mirror of https://github.com/tongzx/nt5src
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
406 lines
7.2 KiB
406 lines
7.2 KiB
/***
|
|
*ieee.c - ieee control and status routines
|
|
*
|
|
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
|
|
*
|
|
*Purpose:
|
|
* IEEE control and status routines.
|
|
*
|
|
*Revision History:
|
|
*
|
|
* 04-01-02 GDP Rewritten to use abstract control and status words
|
|
* 10-30-92 GDP _fpreset now resets saved fp context if called from a
|
|
* signal handler.
|
|
* 09-01-94 SKS Change include file from <nt.h> to <windows.h>
|
|
* 04-11-95 JWM _fpreset() now resets default precision.
|
|
* 05-10-96 BWT Fix POSIX build.
|
|
*
|
|
*/
|
|
|
|
#include <trans.h>
|
|
#include <float.h>
|
|
#include <windows.h>
|
|
#include <signal.h>
|
|
|
|
extern void _setdefaultprecision();
|
|
|
|
static unsigned int _abstract_sw(unsigned short sw);
|
|
static unsigned int _abstract_cw(unsigned short cw);
|
|
static unsigned short _hw_cw(unsigned int abstr);
|
|
|
|
|
|
/***
|
|
* _statusfp() -
|
|
*
|
|
*Purpose:
|
|
* return abstract fp status word
|
|
*
|
|
*Entry:
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _statusfp()
|
|
{
|
|
short status;
|
|
|
|
_asm {
|
|
fstsw status
|
|
}
|
|
return _abstract_sw(status);
|
|
}
|
|
|
|
|
|
/***
|
|
*_clearfp() -
|
|
*
|
|
*Purpose:
|
|
* return abstract status word and clear status
|
|
*
|
|
*Entry:
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _clearfp()
|
|
{
|
|
short status;
|
|
|
|
_asm {
|
|
fnstsw status
|
|
fnclex
|
|
}
|
|
|
|
return _abstract_sw(status);
|
|
}
|
|
|
|
|
|
|
|
/*** _control87
|
|
*() -
|
|
*
|
|
*Purpose:
|
|
* return and set abstract user fp control word
|
|
* can modify EM_DENORMAL mask
|
|
*
|
|
*Entry:
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _control87(unsigned int newctrl, unsigned int mask)
|
|
{
|
|
short oldCw;
|
|
short newCw;
|
|
unsigned int oldabs;
|
|
unsigned int newabs;
|
|
|
|
_asm {
|
|
fstcw oldCw
|
|
}
|
|
|
|
oldabs = _abstract_cw(oldCw);
|
|
|
|
newabs = (newctrl & mask) | (oldabs & ~mask);
|
|
|
|
newCw = _hw_cw(newabs);
|
|
|
|
_asm {
|
|
fldcw newCw
|
|
}
|
|
return newabs;
|
|
} /* _controlfp() */
|
|
|
|
|
|
/*** _controlfp
|
|
*() -
|
|
*
|
|
*Purpose:
|
|
* return and set abstract user fp control word
|
|
* cannot change denormal mask (ignores _EM_DENORMAL)
|
|
* This is done for portable IEEE behavior on all platforms
|
|
*
|
|
*Entry:
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _controlfp(unsigned int newctrl, unsigned int mask)
|
|
{
|
|
return _control87(newctrl, mask & ~_EM_DENORMAL);
|
|
}
|
|
|
|
|
|
|
|
|
|
/***
|
|
* _fpreset() - reset fp system
|
|
*
|
|
*Purpose:
|
|
* reset fp environment to the default state
|
|
* Also reset saved fp environment if invoked from a user's
|
|
* signal handler
|
|
*
|
|
*Entry:
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
#define TAG_ALL_EMPTY ((unsigned int) 0xffff);
|
|
|
|
void _fpreset()
|
|
{
|
|
#ifndef _POSIX_
|
|
PEXCEPTION_POINTERS excptrs = (PEXCEPTION_POINTERS) _pxcptinfoptrs;
|
|
#endif
|
|
|
|
_asm {
|
|
fninit
|
|
}
|
|
_setdefaultprecision(); // reset precision, usually down to 53 bits
|
|
#ifndef _POSIX_
|
|
if (excptrs &&
|
|
excptrs->ContextRecord->ContextFlags & CONTEXT_FLOATING_POINT) {
|
|
// _fpreset has been invoked by a signal handler which in turn
|
|
// has been invoked by the CRT filter routine. In this case
|
|
// the saved fp context should be cleared, so that the change take
|
|
// effect on continuation.
