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32 lines
527 B
C
32 lines
527 B
C
#if defined(__GNUC__) && (__GNUC__ >= 5)
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#include "uint16.h"
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int umult16(uint16 a,uint16 b,uint16* c) { return !__builtin_mul_overflow(a,b,c); }
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#else
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#include "safemult.h"
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int umult16(uint16 a,uint16 b,uint16* c) {
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unsigned long x=(unsigned long)a*b;
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if (x>0xffff) return 0;
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*c=x&0xffff;
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return 1;
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}
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#endif
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#ifdef UNITTEST
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#include <assert.h>
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int main() {
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uint16 a;
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assert(umult16(7,10000,&a)==0);
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assert(umult16(5,10,&a)==1 && a==50);
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assert(umult16(6,10000,&a)==1 && a==60000);
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return 0;
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}
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#endif
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