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+ added IEEE_NAN

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+ added IEEE_INF
+ version string
This commit is contained in:
Rob Tillaart 2013-09-30 17:16:58 +02:00
parent ca8694992e
commit 00877f4951
1 changed files with 53 additions and 5 deletions
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58
libraries/IEEE754tools/IEEE754tools.h
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@ -1,7 +1,7 @@
//
// FILE: IEEE754tools.h
// AUTHOR: Rob Tillaart
// VERSION: 0.1.00
// VERSION: 0.1.01
// PURPOSE: IEEE754 tools
//
// http://playground.arduino.cc//Main/IEEE754tools
@ -9,6 +9,8 @@
// Released to the public domain
// not tested, use with care
//
// 0.1.01 added IEEE_NAN, IEEE_INF tests + version string
// 0.1.00 initial version
#ifndef IEEE754tools_h
#define IEEE754tools_h
@ -20,8 +22,10 @@
#include "WProgram.h"
#endif
#define IEEE754_VERSION "0.1.01"
// (un)comment lines to configure functionality / size
//#define IEEE754_ENABLE_MSB
//#define IEEE754_ENABLE_MSB // +78 bytes
#define IEEE754_ENABLE_DUMP
// IEEE754 float layout;
@ -132,11 +136,9 @@ void float2DoublePacked(float number, byte* bar, int byteOrder=LSBFIRST)
#endif
}
//
// converts a packed array of bytes into a 32bit float.
// there can be an exponent overflow
// the mantisse is truncated to 23 bits.
//
float doublePacked2Float(byte* bar, int byteOrder=LSBFIRST)
{
_FLOATCONV fl;
@ -174,9 +176,55 @@ float doublePacked2Float(byte* bar, int byteOrder=LSBFIRST)
return fl.f;
}
// ~1.7x faster
int IEEE_NAN(float number)
{
return (* ((uint16_t*) &number + 1) ) == 0x7FC0;
}
// ~3.4x faster
int IEEE_INF(float number)
{
uint8_t* x = ((uint8_t*) &number);
if (*(x+2) != 0x80) return 0;
if (*(x+3) == 0x7F) return 1;
if (*(x+3) == 0xFF) return -1;
return 0;
}
// for the real speed freaks, the next two
bool IEEE_PosINF(float number)
{
return (* ((uint16_t*) &number + 1) ) == 0x7F80;
}
bool IEEE_NegINF(float number)
{
return (* ((uint16_t*) &number + 1) ) == 0xFF80;
}
// WARNING no overflow detection in the SHIFT (factor 3.5)
float IEEE_SHIFT_LEFT(float number, uint8_t n)
{
_FLOATCONV fl;
fl.f = number;
fl.p.e += n;
return fl.f;
}
float IEEE_SHIFT_RIGHT(float number, uint8_t n)
{
_FLOATCONV fl;
fl.f = number;
fl.p.e -= n;
return fl.f;
}
//
// NOT TESTED FUNCTIONS
//
//
uint8_t getSign(float number)
{
IEEEfloat* x = (IEEEfloat*) ((void*)&number);