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picasso_frontend: Get rid of undefined behavior

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Type-punning via a union is well-defined in C (specifically C99 and onwards), but not C++
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Lioncash 2017-12-27 22:53:47 -05:00 committed by fincs
parent 299c35d6fc
commit d1a1c0a011
1 changed files with 2 additions and 8 deletions
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10
source/picasso_frontend.cpp
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@ -1,19 +1,13 @@
#include "picasso.h" #include "picasso.h"
static inline uint32_t floatrawbits(float f)
{
union { float f; uint32_t i; } s;
s.f = f;
return s.i;
}
// f24 has: // f24 has:
// - 1 sign bit // - 1 sign bit
// - 7 exponent bits // - 7 exponent bits
// - 16 mantissa bits // - 16 mantissa bits
uint32_t f32tof24(float f) uint32_t f32tof24(float f)
{ {
uint32_t i = floatrawbits(f); uint32_t i;
std::memcpy(&i, &f, sizeof(f));
uint32_t mantissa = (i << 9) >> 9; uint32_t mantissa = (i << 9) >> 9;
int32_t exponent = (i << 1) >> 24; int32_t exponent = (i << 1) >> 24;