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freebsd-dev/sys/gnu/i386/fpemul/reg_ld_str.c
Peter Wemm e8aef1d3b5 Use suword16/fuword16 instead of susword/fusword - this has two different 
definitions so far.. 16 bit on x86 and appears to be 32 bit on sparc64.
Be explicit to avoid suprises.
2002-06-20 07:23:08 +00:00

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/*
* reg_ld_str.c
*
* All of the functions which transfer data between user memory and FPU_REGs.
*
*
* Copyright (C) 1992,1993,1994
* W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
* Australia. E-mail billm@vaxc.cc.monash.edu.au
* All rights reserved.
*
* This copyright notice covers the redistribution and use of the
* FPU emulator developed by W. Metzenthen. It covers only its use
* in the 386BSD, FreeBSD and NetBSD operating systems. Any other
* use is not permitted under this copyright.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must include information specifying
* that source code for the emulator is freely available and include
* either:
* a) an offer to provide the source code for a nominal distribution
* fee, or
* b) list at least two alternative methods whereby the source
* can be obtained, e.g. a publically accessible bulletin board
* and an anonymous ftp site from which the software can be
* downloaded.
* 3. All advertising materials specifically mentioning features or use of
* this emulator must acknowledge that it was developed by W. Metzenthen.
* 4. The name of W. Metzenthen may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* The purpose of this copyright, based upon the Berkeley copyright, is to
* ensure that the covered software remains freely available to everyone.
*
* The software (with necessary differences) is also available, but under
* the terms of the GNU copyleft, for the Linux operating system and for
* the djgpp ms-dos extender.
*
* W. Metzenthen June 1994.
*
*
* $FreeBSD$
*
*/
/*---------------------------------------------------------------------------+
| Note: |
| The file contains code which accesses user memory. |
| Emulator static data may change when user memory is accessed, due to |
| other processes using the emulator while swapping is in progress. |
+---------------------------------------------------------------------------*/
#include <sys/param.h>
#include <sys/proc.h>
#include <sys/systm.h>
#include <machine/pcb.h>
#include <gnu/i386/fpemul/fpu_emu.h>
#include <gnu/i386/fpemul/fpu_system.h>
#include <gnu/i386/fpemul/exception.h>
#include <gnu/i386/fpemul/reg_constant.h>
#include <gnu/i386/fpemul/control_w.h>
#include <gnu/i386/fpemul/status_w.h>
#define EXTENDED_Emax 0x3fff /* largest valid exponent */
#define EXTENDED_Ebias 0x3fff
#define EXTENDED_Emin (-0x3ffe) /* smallest valid exponent */
#define DOUBLE_Emax 1023 /* largest valid exponent */
#define DOUBLE_Ebias 1023
#define DOUBLE_Emin (-1022) /* smallest valid exponent */
#define SINGLE_Emax 127 /* largest valid exponent */
#define SINGLE_Ebias 127
#define SINGLE_Emin (-126) /* smallest valid exponent */
#define LOST_UP (EX_Precision | SW_C1)
#define LOST_DOWN EX_Precision
FPU_REG FPU_loaded_data;
/* Get a long double from user memory */
void
reg_load_extended(void)
{
long double *s = (long double *) FPU_data_address;
unsigned long sigl, sigh, exp;
REENTRANT_CHECK(OFF);
/* Use temporary variables here because FPU_loaded data is static and
* hence re-entrancy problems can arise */
sigl = fuword((unsigned long *) s);
sigh = fuword(1 + (unsigned long *) s);
exp = fuword16(4 + (unsigned short *) s);
REENTRANT_CHECK(ON);
FPU_loaded_data.sigl = sigl;
FPU_loaded_data.sigh = sigh;
FPU_loaded_data.exp = exp;
if (FPU_loaded_data.exp & 0x8000)
FPU_loaded_data.sign = SIGN_NEG;
else
FPU_loaded_data.sign = SIGN_POS;
