OpenSolaris_b135/lib/libbc/libc/gen/common/_unpack_dble.c
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 1988 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include "base_conversion.h"
/* Normalize a number. Does not affect zeros, infs, or NaNs. */
void
_fp_normalize(unpacked *pu)
{
int i;
short unsigned nlzwords, nlzbits;
long unsigned t;
if ((*pu).fpclass == fp_normal) {
for (nlzwords = 0; (pu->significand[nlzwords] == 0) && (nlzwords < UNPACKED_SIZE); nlzwords++);
if (nlzwords >= UNPACKED_SIZE) {
(*pu).fpclass = fp_zero;
return;
}
if (nlzwords > 0) {
for (i = 0; i < UNPACKED_SIZE - nlzwords; i++)
pu->significand[i] = pu->significand[i + nlzwords];
for (; i < UNPACKED_SIZE; i++)
pu->significand[i] = 0;
pu->exponent -= 32 * nlzwords;
}
for (; pu->significand[UNPACKED_SIZE - 1 - nlzwords] == 0; nlzwords++);
/* nlzwords is now the count of trailing zero words. */
nlzbits = 0;
t = pu->significand[0];
/* TESTS to determine normalize count. */
#define SHIFTMACRO(n) if (t <= (((unsigned long) 0xffffffff) >> n)) { t = t<<n ; nlzbits += n ; }
SHIFTMACRO(16);
SHIFTMACRO(8);
SHIFTMACRO(4);
SHIFTMACRO(2);
SHIFTMACRO(1);
pu->exponent -= nlzbits;
if (nlzbits >= 1) { /* small shift */
unsigned long high, low, shiftout = 0;
for (i = UNPACKED_SIZE - 1 - nlzwords; i >= 0; i--) {
high = pu->significand[i] << nlzbits;
low = pu->significand[i] >> (32 - nlzbits);
pu->significand[i] = shiftout | high;
shiftout = low;
}
}
}
}
/* Set the exception bit in the current exception register. */
void
_fp_set_exception(enum fp_exception_type ex)
{
_fp_current_exceptions |= 1 << (int) ex;
}
enum fp_class_type
_class_double(double *x)
{
double_equivalence kluge;
kluge.x = *x;
if (kluge.f.msw.exponent == 0) { /* 0 or sub */
if ((kluge.f.msw.significand == 0) && (kluge.f.significand2 == 0))
return fp_zero;
else
return fp_subnormal;
} else if (kluge.f.msw.exponent == 0x7ff) { /* inf or nan */
if ((kluge.f.msw.significand == 0) && (kluge.f.significand2 == 0))
return fp_infinity;
else if (kluge.f.msw.significand >= 0x40000)
return fp_quiet;
else
return fp_signaling;
} else
return fp_normal;
}
/* Left shift significand by 11 <= n <= 16 bits. Affect all classes. */
void
_fp_leftshift(unpacked *pu, unsigned n)
{
int i;
unsigned long high, low, shiftout = 0;
for (i = UNPACKED_SIZE - 1; i >= 0; i--) {
high = pu->significand[i] << n;
low = pu->significand[i] >> (32 - n);
pu->significand[i] = shiftout | high;
shiftout = low;
}
}
void
_unpack_double(unpacked *pu, double *px)
{
double_equivalence x;
int i;
x.x = *px;
(*pu).sign = x.f.msw.sign;
pu->significand[1] = x.f.significand2;
for (i = 2; i < UNPACKED_SIZE; i++)
pu->significand[i] = 0;
if (x.f.msw.exponent == 0) { /* zero or sub */
if ((x.f.msw.significand == 0) && (x.f.significand2 == 0)) { /* zero */
pu->fpclass = fp_zero;
return;
} else { /* subnormal */
