src/gallium/auxiliary/util/u_half.h

   1 #ifndef U_HALF_H
   2 #define U_HALF_H
   3
   4 #include "pipe/p_compiler.h"
   5 #include "util/u_math.h"
   6
   7 #ifdef __cplusplus
   8 extern "C" {
   9 #endif
  10
  11 extern uint32_t util_half_to_float_mantissa_table[2048];
  12 extern uint32_t util_half_to_float_exponent_table[64];
  13 extern uint32_t util_half_to_float_offset_table[64];
  14 extern uint16_t util_float_to_half_base_table[512];
  15 extern uint8_t util_float_to_half_shift_table[512];
  16
  17 /*
  18  * Note that if the half float is a signaling NaN, the x87 FPU will turn
  19  * it into a quiet NaN immediately upon loading into a float.
  20  *
  21  * Additionally, denormals may be flushed to zero.
  22  *
  23  * To avoid this, use the floatui functions instead of the float ones
  24  * when just doing conversion rather than computation on the resulting
  25  * floats.
  26  */
  27
  28 static INLINE uint32_t
  29 util_half_to_floatui(half h)
  30 {
  31    unsigned exp = h >> 10;
  32    return util_half_to_float_mantissa_table[util_half_to_float_offset_table[exp] + (h & 0x3ff)] + util_half_to_float_exponent_table[exp];
  33 }
  34
  35 static INLINE float
  36 util_half_to_float(half h)
  37 {
  38    union fi r;
  39    r.ui = util_half_to_floatui(h);
  40    return r.f;
  41 }
  42
  43 static INLINE half
  44 util_floatui_to_half(uint32_t v)
  45 {
  46    unsigned signexp = v >> 23;
  47    return util_float_to_half_base_table[signexp] + ((v & 0x007fffff) >> util_float_to_half_shift_table[signexp]);
  48 }
  49
  50 static INLINE half
  51 util_float_to_half(float f)
  52 {
  53    union fi i;
  54    i.f = f;
  55    return util_floatui_to_half(i.ui);
  56 }
  57
  58 #ifdef __cplusplus
  59 }
  60 #endif
  61
  62 #endif /* U_HALF_H */
  63