if ((FPU_loaded_data.exp &= 0x7fff) == 0) {
if (!(FPU_loaded_data.sigl | FPU_loaded_data.sigh)) {
FPU_loaded_data.tag = TW_Zero;
return;
}
/* The number is a de-normal or pseudodenormal. */
/* The 80486 doesn't regard pseudodenormals as denormals here. */
if (!(FPU_loaded_data.sigh & 0x80000000))
EXCEPTION(EX_Denormal);
FPU_loaded_data.exp++;
/* The default behaviour will now take care of it. */
} else
if (FPU_loaded_data.exp == 0x7fff) {
FPU_loaded_data.exp = EXTENDED_Emax;
if ((FPU_loaded_data.sigh == 0x80000000)
&& (FPU_loaded_data.sigl == 0)) {
FPU_loaded_data.tag = TW_Infinity;
return;
} else
if (!(FPU_loaded_data.sigh & 0x80000000)) {
/* Unsupported NaN data type */
EXCEPTION(EX_Invalid);
FPU_loaded_data.tag = TW_NaN;
return;
}
FPU_loaded_data.tag = TW_NaN;
return;
}
FPU_loaded_data.exp = (FPU_loaded_data.exp & 0x7fff) - EXTENDED_Ebias
+ EXP_BIAS;
FPU_loaded_data.tag = TW_Valid;
if (!(sigh & 0x80000000)) {
/* Unsupported data type */
EXCEPTION(EX_Invalid);
normalize_nuo(&FPU_loaded_data);
}
}
/* Get a double from user memory */
void
reg_load_double(void)
{
double *dfloat = (double *) FPU_data_address;
int exp;
unsigned m64, l64;
REENTRANT_CHECK(OFF);
m64 = fuword(1 + (unsigned long *) dfloat);
l64 = fuword((unsigned long *) dfloat);
REENTRANT_CHECK(ON);
if (m64 & 0x80000000)
FPU_loaded_data.sign = SIGN_NEG;
else
FPU_loaded_data.sign = SIGN_POS;
exp = ((m64 & 0x7ff00000) >> 20) - DOUBLE_Ebias;
m64 &= 0xfffff;
if (exp > DOUBLE_Emax) {
/* Infinity or NaN */
if ((m64 == 0) && (l64 == 0)) {
/* +- infinity */
FPU_loaded_data.exp = EXTENDED_Emax;
FPU_loaded_data.tag = TW_Infinity;
return;
} else {
/* Must be a signaling or quiet NaN */
FPU_loaded_data.exp = EXTENDED_Emax;
FPU_loaded_data.tag = TW_NaN;
FPU_loaded_data.sigh = (m64 << 11) | 0x80000000;
FPU_loaded_data.sigh |= l64 >> 21;
FPU_loaded_data.sigl = l64 << 11;
return;
}
} else
if (exp < DOUBLE_Emin) {
/* Zero or de-normal */
if ((m64 == 0) && (l64 == 0)) {
/* Zero */
int c = FPU_loaded_data.sign;
reg_move(&CONST_Z, &FPU_loaded_data);
FPU_loaded_data.sign = c;
return;
} else {
/* De-normal */
EXCEPTION(EX_Denormal);
FPU_loaded_data.exp = DOUBLE_Emin + EXP_BIAS;
FPU_loaded_data.tag = TW_Valid;
FPU_loaded_data.sigh = m64 << 11;
FPU_loaded_data.sigh |= l64 >> 21;
FPU_loaded_data.sigl = l64 << 11;
normalize_nuo(&FPU_loaded_data);
return;
}
} else {
FPU_loaded_data.exp = exp + EXP_BIAS;
FPU_loaded_data.tag = TW_Valid;
FPU_loaded_data.sigh = (m64 << 11) | 0x80000000;
FPU_loaded_data.sigh |= l64 >> 21;
FPU_loaded_data.sigl = l64 << 11;
return;
}
}
/* Get a float from user memory */
void
reg_load_single(void)
{
float *single = (float *) FPU_data_address;
unsigned m32;
int exp;
REENTRANT_CHECK(OFF);
m32 = fuword((unsigned long *) single);
REENTRANT_CHECK(ON);
if (m32 & 0x80000000)
FPU_loaded_data.sign = SIGN_NEG;
else
FPU_loaded_data.sign = SIGN_POS;
if (!(m32 & 0x7fffffff)) {
/* Zero */
int c = FPU_loaded_data.sign;
reg_move(&CONST_Z, &FPU_loaded_data);
FPU_loaded_data.sign = c;
return;
}
exp = ((m32 & 0x7f800000) >> 23) - SINGLE_Ebias;
m32 = (m32 & 0x7fffff) << 8;
if (exp < SINGLE_Emin) {
/* De-normals */
EXCEPTION(EX_Denormal);
FPU_loaded_data.exp = SINGLE_Emin + EXP_BIAS;
FPU_loaded_data.tag = TW_Valid;
FPU_loaded_data.sigh = m32;
FPU_loaded_data.sigl = 0;
normalize_nuo(&FPU_loaded_data);
return;
} else
if (exp > SINGLE_Emax) {
/* Infinity or NaN */
if (m32 == 0) {
/* +- infinity */
FPU_loaded_data.exp = EXTENDED_Emax;
FPU_loaded_data.tag = TW_Infinity;
return;
} else {
/* Must be a signaling or quiet NaN */
FPU_loaded_data.exp = EXTENDED_Emax;
FPU_loaded_data.tag = TW_NaN;
FPU_loaded_data.sigh = m32 | 0x80000000;
FPU_loaded_data.sigl = 0;
return;
}
} else {
FPU_loaded_data.exp = exp + EXP_BIAS;
FPU_loaded_data.sigh = m32 | 0x80000000;
FPU_loaded_data.sigl = 0;
