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bd1fd12b07
runtime/mercury_float.h: Define MR_float_to_word and MR_word_to_float as macros using GCC's cast to union extension with clang, since it also supports that extension.
217 lines
7.8 KiB
C
217 lines
7.8 KiB
C
/*
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** Copyright (C) 1995-1997, 1999-2002, 2007, 2011 The University of Melbourne.
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** This file may only be copied under the terms of the GNU Library General
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** Public License - see the file COPYING.LIB in the Mercury distribution.
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*/
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/* mercury_float.h - floating point handling */
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#ifndef MERCURY_FLOAT_H
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#define MERCURY_FLOAT_H
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#include "mercury_conf.h" /* for MR_BOXED_FLOAT, MR_CONSERVATIVE_GC */
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#include "mercury_types.h" /* for `MR_Word' */
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#include "mercury_std.h" /* for `MR_bool' */
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#ifdef MR_USE_SINGLE_PREC_FLOAT
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typedef float MR_Float;
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#define MR_FLT_MIN_PRECISION 7
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#define MR_FLT_FMT "%f"
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/* We assume that sizeof(float) <= sizeof(MR_Word). */
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#undef MR_BOXED_FLOAT
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#else
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typedef double MR_Float;
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#define MR_FLT_MIN_PRECISION 15
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#define MR_FLT_FMT "%lf"
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#endif
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#define MR_FLT_MAX_PRECISION (MR_FLT_MIN_PRECISION + 2)
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#define MR_FLOAT_WORDS ((sizeof(MR_Float) + sizeof(MR_Word) - 1) \
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/ sizeof(MR_Word))
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/*
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** MR_Float_Aligned and #pragma pack are used convince the C compiler to lay
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** out structures containing MR_Float members as expected by the Mercury
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** compiler, without additional padding or packing.
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**
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** For MSVC, __declspec(align) only increases alignment, e.g. for single
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** precision floats on 64-bit platforms. #pragma pack is required to
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** reduce packing size, e.g. double precision floats on 32-bit platform.
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*/
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#if defined(MR_GNUC) || defined(MR_CLANG)
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typedef MR_Float MR_Float_Aligned __attribute__((aligned(sizeof(MR_Word))));
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#elif defined(MR_MSVC)
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typedef __declspec(align(MR_BYTES_PER_WORD)) MR_Float MR_Float_Aligned;
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#else
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typedef MR_Float MR_Float_Aligned;
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#endif
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#ifdef MR_BOXED_FLOAT
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#define MR_word_to_float(w) (* (MR_Float *) (w))
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#ifdef MR_CONSERVATIVE_GC
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#define MR_float_to_word(f) \
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( \
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MR_hp_alloc_atomic_msg(MR_FLOAT_WORDS, \
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(MR_AllocSiteInfoPtr) MR_ALLOC_SITE_FLOAT, NULL), \
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* (MR_Float *) (void *) (MR_hp - MR_FLOAT_WORDS) = (f), \
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/* return */ (MR_Word) (MR_hp - MR_FLOAT_WORDS) \
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)
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#define MR_make_hp_float_aligned() ((void)0)
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#else
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/*
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** We need to ensure that what we allocated on the heap is properly
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** aligned for a floating-point value, by rounding MR_hp up to the
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** nearest float-aligned boundary.
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** XXX This code assumes that sizeof(MR_Float) is a power of two,
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** and not greater than 2 * sizeof(MR_Word).
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*/
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#define MR_make_hp_float_aligned() \
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( (MR_Word) MR_hp & (sizeof(MR_Float) - 1) ? \
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MR_hp_alloc_atomic_msg(1, MR_ALLOC_SITE_FLOAT, NULL) \
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: \
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(void)0 \
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)
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#define MR_float_to_word(f) \
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( \
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MR_make_hp_float_aligned(), \
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MR_hp_alloc_atomic_msg(MR_FLOAT_WORDS, MR_ALLOC_SITE_FLOAT, NULL), \
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* (MR_Float *) (void *)(MR_hp - MR_FLOAT_WORDS) = (f), \
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/* return */ (MR_Word) (MR_hp - MR_FLOAT_WORDS) \
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)
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#endif
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#ifdef MR_GNUC
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#define MR_float_const(f) ({ static const MR_Float d = f; (MR_Word) &d; })
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#else
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#define MR_float_const(f) MR_float_to_word(f) /* inefficient */
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#endif
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/*
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** MR_BOXED_FLOAT is never defined if using single-precision floats,
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** so MR_Float must be double.
