2011-06-11 17:16:53 +04:00
|
|
|
/*============================================================================
|
|
|
|
This C source file is part of the SoftFloat IEC/IEEE Floating-point Arithmetic
|
|
|
|
Package, Release 2b.
|
|
|
|
|
|
|
|
Written by John R. Hauser. This work was made possible in part by the
|
|
|
|
International Computer Science Institute, located at Suite 600, 1947 Center
|
|
|
|
Street, Berkeley, California 94704. Funding was partially provided by the
|
|
|
|
National Science Foundation under grant MIP-9311980. The original version
|
|
|
|
of this code was written as part of a project to build a fixed-point vector
|
|
|
|
processor in collaboration with the University of California at Berkeley,
|
|
|
|
overseen by Profs. Nelson Morgan and John Wawrzynek. More information
|
|
|
|
is available through the Web page `http://www.cs.berkeley.edu/~jhauser/
|
|
|
|
arithmetic/SoftFloat.html'.
|
|
|
|
|
|
|
|
THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort has
|
|
|
|
been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT TIMES
|
|
|
|
RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO PERSONS
|
|
|
|
AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ALL LOSSES,
|
|
|
|
COSTS, OR OTHER PROBLEMS THEY INCUR DUE TO THE SOFTWARE, AND WHO FURTHERMORE
|
|
|
|
EFFECTIVELY INDEMNIFY JOHN HAUSER AND THE INTERNATIONAL COMPUTER SCIENCE
|
|
|
|
INSTITUTE (possibly via similar legal warning) AGAINST ALL LOSSES, COSTS, OR
|
|
|
|
OTHER PROBLEMS INCURRED BY THEIR CUSTOMERS AND CLIENTS DUE TO THE SOFTWARE.
|
|
|
|
|
|
|
|
Derivative works are acceptable, even for commercial purposes, so long as
|
|
|
|
(1) the source code for the derivative work includes prominent notice that
|
|
|
|
the work is derivative, and (2) the source code includes prominent notice with
|
|
|
|
these four paragraphs for those parts of this code that are retained.
|
|
|
|
=============================================================================*/
|
|
|
|
|
|
|
|
/*============================================================================
|
|
|
|
* Adapted for Bochs (x86 achitecture simulator) by
|
|
|
|
* Stanislav Shwartsman [sshwarts at sourceforge net]
|
|
|
|
* ==========================================================================*/
|
|
|
|
|
|
|
|
#include "softfloat.h"
|
|
|
|
|
|
|
|
#ifdef FLOAT16
|
|
|
|
|
|
|
|
#include "softfloat-round-pack.h"
|
|
|
|
#include "softfloat-specialize.h"
|
|
|
|
#include "softfloat-macros.h"
|
|
|
|
|
|
|
|
/*----------------------------------------------------------------------------
|
|
|
|
| Determine half-precision floating-point number class
|
|
|
|
*----------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
float_class_t float16_class(float16 a)
|
|
|
|
{
|
|
|
|
Bit16s aExp = extractFloat16Exp(a);
|
|
|
|
Bit16u aSig = extractFloat16Frac(a);
|
|
|
|
int aSign = extractFloat16Sign(a);
|
|
|
|
|
|
|
|
if(aExp == 0x1F) {
|
|
|
|
if (aSig == 0)
|
|
|
|
return (aSign) ? float_negative_inf : float_positive_inf;
|
|
|
|
|
2014-03-10 01:42:11 +04:00
|
|
|
return (aSig & 0x200) ? float_QNaN : float_SNaN;
|
2011-06-11 17:16:53 +04:00
|
|
|
}
|
|
|
|
|
|
|
|
if(aExp == 0) {
|
|
|
|
if (aSig == 0) return float_zero;
|
|
|
|
return float_denormal;
|
|
|
|
}
|
|
|
|
|
|
|
|
return float_normalized;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*----------------------------------------------------------------------------
|
|
|
|
| Returns the result of converting the half-precision floating-point value
|
|
|
|
| `a' to the single-precision floating-point format. The conversion is
|
|
|
|
| performed according to the IEC/IEEE Standard for Binary Floating-Point
|
|
|
|
| Arithmetic.
|
|
|
|
*----------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
float32 float16_to_float32(float16 a, float_status_t &status)
|
|
|
|
{
|
|
|
|
Bit16u aSig = extractFloat16Frac(a);
|
|
|
|
Bit16s aExp = extractFloat16Exp(a);
|
|
|
|
int aSign = extractFloat16Sign(a);
|
|
|
|
|
|
|
|
if (aExp == 0x1F) {
|
|
|
|
if (aSig) return commonNaNToFloat32(float16ToCommonNaN(a, status));
|
|
|
|
return packFloat32(aSign, 0xFF, 0);
|
|
|
|
}
|
|
|
|
if (aExp == 0) {
|
2012-06-05 15:36:50 +04:00
|
|
|
// ignore denormals_are_zeros flag
|
2011-06-11 17:16:53 +04:00
|
|
|
if (aSig == 0) return packFloat32(aSign, 0, 0);
|
|
|
|
float_raise(status, float_flag_denormal);
|
|
|
|
normalizeFloat16Subnormal(aSig, &aExp, &aSig);
|
|
|
|
--aExp;
|
|
|
|
}
|
|
|
|
|
|
|
|
return packFloat32(aSign, aExp + 0x70, ((Bit32u) aSig)<<13);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*----------------------------------------------------------------------------
|
|
|
|
| Returns the result of converting the single-precision floating-point value
|
|
|
|
| `a' to the half-precision floating-point format. The conversion is
|
|
|
|
| performed according to the IEC/IEEE Standard for Binary Floating-Point
|
|
|
|
| Arithmetic.
|
|
|
|
*----------------------------------------------------------------------------*/
|
|
|
|
|
|
|
|
float16 float32_to_float16(float32 a, float_status_t &status)
|
|
|
|
{
|
|
|
|
Bit32u aSig = extractFloat32Frac(a);
|
|
|
|
Bit16s aExp = extractFloat32Exp(a);
|
|
|
|
int aSign = extractFloat32Sign(a);
|
|
|
|
|
|
|
|
if (aExp == 0xFF) {
|
|
|
|
if (aSig) return commonNaNToFloat16(float32ToCommonNaN(a, status));
|
|
|
|
return packFloat16(aSign, 0x1F, 0);
|
|
|
|
}
|
|
|
|
if (aExp == 0) {
|
2011-10-01 19:40:36 +04:00
|
|
|
if (get_denormals_are_zeros(status)) aSig = 0;
|
2011-06-11 17:16:53 +04:00
|
|
|
if (aSig == 0) return packFloat16(aSign, 0, 0);
|
|
|
|
float_raise(status, float_flag_denormal);
|
|
|
|
}
|
|
|
|
|
|
|
|
aSig = shift32RightJamming(aSig, 9);
|
|
|
|
Bit16u zSig = (Bit16u) aSig;
|
|
|
|
if (aExp || zSig) {
|
|
|
|
zSig |= 0x4000;
|
|
|
|
aExp -= 0x71;
|
|
|
|
}
|
|
|
|
|
|
|
|
return roundAndPackFloat16(aSign, aExp, zSig, status);
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif
|