FPU_loaded_data.tag = TW_Valid;
}
}
/* Get a long long from user memory */
void
reg_load_int64(void)
{
long long *_s = (long long *) FPU_data_address;
int e;
long long s;
REENTRANT_CHECK(OFF);
((unsigned long *) &s)[0] = fuword((unsigned long *) _s);
((unsigned long *) &s)[1] = fuword(1 + (unsigned long *) _s);
REENTRANT_CHECK(ON);
if (s == 0) {
reg_move(&CONST_Z, &FPU_loaded_data);
return;
}
if (s > 0)
FPU_loaded_data.sign = SIGN_POS;
else {
s = -s;
FPU_loaded_data.sign = SIGN_NEG;
}
e = EXP_BIAS + 63;
*((long long *) &FPU_loaded_data.sigl) = s;
FPU_loaded_data.exp = e;
FPU_loaded_data.tag = TW_Valid;
normalize_nuo(&FPU_loaded_data);
}
/* Get a long from user memory */
void
reg_load_int32(void)
{
long *_s = (long *) FPU_data_address;
long s;
int e;
REENTRANT_CHECK(OFF);
s = (long) fuword((unsigned long *) _s);
REENTRANT_CHECK(ON);
if (s == 0) {
reg_move(&CONST_Z, &FPU_loaded_data);
return;
}
if (s > 0)
FPU_loaded_data.sign = SIGN_POS;
else {
s = -s;
FPU_loaded_data.sign = SIGN_NEG;
}
e = EXP_BIAS + 31;
FPU_loaded_data.sigh = s;
FPU_loaded_data.sigl = 0;
FPU_loaded_data.exp = e;
FPU_loaded_data.tag = TW_Valid;
normalize_nuo(&FPU_loaded_data);
}
/* Get a short from user memory */
void
reg_load_int16(void)
{
short *_s = (short *) FPU_data_address;
int s, e;
REENTRANT_CHECK(OFF);
/* Cast as short to get the sign extended. */
s = (short) fuword16((unsigned short *) _s);
REENTRANT_CHECK(ON);
if (s == 0) {
reg_move(&CONST_Z, &FPU_loaded_data);
return;
}
if (s > 0)
FPU_loaded_data.sign = SIGN_POS;
else {
s = -s;
FPU_loaded_data.sign = SIGN_NEG;
}
e = EXP_BIAS + 15;
FPU_loaded_data.sigh = s << 16;
FPU_loaded_data.sigl = 0;
FPU_loaded_data.exp = e;
FPU_loaded_data.tag = TW_Valid;
normalize_nuo(&FPU_loaded_data);
}
/* Get a packed bcd array from user memory */
void
reg_load_bcd(void)
{
char *s = (char *) FPU_data_address;
int pos;
unsigned char bcd;
long long l = 0;
for (pos = 8; pos >= 0; pos--) {
l *= 10;
REENTRANT_CHECK(OFF);
bcd = (unsigned char) fubyte((unsigned char *) s + pos);
REENTRANT_CHECK(ON);
l += bcd >> 4;
l *= 10;
l += bcd & 0x0f;
}
/* Finish all access to user memory before putting stuff into the
* static FPU_loaded_data */
REENTRANT_CHECK(OFF);
FPU_loaded_data.sign =
((unsigned char) fubyte((unsigned char *) s + 9)) & 0x80 ?
SIGN_NEG : SIGN_POS;
REENTRANT_CHECK(ON);
if (l == 0) {
char sign = FPU_loaded_data.sign;
reg_move(&CONST_Z, &FPU_loaded_data);
FPU_loaded_data.sign = sign;
} else {
*((long long *) &FPU_loaded_data.sigl) = l;
FPU_loaded_data.exp = EXP_BIAS + 63;
FPU_loaded_data.tag = TW_Valid;
normalize_nuo(&FPU_loaded_data);
}
}
/*===========================================================================*/
/* Put a long double into user memory */
int
reg_store_extended(void)
{
long double *d = (long double *) FPU_data_address;
long e = FPU_st0_ptr->exp - EXP_BIAS + EXTENDED_Ebias;
unsigned short sign = FPU_st0_ptr->sign * 0x8000;
unsigned long ls, ms;
if (FPU_st0_tag == TW_Valid) {
if (e >= 0x7fff) {
EXCEPTION(EX_Overflow); /* Overflow */
/* This is a special case: see sec 16.2.5.1 of the
* 80486 book */
if (control_word & EX_Overflow) {
/* Overflow to infinity */
ls = 0;
ms = 0x80000000;
e = 0x7fff;
} else
return 0;
} else
if (e <= 0) {
if (e > -63) {
/* Correctly format the de-normal */
int precision_loss;
FPU_REG tmp;
EXCEPTION(EX_Denormal);
reg_move(FPU_st0_ptr, &tmp);
tmp.exp += -EXTENDED_Emin + 63; /* largest exp to be 62 */
if ((precision_loss = round_to_int(&tmp))) {
EXCEPTION(EX_Underflow | precision_loss);
/* This is a special case: see
* sec 16.2.5.1 of the 80486
* book */
if (!(control_word & EX_Underflow))
return 0;
}
e = 0;
ls = tmp.sigl;
ms = tmp.sigh;
} else {
/* ****** ??? This should not be
* possible */
EXCEPTION(EX_Underflow); /* Underflow */
/* This is a special case: see sec