|
|
|
|
FLOATING_SAVE_AREA *pFloatSave = &excptrs->ContextRecord->FloatSave;
|
|
pFloatSave->StatusWord = 0;
|
|
pFloatSave->TagWord = TAG_ALL_EMPTY;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/***
|
|
* _abstract_cw() - abstract control word
|
|
*
|
|
*Purpose:
|
|
* produce a fp control word in abstracted (machine independent) form
|
|
*
|
|
*Entry:
|
|
* cw: machine control word
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _abstract_cw(unsigned short cw)
|
|
{
|
|
unsigned int abstr = 0;
|
|
|
|
|
|
//
|
|
// Set exception mask bits
|
|
//
|
|
|
|
if (cw & IEM_INVALID)
|
|
abstr |= _EM_INVALID;
|
|
if (cw & IEM_ZERODIVIDE)
|
|
abstr |= _EM_ZERODIVIDE;
|
|
if (cw & IEM_OVERFLOW)
|
|
abstr |= _EM_OVERFLOW;
|
|
if (cw & IEM_UNDERFLOW)
|
|
abstr |= _EM_UNDERFLOW;
|
|
if (cw & IEM_INEXACT)
|
|
abstr |= _EM_INEXACT;
|
|
if (cw & IEM_DENORMAL)
|
|
abstr |= _EM_DENORMAL;
|
|
|
|
//
|
|
// Set rounding mode
|
|
//
|
|
|
|
switch (cw & IMCW_RC) {
|
|
case IRC_NEAR:
|
|
abstr |= _RC_NEAR;
|
|
break;
|
|
case IRC_UP:
|
|
abstr |= _RC_UP;
|
|
break;
|
|
case IRC_DOWN:
|
|
abstr |= _RC_DOWN;
|
|
break;
|
|
case IRC_CHOP:
|
|
abstr |= _RC_CHOP;
|
|
break;
|
|
}
|
|
|
|
//
|
|
// Set Precision mode
|
|
//
|
|
|
|
switch (cw & IMCW_PC) {
|
|
case IPC_64:
|
|
abstr |= _PC_64;
|
|
break;
|
|
case IPC_53:
|
|
abstr |= _PC_53;
|
|
break;
|
|
case IPC_24:
|
|
abstr |= _PC_24;
|
|
break;
|
|
}
|
|
|
|
|
|
//
|
|
// Infinity control (bit can be programmed but has no effect)
|
|
//
|
|
|
|
if (cw & IMCW_IC) {
|
|
abstr |= _IC_AFFINE;
|
|
}
|
|
|
|
return abstr;
|
|
}
|
|
|
|
|
|
/***
|
|
* _hw_cw() - h/w control word
|
|
*
|
|
*Purpose:
|
|
* produce a machine dependent fp control word
|
|
*
|
|
*
|
|
*Entry:
|
|
* abstr: abstract control word
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned short _hw_cw(unsigned int abstr)
|
|
{
|
|
//
|
|
// Set standard infinity and denormal control bits
|
|
//
|
|
|
|
unsigned short cw = 0;
|
|
|
|
//
|
|
// Set exception mask bits
|
|
//
|
|
|
|
if (abstr & _EM_INVALID)
|
|
cw |= IEM_INVALID;
|
|
if (abstr & _EM_ZERODIVIDE)
|
|
cw |= IEM_ZERODIVIDE;
|
|
if (abstr & _EM_OVERFLOW)
|
|
cw |= IEM_OVERFLOW;
|
|
if (abstr & _EM_UNDERFLOW)
|
|
cw |= IEM_UNDERFLOW;
|
|
if (abstr & _EM_INEXACT)
|
|
cw |= IEM_INEXACT;
|
|
if (abstr & _EM_DENORMAL)
|
|
cw |= IEM_DENORMAL;
|
|
|
|
//
|
|
// Set rounding mode
|
|
//
|
|
|
|
switch (abstr & _MCW_RC) {
|
|
case _RC_NEAR:
|
|
cw |= IRC_NEAR;
|
|
break;
|
|
case _RC_UP:
|
|
cw |= IRC_UP;
|
|
break;
|
|
case _RC_DOWN:
|
|
cw |= IRC_DOWN;
|
|
break;
|
|
case _RC_CHOP:
|
|
cw |= IRC_CHOP;
|
|
break;
|
|
}
|
|
|
|
//
|
|
// Set Precision mode
|
|
//
|
|
|
|
switch (abstr & _MCW_PC) {
|
|
case _PC_64:
|
|
cw |= IPC_64;
|
|
break;
|
|
case _PC_53:
|
|
cw |= IPC_53;
|
|
break;
|
|
case _PC_24:
|
|
cw |= IPC_24;
|
|
break;
|
|
}
|
|
|
|
|
|
//
|
|
// Set Infinity mode
|
|
//
|
|
|
|
if (abstr & _MCW_IC) {
|
|
cw |= IIC_AFFINE;
|
|
}
|
|
|
|
return cw;
|
|
}
|
|
|
|
|
|
|
|
/***
|
|
* _abstract_sw() - abstract fp status word
|
|
*
|
|
*Purpose:
|
|
* produce an abstract (machine independent) fp status word
|
|
*
|
|
*
|
|
*Entry:
|
|
* sw: machine status word
|
|
*
|
|
*Exit:
|
|
*
|
|
*Exceptions:
|
|
*
|
|
*******************************************************************************/
|
|
|
|
unsigned int _abstract_sw(unsigned short sw)
|
|
{
|
|
unsigned int abstr = 0;
|
|
|
|
|
|
if (sw & ISW_INVALID)
|
|
abstr |= _SW_INVALID;
|
|
if (sw & ISW_ZERODIVIDE)
|
|
abstr |= _SW_ZERODIVIDE;
|
|
if (sw & ISW_OVERFLOW)
|
|
abstr |= _SW_OVERFLOW;
|
|
if (sw & ISW_UNDERFLOW)
|
|
abstr |= _SW_UNDERFLOW;
|
|
if (sw & ISW_INEXACT)
|
|
abstr |= _SW_INEXACT;
|
|
if (sw & ISW_DENORMAL)
|
|
abstr |= _SW_DENORMAL;
|
|
|
|
return abstr;
|
|
}
|