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*/
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union MR_Float_Dword {
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MR_Float f;
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MR_Word w[2];
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};
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#if defined(MR_GNUC) || defined(MR_CLANG)
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#define MR_float_word_bits(F, I) \
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(((union MR_Float_Dword) (MR_Float) (F)).w[(I)])
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#else
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MR_EXTERN_INLINE MR_Word
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MR_float_word_bits(MR_Float f, MR_Integer n);
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MR_EXTERN_INLINE MR_Word
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MR_float_word_bits(MR_Float f, MR_Integer n)
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{
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union MR_Float_Dword __ffdw;
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__ffdw.f = f;
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return __ffdw.w[n];
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}
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#endif
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#if defined(MR_DEBUG_DWORD_ALIGNMENT) && \
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(defined(MR_GNUC) || defined(MR_CLANG))
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#define MR_dword_ptr(ptr) \
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({ \
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MR_Word __addr = (MR_Word) (ptr); \
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assert((__addr % 8) == 0); \
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/* return */ (void *) __addr; \
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})
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#else
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#define MR_dword_ptr(ptr) ((void *) (ptr))
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#endif
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#define MR_float_from_dword_ptr(ptr) \
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(((union MR_Float_Dword *) (ptr))->f)
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#if defined(MR_GNUC) || defined(MR_CLANG)
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#define MR_float_from_dword(w0, w1) \
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({ \
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union MR_Float_Dword __ffdw; \
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__ffdw.w[0] = (MR_Word) (w0); \
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__ffdw.w[1] = (MR_Word) (w1); \
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__ffdw.f; \
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})
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#else
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#define MR_float_from_dword(w0, w1) \
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MR_float_from_dword_func((MR_Word)(w0), (MR_Word)(w1))
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MR_EXTERN_INLINE MR_Float
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MR_float_from_dword_func(MR_Word w0, MR_Word w1);
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MR_EXTERN_INLINE MR_Float
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MR_float_from_dword_func(MR_Word w0, MR_Word w1)
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{
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union MR_Float_Dword __ffdw;
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__ffdw.w[0] = (MR_Word) (w0);
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__ffdw.w[1] = (MR_Word) (w1);
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return __ffdw.f;
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}
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#endif
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#else /* not MR_BOXED_FLOAT */
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/* unboxed float means we can assume sizeof(MR_Float) <= sizeof(MR_Word) */
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#define MR_make_hp_float_aligned() ((void)0)
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union MR_Float_Word {
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MR_Float f;
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MR_Word w;
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};
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#define MR_float_const(f) MR_float_to_word(f)
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#if defined(MR_GNUC) || defined(MR_CLANG)
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/*
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** GNU C allows you to cast to a union type.
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** clang also provides this extension.
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*/
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#define MR_float_to_word(f) (__extension__ \
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((union MR_Float_Word)(MR_Float)(f)).w)
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#define MR_word_to_float(w) (__extension__ \
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((union MR_Float_Word)(MR_Word)(w)).f)
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#else /* not MR_GNUC or MR_CLANG */
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static MR_Word MR_float_to_word(MR_Float f)
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{ union MR_Float_Word tmp; tmp.f = f; return tmp.w; }
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static MR_Float MR_word_to_float(MR_Word w)
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{ union MR_Float_Word tmp; tmp.w = w; return tmp.f; }
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#endif /* not MR_GNUC or MR_CLANG */
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#endif /* not MR_BOXED_FLOAT */
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/*
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** The size of the buffer to pass to MR_sprintf_float.
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**
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** Longest possible string for %#.*g format is `-n.nnnnnnE-mmmm', which
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** has size PRECISION + MAX_EXPONENT_DIGITS + 5 (for the `-', `.', `E',
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** '-', and '\\0'). PRECISION is at most 20, and MAX_EXPONENT_DIGITS is
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** at most 5, so we need at most 30 chars. 80 is way more than enough.
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*/
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#define MR_SPRINTF_FLOAT_BUF_SIZE 80
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#define MR_float_to_string(Float, String, alloc_id) \
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do { \
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char buf[MR_SPRINTF_FLOAT_BUF_SIZE]; \
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MR_sprintf_float(buf, Float); \
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MR_make_aligned_string_copy_msg(Str, buf, (alloc_id)); \
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} while (0)
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void MR_sprintf_float(char *buf, MR_Float f);
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MR_Integer MR_hash_float(MR_Float);
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MR_bool MR_is_nan(MR_Float);
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MR_bool MR_is_inf(MR_Float);
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#endif /* not MERCURY_FLOAT_H */
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