* 16.2.5.1 of the 80486 book */
if (control_word & EX_Underflow) {
/* Underflow to zero */
ls = 0;
ms = 0;
e = FPU_st0_ptr->sign == SIGN_POS ? 0x7fff : 0xffff;
} else
return 0;
}
} else {
ls = FPU_st0_ptr->sigl;
ms = FPU_st0_ptr->sigh;
}
} else
if (FPU_st0_tag == TW_Zero) {
ls = ms = 0;
e = 0;
} else
if (FPU_st0_tag == TW_Infinity) {
ls = 0;
ms = 0x80000000;
e = 0x7fff;
} else
if (FPU_st0_tag == TW_NaN) {
ls = FPU_st0_ptr->sigl;
ms = FPU_st0_ptr->sigh;
e = 0x7fff;
} else
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack
* underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN
* indefinite */
ls = 0;
ms = 0xc0000000;
e = 0xffff;
} else
return 0;
} else {
/* We don't use TW_Denormal
* yet ... perhaps never! */
EXCEPTION(EX_Invalid);
/* Store a NaN */
e = 0x7fff;
ls = 1;
ms = 0x80000000;
}
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 10); */
suword((unsigned long *) d, ls);
suword(1 + (unsigned long *) d, ms);
suword16(4 + (short *) d, (unsigned short) e | sign);
REENTRANT_CHECK(ON);
return 1;
}
/* Put a double into user memory */
int
reg_store_double(void)
{
double *dfloat = (double *) FPU_data_address;
unsigned long l[2];
if (FPU_st0_tag == TW_Valid) {
int exp;
FPU_REG tmp;
reg_move(FPU_st0_ptr, &tmp);
exp = tmp.exp - EXP_BIAS;
if (exp < DOUBLE_Emin) { /* It may be a denormal */
/* Make a de-normal */
int precision_loss;
if (exp <= -EXTENDED_Ebias)
EXCEPTION(EX_Denormal);
tmp.exp += -DOUBLE_Emin + 52; /* largest exp to be 51 */
if ((precision_loss = round_to_int(&tmp))) {
#ifdef PECULIAR_486
/* Did it round to a non-denormal ? */
/* This behaviour might be regarded as
* peculiar, it appears that the 80486 rounds
* to the dest precision, then converts to
* decide underflow. */
if ((tmp.sigh == 0x00100000) && (tmp.sigl == 0) &&
(FPU_st0_ptr->sigl & 0x000007ff))
EXCEPTION(precision_loss);
else
#endif /* PECULIAR_486 */
{
EXCEPTION(EX_Underflow | precision_loss);
/* This is a special case: see sec
* 16.2.5.1 of the 80486 book */
if (!(control_word & EX_Underflow))
return 0;
}
}
l[0] = tmp.sigl;
l[1] = tmp.sigh;
} else {
if (tmp.sigl & 0x000007ff) {
unsigned long increment = 0; /* avoid gcc warnings */
switch (control_word & CW_RC) {
case RC_RND:
/* Rounding can get a little messy.. */
increment = ((tmp.sigl & 0x7ff) > 0x400) | /* nearest */
((tmp.sigl & 0xc00) == 0xc00); /* odd -> even */
break;
case RC_DOWN: /* towards -infinity */
increment = (tmp.sign == SIGN_POS) ? 0 : tmp.sigl & 0x7ff;
break;
case RC_UP: /* towards +infinity */
increment = (tmp.sign == SIGN_POS) ? tmp.sigl & 0x7ff : 0;
break;
case RC_CHOP:
increment = 0;
break;
}
/* Truncate the mantissa */
tmp.sigl &= 0xfffff800;
if (increment) {
set_precision_flag_up();
if (tmp.sigl >= 0xfffff800) {
/* the sigl part overflows */
if (tmp.sigh == 0xffffffff) {
/* The sigh part
* overflows */
tmp.sigh = 0x80000000;
exp++;
if (exp >= EXP_OVER)
goto overflow;
} else {
tmp.sigh++;
}
tmp.sigl = 0x00000000;
} else {
/* We only need to increment
* sigl */
tmp.sigl += 0x00000800;
}
} else
set_precision_flag_down();
}
l[0] = (tmp.sigl >> 11) | (tmp.sigh << 21);
l[1] = ((tmp.sigh >> 11) & 0xfffff);
if (exp > DOUBLE_Emax) {
overflow:
EXCEPTION(EX_Overflow);
/* This is a special case: see sec 16.2.5.1 of
* the 80486 book */
if (control_word & EX_Overflow) {
/* Overflow to infinity */
l[0] = 0x00000000; /* Set to */
l[1] = 0x7ff00000; /* + INF */
} else
return 0;
} else {
/* Add the exponent */
l[1] |= (((exp + DOUBLE_Ebias) & 0x7ff) << 20);
}
}
} else
if (FPU_st0_tag == TW_Zero) {
/* Number is zero */
l[0] = 0;
l[1] = 0;
} else
if (FPU_st0_tag == TW_Infinity) {
l[0] = 0;
l[1] = 0x7ff00000;
} else
if (FPU_st0_tag == TW_NaN) {
/* See if we can get a valid NaN from
* the FPU_REG */
l[0] = (FPU_st0_ptr->sigl >> 11) | (FPU_st0_ptr->sigh << 21);