pu->fpclass = fp_normal;
pu->exponent = 12 - DOUBLE_BIAS;
pu->significand[0] = x.f.msw.significand;
_fp_normalize(pu);
return;
}
} else if (x.f.msw.exponent == 0x7ff) { /* inf or nan */
if ((x.f.msw.significand == 0) && (x.f.significand2 == 0)) { /* inf */
pu->fpclass = fp_infinity;
return;
} else { /* nan */
if ((x.f.msw.significand & 0x80000) != 0) { /* quiet */
pu->fpclass = fp_quiet;
} else {/* signaling */
pu->fpclass = fp_quiet;
_fp_set_exception(fp_invalid);
}
pu->significand[0] = 0x80000 | x.f.msw.significand;
_fp_leftshift(pu, 11);
return;
}
}
(*pu).exponent = x.f.msw.exponent - DOUBLE_BIAS;
(*pu).fpclass = fp_normal;
(*pu).significand[0] = 0x100000 | x.f.msw.significand;
_fp_leftshift(pu, 11);
}
enum fp_class_type
_class_quadruple(quadruple *x)
{
quadruple_equivalence kluge;
int i;
for (i = 0; i < 4; i++)
#ifdef __STDC__
kluge.x = *x;
#else
kluge.x.u[i] = x->u[i];
#endif
if (kluge.f.msw.exponent == 0) { /* 0 or sub */
if ((kluge.f.msw.significand == 0) && (kluge.f.significand2 == 0) && (kluge.f.significand3 == 0) && (kluge.f.significand4 == 0))
return fp_zero;
else
return fp_subnormal;
} else if (kluge.f.msw.exponent == 0x7fff) { /* inf or nan */
if ((kluge.f.msw.significand == 0) && (kluge.f.significand2 == 0) && (kluge.f.significand3 == 0) && (kluge.f.significand4 == 0))
return fp_infinity;
else if ((kluge.f.msw.significand & 0xffff) >= 0x8000)
return fp_quiet;
else
return fp_signaling;
} else
return fp_normal;
}
void
_unpack_quadruple(unpacked *pu, quadruple *px)
{
quadruple_equivalence x;
int i;
for (i = 0; i < 4; i++)
#ifdef __STDC__
x.x = *px;
#else
x.x.u[i] = px->u[i];
#endif
(*pu).sign = x.f.msw.sign;
pu->significand[1] = x.f.significand2;
pu->significand[2] = x.f.significand3;
pu->significand[3] = x.f.significand4;
for (i = 4; i < UNPACKED_SIZE; i++)
pu->significand[i] = 0;
if (x.f.msw.exponent == 0) { /* zero or sub */
if ((x.f.msw.significand | x.f.significand2 | x.f.significand3 | x.f.significand4) == 0) { /* zero */
pu->fpclass = fp_zero;
goto ret;
} else { /* subnormal */
pu->fpclass = fp_normal;
pu->exponent = 16 - QUAD_BIAS;
pu->significand[0] = x.f.msw.significand;
_fp_normalize(pu);
goto ret;
}
} else if (x.f.msw.exponent == 0x7fff) { /* inf or nan */
if ((x.f.msw.significand | x.f.significand2 | x.f.significand3 | x.f.significand4) == 0) { /* inf */
pu->fpclass = fp_infinity;
goto ret;
} else { /* nan */
if ((x.f.msw.significand & 0x8000) != 0) { /* quiet */
pu->fpclass = fp_quiet;
} else {/* signaling */
pu->fpclass = fp_quiet;
_fp_set_exception(fp_invalid);
}
pu->significand[0] = 0x8000 | x.f.msw.significand;
_fp_leftshift(pu, 16);
goto ret;
}
}
(*pu).exponent = x.f.msw.exponent - QUAD_BIAS;
(*pu).fpclass = fp_normal;
(*pu).significand[0] = 0x10000 | x.f.msw.significand;
_fp_leftshift(pu, 15);
ret:
/*
* printf("/n _unpack_quadruple ") ; _display_unpacked(pu);
*/
return;
}