD-style
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license that can be found in the LICENSE file. */
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#include "runtime.h"
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#include "go-type.h"
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/* The 32-bit and 64-bit types. */
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typedef unsigned int SItype __attribute__ ((mode (SI)));
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typedef unsigned int DItype __attribute__ ((mode (DI)));
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/* Hash function for float types. */
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uintptr_t
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__go_type_hash_float (const void *vkey, uintptr_t key_size)
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{
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if (key_size == 4)
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{
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union
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{
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unsigned char a[4];
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float f;
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SItype si;
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} uf;
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float f;
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__builtin_memcpy (uf.a, vkey, 4);
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f = uf.f;
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if (__builtin_isinff (f) || f == 0)
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return 0;
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/* NaN != NaN, so the hash code of a NaN is irrelevant. Make it
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random so that not all NaNs wind up in the same place. */
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if (__builtin_isnanf (f))
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return runtime_fastrand1 ();
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return (uintptr_t) uf.si;
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}
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else if (key_size == 8)
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{
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union
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{
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unsigned char a[8];
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double d;
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DItype di;
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} ud;
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double d;
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__builtin_memcpy (ud.a, vkey, 8);
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d = ud.d;
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if (__builtin_isinf (d) || d == 0)
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return 0;
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if (__builtin_isnan (d))
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return runtime_fastrand1 ();
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return (uintptr_t) ud.di;
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}
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else
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runtime_throw ("__go_type_hash_float: invalid float size");
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}
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/* Equality function for float types. */
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_Bool
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__go_type_equal_float (const void *vk1, const void *vk2, uintptr_t key_size)
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{
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if (key_size == 4)
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{
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union
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{
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unsigned char a[4];
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float f;
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} uf;
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float f1;
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float f2;
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__builtin_memcpy (uf.a, vk1, 4);
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f1 = uf.f;
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__builtin_memcpy (uf.a, vk2, 4);
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f2 = uf.f;
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return f1 == f2;
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}
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else if (key_size == 8)
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{
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union
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{
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unsigned char a[8];
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double d;
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DItype di;
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} ud;
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double d1;
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double d2;
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__builtin_memcpy (ud.a, vk1, 8);
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d1 = ud.d;
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__builtin_memcpy (ud.a, vk2, 8);
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d2 = ud.d;
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return d1 == d2;
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}
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else
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runtime_throw ("__go_type_equal_float: invalid float size");
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}
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