l[1] = ((FPU_st0_ptr->sigh >> 11) & 0xfffff);
if (!(l[0] | l[1])) {
/* This case does not seem to
* be handled by the 80486
* specs */
EXCEPTION(EX_Invalid);
/* Make the quiet NaN "real
* indefinite" */
goto put_indefinite;
}
l[1] |= 0x7ff00000;
} else
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack
* underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN
* indefinite */
put_indefinite:
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_W
* RITE, (void *)
* dfloat, 8); */
suword((unsigned long *) dfloat, 0);
suword(1 + (unsigned long *) dfloat, 0xfff80000);
REENTRANT_CHECK(ON);
return 1;
} else
return 0;
}
#if 0 /* TW_Denormal is not used yet, and probably
* won't be */
else
if (FPU_st0_tag == TW_Denormal) {
/* Extended real ->
* double real will
* always underflow */
l[0] = l[1] = 0;
EXCEPTION(EX_Underflow);
}
#endif
if (FPU_st0_ptr->sign)
l[1] |= 0x80000000;
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, (void *) dfloat, 8);*/
suword((u_long *) dfloat, l[0]);
suword((u_long *) dfloat + 1, l[1]);
/*
suword(l[0], (unsigned long *) dfloat);
suword(l[1], 1 + (unsigned long *) dfloat);*/
REENTRANT_CHECK(ON);
return 1;
}
/* Put a float into user memory */
int
reg_store_single(void)
{
float *single = (float *) FPU_data_address;
long templ = 0;
if (FPU_st0_tag == TW_Valid) {
int exp;
FPU_REG tmp;
reg_move(FPU_st0_ptr, &tmp);
exp = tmp.exp - EXP_BIAS;
if (exp < SINGLE_Emin) {
/* Make a de-normal */
int precision_loss;
if (exp <= -EXTENDED_Ebias)
EXCEPTION(EX_Denormal);
tmp.exp += -SINGLE_Emin + 23; /* largest exp to be 22 */
if ((precision_loss = round_to_int(&tmp))) {
#ifdef PECULIAR_486
/* Did it round to a non-denormal ? */
/* This behaviour might be regarded as
* peculiar, it appears that the 80486 rounds
* to the dest precision, then converts to
* decide underflow. */
if ((tmp.sigl == 0x00800000) &&
((FPU_st0_ptr->sigh & 0x000000ff) || FPU_st0_ptr->sigl))
EXCEPTION(precision_loss);
else
#endif /* PECULIAR_486 */
{
EXCEPTION(EX_Underflow | precision_loss);
/* This is a special case: see sec
* 16.2.5.1 of the 80486 book */
if (!(control_word & EX_Underflow))
return 0;
}
}
templ = tmp.sigl;
} else {
if (tmp.sigl | (tmp.sigh & 0x000000ff)) {
unsigned long increment = 0; /* avoid gcc warnings */
unsigned long sigh = tmp.sigh;
unsigned long sigl = tmp.sigl;
switch (control_word & CW_RC) {
case RC_RND:
increment = ((sigh & 0xff) > 0x80) /* more than half */
||(((sigh & 0xff) == 0x80) && sigl) /* more than half */
||((sigh & 0x180) == 0x180); /* round to even */
break;
case RC_DOWN: /* towards -infinity */
increment = (tmp.sign == SIGN_POS)
? 0 : (sigl | (sigh & 0xff));
break;
case RC_UP: /* towards +infinity */
increment = (tmp.sign == SIGN_POS)
? (sigl | (sigh & 0xff)) : 0;
break;
case RC_CHOP:
increment = 0;
break;
}
/* Truncate part of the mantissa */
tmp.sigl = 0;
if (increment) {
set_precision_flag_up();
if (sigh >= 0xffffff00) {
/* The sigh part overflows */
tmp.sigh = 0x80000000;
exp++;
if (exp >= EXP_OVER)
goto overflow;
} else {
tmp.sigh &= 0xffffff00;
tmp.sigh += 0x100;
}
} else {
set_precision_flag_down();
tmp.sigh &= 0xffffff00; /* Finish the truncation */
}
}
templ = (tmp.sigh >> 8) & 0x007fffff;
if (exp > SINGLE_Emax) {
overflow:
EXCEPTION(EX_Overflow);
/* This is a special case: see sec 16.2.5.1 of
* the 80486 book */
if (control_word & EX_Overflow) {
/* Overflow to infinity */
templ = 0x7f800000;
} else
return 0;
} else
templ |= ((exp + SINGLE_Ebias) & 0xff) << 23;
}
} else
if (FPU_st0_tag == TW_Zero) {
templ = 0;
} else
if (FPU_st0_tag == TW_Infinity) {
templ = 0x7f800000;
} else
if (FPU_st0_tag == TW_NaN) {
/* See if we can get a valid NaN from
* the FPU_REG */
templ = FPU_st0_ptr->sigh >> 8;
if (!(templ & 0x3fffff)) {
/* This case does not seem to
* be handled by the 80486
* specs */
