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