short_float.h

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// ----------------------------------------------------------------------------
// openCARP is an open cardiac electrophysiology simulator.
//
// Copyright (C) 2020 openCARP project
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// If automatically generated, keep above
// comment as first line in file.
#ifndef __SHORT_FLOAT_H__
#define __SHORT_FLOAT_H__
 
/*
ftp://ftp.fox-toolkit.org/pub/fasthalffloatconversion.pdf
 
Fast Half Float Conversions
Jeroen van der Zijp
November 2008
(Revised September 2010)
 
Use the dumpTables code to generate the corresponding C file.
*/
 
 
#include <cstdint>
 
#define SHORTVEC(V,A,B,C) short_float V[3] = {shortFromFloat(A),shortFromFloat(B),shortFromFloat(C)}
#define SHORT_VCP(V,A) {float *a=(float *)(A);short_float *v=(short_float *)(V); \
                         v[0]=shortFromFloat(a[0]);\
                         v[1]=shortFromFloat(a[1]);\
                         v[2]=shortFromFloat(a[2]);}
#define FLOAT_VCP(V,A) {float *v=(float *)(V);short_float *a=(short_float *)(A); \
                         v[0]=floatFromShort(a[0]);\
                         v[1]=floatFromShort(a[1]);\
                         v[2]=floatFromShort(a[2]);}
 
extern const uint16_t basetable[512];
extern const uint16_t shifttable[512];
extern const uint32_t mantissatable[2048];
extern const uint16_t offsettable[64];
extern const uint32_t exponenttable[64];
 
typedef uint16_t short_float;
 
static inline short_float shortFromFloat(const float external_ff) {
  union {
    float as_float;
    uint32_t as_uint32;
  } c;
  c.as_float = external_ff;
  return basetable[(c.as_uint32>>23)&0x1ff]+((c.as_uint32&0x007fffff)>>shifttable[(c.as_uint32>>23)&0x1ff]);
}
 
static inline float floatFromShort(const short_float h) {
  union {
    float as_float;
    uint32_t as_uint32;
  } c;
  c.as_uint32 = mantissatable[offsettable[h>>10]+(h&0x3ff)]+exponenttable[h>>10];
  return c.as_float;
}
 
inline short_float negShort( short_float x ) {
  return x ^= 1U << 15;
}
 
#define SHORT_FLOAT_MACHINE_EPS 0.0009765625
 
#endif