EXCEPTION(EX_Invalid);
/* Make the quiet NaN "real
* indefinite" */
goto put_indefinite;
}
templ |= 0x7f800000;
} else
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack
* underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN
* indefinite */
put_indefinite:
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, (void *) single, 4); */
suword((unsigned long *) single, 0xffc00000);
REENTRANT_CHECK(ON);
return 1;
} else
return 0;
}
#if 0 /* TW_Denormal is not used yet, and probably
* won't be */
else
if (FPU_st0_tag == TW_Denormal) {
/* Extended real ->
* real will always
* underflow */
templ = 0;
EXCEPTION(EX_Underflow);
}
#endif
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x106);
return 0;
}
#endif
if (FPU_st0_ptr->sign)
templ |= 0x80000000;
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, (void *) single, 4); */
suword((unsigned long *) single, templ);
REENTRANT_CHECK(ON);
return 1;
}
/* Put a long long into user memory */
int
reg_store_int64(void)
{
long long *d = (long long *) FPU_data_address;
FPU_REG t;
long long tll;
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
goto put_indefinite;
} else
return 0;
}
reg_move(FPU_st0_ptr, &t);
round_to_int(&t);
((long *) &tll)[0] = t.sigl;
((long *) &tll)[1] = t.sigh;
if ((t.sigh & 0x80000000) &&
!((t.sigh == 0x80000000) && (t.sigl == 0) && (t.sign == SIGN_NEG))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
if (control_word & EX_Invalid) {
/* Produce "indefinite" */
put_indefinite:
((long *) &tll)[1] = 0x80000000;
((long *) &tll)[0] = 0;
} else
return 0;
} else
if (t.sign)
tll = -tll;
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, (void *) d, 8); */
suword((unsigned long *) d, ((long *) &tll)[0]);
suword(1 + (unsigned long *) d, ((long *) &tll)[1]);
REENTRANT_CHECK(ON);
return 1;
}
/* Put a long into user memory */
int
reg_store_int32(void)
{
long *d = (long *) FPU_data_address;
FPU_REG t;
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 4);*/
suword((unsigned long *) d, 0x80000000);
REENTRANT_CHECK(ON);
return 1;
} else
return 0;
}
reg_move(FPU_st0_ptr, &t);
round_to_int(&t);
if (t.sigh ||
((t.sigl & 0x80000000) &&
!((t.sigl == 0x80000000) && (t.sign == SIGN_NEG)))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
if (control_word & EX_Invalid) {
/* Produce "indefinite" */
t.sigl = 0x80000000;
} else
return 0;
} else
if (t.sign)
t.sigl = -(long) t.sigl;
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 4); */
suword((unsigned long *) d, t.sigl);
REENTRANT_CHECK(ON);
return 1;
}
/* Put a short into user memory */
int
reg_store_int16(void)
{
short *d = (short *) FPU_data_address;
FPU_REG t;
short ts;
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 2);*/
suword16((unsigned short *) d, 0x8000);
REENTRANT_CHECK(ON);
return 1;
} else
return 0;
}
reg_move(FPU_st0_ptr, &t);
round_to_int(&t);
if (t.sigh ||
((t.sigl & 0xffff8000) &&
!((t.sigl == 0x8000) && (t.sign == SIGN_NEG)))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
if (control_word & EX_Invalid) {
/* Produce "indefinite" */
ts = 0x8000;
} else
return 0;
} else
if (t.sign)
t.sigl = -t.sigl;
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 2); */
suword16((short *) d, (short) t.sigl);
REENTRANT_CHECK(ON);
return 1;
}
/* Put a packed bcd array into user memory */
int
reg_store_bcd(void)
{
char *d = (char *) FPU_data_address;
FPU_REG t;
long long ll;
unsigned char b;
int i;
unsigned char sign = (FPU_st0_ptr->sign == SIGN_NEG) ? 0x80 : 0;
if (FPU_st0_tag == TW_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
goto put_indefinite;
} else
return 0;
}
reg_move(FPU_st0_ptr, &t);
round_to_int(&t);
ll = *(long long *) (&t.sigl);
/* Check for overflow, by comparing with 999999999999999999 decimal. */
if ((t.sigh > 0x0de0b6b3) ||
