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46 lines
1.4 KiB
C
46 lines
1.4 KiB
C
/* this header file comes from libowfat, http://www.fefe.de/libowfat/ */
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#ifndef _SAFEMULT_H
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#define _SAFEMULT_H
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#include "uint16.h"
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#include "uint32.h"
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#include "uint64.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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#if defined(__GNUC__) && (__GNUC__ >= 5)
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/* for historical reasons, the mult interface uses 0 for failure and 1
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* for success, while the builtins (and my own addition and
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* subtraction routines in rangecheck.h) do it the other way around. */
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extern inline int umult16(uint16 a,uint16 b,uint16* c) { return !__builtin_mul_overflow(a,b,c); }
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extern inline int imult16( int16 a, int16 b, int16* c) { return !__builtin_mul_overflow(a,b,c); }
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extern inline int umult32(uint32 a,uint32 b,uint32* c) { return !__builtin_mul_overflow(a,b,c); }
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extern inline int imult32( int32 a, int32 b, int32* c) { return !__builtin_mul_overflow(a,b,c); }
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extern inline int umult64(uint64 a,uint64 b,uint64* c) { return !__builtin_mul_overflow(a,b,c); }
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extern inline int imult64( int64 a, int64 b, int64* c) { return !__builtin_mul_overflow(a,b,c); }
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#else
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/* return 0 for overflow, 1 for ok */
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int umult16(uint16 a,uint16 b,uint16* c);
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int imult16( int16 a, int16 b, int16* c);
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int umult32(uint32 a,uint32 b,uint32* c);
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int imult32( int32 a, int32 b, int32* c);
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int umult64(uint64 a,uint64 b,uint64* c);
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int imult64( int64 a, int64 b, int64* c);
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif
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