gistfile1.txt

#include <emmintrin.h>
#include <stdio.h>

int main(void)
{
   static float buf[] __attribute__((aligned(16))) = {0x4000, 0x3000, 0x2000, 0x1000};
   printf("Before: %f, %f, %f, %f\n", buf[0], buf[1], buf[2], buf[3]);

   __m128i reg = _mm_load_si128((__m128i*)buf);

   __m128i exp = _mm_and_si128(reg, _mm_set1_epi32(0x7f800000));
   __m128i mantissa = _mm_and_si128(reg, _mm_set1_epi32(0x807fffff));

   exp = _mm_and_si128(_mm_sub_epi32(exp, _mm_set1_epi32(15 << 23)), _mm_set1_epi32(0x7f800000));

   _mm_store_ps(buf, (__m128)_mm_or_si128(exp, mantissa));

   printf("After: %f, %f, %f, %f\n", buf[0], buf[1], buf[2], buf[3]);
}