((t.sigh == 0x0de0b6b3) && (t.sigl > 0xa763ffff))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
if (control_word & EX_Invalid) {
put_indefinite:
/* Produce "indefinite" */
REENTRANT_CHECK(OFF);
/* verify_area(VERIFY_WRITE, d, 10);*/
subyte((unsigned char *) d + 7, 0xff);
subyte((unsigned char *) d + 8, 0xff);
subyte((unsigned char *) d + 9, 0xff);
REENTRANT_CHECK(ON);
return 1;
} else
return 0;
}
/* verify_area(VERIFY_WRITE, d, 10);*/
for (i = 0; i < 9; i++) {
b = div_small(&ll, 10);
b |= (div_small(&ll, 10)) << 4;
REENTRANT_CHECK(OFF);
subyte((unsigned char *) d + i, b);
REENTRANT_CHECK(ON);
}
REENTRANT_CHECK(OFF);
subyte((unsigned char *) d + 9, sign);
REENTRANT_CHECK(ON);
return 1;
}
/*===========================================================================*/
/* r gets mangled such that sig is int, sign:
it is NOT normalized */
/* The return value (in eax) is zero if the result is exact,
if bits are changed due to rounding, truncation, etc, then
a non-zero value is returned */
/* Overflow is signalled by a non-zero return value (in eax).
In the case of overflow, the returned significand always has the
the largest possible value */
/* The value returned in eax is never actually needed :-) */
int
round_to_int(FPU_REG * r)
{
char very_big;
unsigned eax;
if (r->tag == TW_Zero) {
/* Make sure that zero is returned */
*(long long *) &r->sigl = 0;
return 0; /* o.k. */
}
if (r->exp > EXP_BIAS + 63) {
r->sigl = r->sigh = ~0; /* The largest representable number */
return 1; /* overflow */
}
eax = shrxs(&r->sigl, EXP_BIAS + 63 - r->exp);
very_big = !(~(r->sigh) | ~(r->sigl)); /* test for 0xfff...fff */
#define half_or_more (eax & 0x80000000)
#define frac_part (eax)
#define more_than_half ((eax & 0x80000001) == 0x80000001)
switch (control_word & CW_RC) {
case RC_RND:
if (more_than_half /* nearest */
|| (half_or_more && (r->sigl & 1))) { /* odd -> even */
if (very_big)
return 1; /* overflow */
(*(long long *) (&r->sigl))++;
return LOST_UP;
}
break;
case RC_DOWN:
if (frac_part && r->sign) {
if (very_big)
return 1; /* overflow */
(*(long long *) (&r->sigl))++;
return LOST_UP;
}
break;
case RC_UP:
if (frac_part && !r->sign) {
if (very_big)
return 1; /* overflow */
(*(long long *) (&r->sigl))++;
return LOST_UP;
}
break;
case RC_CHOP:
break;
}
return eax ? LOST_DOWN : 0;
}
/*===========================================================================*/
char *
fldenv(void)
{
char *s = (char *) FPU_data_address;
unsigned short tag_word = 0;
unsigned char tag;
int i;
REENTRANT_CHECK(OFF);
control_word = fuword16((unsigned short *) s);
status_word = fuword16((unsigned short *) (s + 4));
tag_word = fuword16((unsigned short *) (s + 8));
ip_offset = fuword((unsigned long *) (s + 0x0c));
cs_selector = fuword((unsigned long *) (s + 0x10));
data_operand_offset = fuword((unsigned long *) (s + 0x14));
operand_selector = fuword((unsigned long *) (s + 0x18));
REENTRANT_CHECK(ON);
top = (status_word >> SW_Top_Shift) & 7;
for (i = 0; i < 8; i++) {
tag = tag_word & 3;
tag_word >>= 2;
switch (tag) {
case 0:
regs[i].tag = TW_Valid;
break;
case 1:
regs[i].tag = TW_Zero;
break;
case 2:
regs[i].tag = TW_NaN;
break;
case 3:
regs[i].tag = TW_Empty;
break;
}
}
/* We want no net effect: */
FPU_data_address = (void *) (intptr_t) data_operand_offset;
FPU_entry_eip = ip_offset; /* We want no net effect */
return s + 0x1c;
}
void
frstor(void)
{
int i, stnr;
unsigned char tag;
unsigned short saved_status, saved_control;
char *s = (char *) fldenv();
saved_status = status_word;
saved_control = control_word;
control_word = 0x037f; /* Mask all interrupts while we load. */
for (i = 0; i < 8; i++) {
/* load each register */
FPU_data_address = (void *) (s + i * 10);
reg_load_extended();
stnr = (i + top) & 7;
tag = regs[stnr].tag; /* derived from the loaded tag word */
reg_move(&FPU_loaded_data, &regs[stnr]);
if (tag == TW_NaN) {
/* The current data is a special, i.e. NaN,
* unsupported, infinity, or denormal */
unsigned char t = regs[stnr].tag; /* derived from the new
* data */
if ( /* (t == TW_Valid) || *** */ (t == TW_Zero))
regs[stnr].tag = TW_NaN;
} else
regs[stnr].tag = tag;
}
control_word = saved_control;
status_word = saved_status;
/* We want no net effect: */
FPU_data_address = (void *) (intptr_t) data_operand_offset;
}
unsigned short
tag_word(void)
{
unsigned short word = 0;
unsigned char tag;
int i;
for (i = 7; i >= 0; i--) {
switch (tag = regs[i].tag) {
#if 0 /* TW_Denormal is not used yet, and probably
* won't be */
case TW_Denormal:
#endif
case TW_Valid:
if (regs[i].exp <= (EXP_BIAS - EXTENDED_Ebias))
tag = 2;
break;
case TW_Infinity:
case TW_NaN:
tag = 2;
break;
case TW_Empty:
tag = 3;
break;
/* TW_Valid and TW_Zero already have the correct value */
}
word <<= 2;
word |= tag;
}
return word;
}
char *
fstenv(void)
{
char *d = (char *) FPU_data_address;
/* verify_area(VERIFY_WRITE, d, 28);*/
#if 0 /****/
*(unsigned short *) &cs_selector = fpu_cs;
*(unsigned short *) &operand_selector = fpu_os;
#endif /****/
REENTRANT_CHECK(OFF);
suword16((unsigned short *) d, control_word);
suword16((unsigned short *) (d + 4), (status_word & ~SW_Top) | ((top & 7) << SW_Top_Shift));
suword16((unsigned short *) (d + 8), tag_word());
suword((unsigned long *) (d + 0x0c), ip_offset);
suword((unsigned long *) (d + 0x10), cs_selector);
suword((unsigned long *) (d + 0x14), data_operand_offset);
suword((unsigned long *) (d + 0x18), operand_selector);
REENTRANT_CHECK(ON);
return d + 0x1c;
}
void
fsave(void)
{
char *d;
FPU_REG tmp, *rp;
int i;
short e;
d = fstenv();
/* verify_area(VERIFY_WRITE, d, 80);*/
for (i = 0; i < 8; i++) {
/* Store each register in the order: st(0), st(1), ... */
rp = &regs[(top + i) & 7];
e = rp->exp - EXP_BIAS + EXTENDED_Ebias;
if (rp->tag == TW_Valid) {
if (e >= 0x7fff) {
/* Overflow to infinity */
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), 0);
suword((unsigned long *) (d + i * 10 + 4), 0);
REENTRANT_CHECK(ON);
e = 0x7fff;
} else
if (e <= 0) {
if (e > -63) {
/* Make a de-normal */
reg_move(rp, &tmp);
tmp.exp += -EXTENDED_Emin + 63; /* largest exp to be 62 */
round_to_int(&tmp);
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), tmp.sigl);
suword((unsigned long *) (d + i * 10 + 4), tmp.sigh);
REENTRANT_CHECK(ON);
} else {
/* Underflow to zero */
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), 0);
suword((unsigned long *) (d + i * 10 + 4), 0);
REENTRANT_CHECK(ON);
}
e = 0;
} else {
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), rp->sigl);
suword((unsigned long *) (d + i * 10 + 4), rp->sigh);
REENTRANT_CHECK(ON);
}
} else
if (rp->tag == TW_Zero) {
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), 0);
suword((unsigned long *) (d + i * 10 + 4), 0);
REENTRANT_CHECK(ON);
e = 0;
} else
if (rp->tag == TW_Infinity) {
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), 0);
suword((unsigned long *) (d + i * 10 + 4), 0x80000000);
REENTRANT_CHECK(ON);
e = 0x7fff;
} else
if (rp->tag == TW_NaN) {
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), rp->sigl);
suword((unsigned long *) (d + i * 10 + 4), rp->sigh);
REENTRANT_CHECK(ON);
e = 0x7fff;
} else
if (rp->tag == TW_Empty) {
/* just copy the reg */
REENTRANT_CHECK(OFF);
suword((unsigned long *) (d + i * 10), rp->sigl);
suword((unsigned long *) (d + i * 10 + 4), rp->sigh);
REENTRANT_CHECK(ON);
}
e |= rp->sign == SIGN_POS ? 0 : 0x8000;
REENTRANT_CHECK(OFF);
suword16((unsigned short *) (d + i * 10 + 8), e);
REENTRANT_CHECK(ON);
}
finit();
}
/*===========================================================================*/
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