newlib/winsup/mingw/mingwex/math/cephes_emath.c

1319 lines
20 KiB
C
Raw Normal View History

/* This file is extracted from S L Moshier's ioldoubl.c,
* modified for use in MinGW
*
* Extended precision arithmetic functions for long double I/O.
* This program has been placed in the public domain.
*/
/*
* Revision history:
*
* 5 Jan 84 PDP-11 assembly language version
* 6 Dec 86 C language version
* 30 Aug 88 100 digit version, improved rounding
* 15 May 92 80-bit long double support
*
* Author: S. L. Moshier.
*
* 6 Oct 02 Modified for MinGW by inlining utility routines,
* removing global variables and splitting out strtold
* from _IO_ldtoa and _IO_ldtostr.
*
* Danny Smith <dannysmith@users.sourceforge.net>
*
*/
#include "cephes_emath.h"
/*
* The constants are for 64 bit precision.
*/
/* Move in external format number,
* converting it to internal format.
*/
void __emovi(const short unsigned int * __restrict__ a,
short unsigned int * __restrict__ b)
{
register const unsigned short *p;
register unsigned short *q;
int i;
q = b;
p = a + (NE-1); /* point to last word of external number */
/* get the sign bit */
if( *p & 0x8000 )
*q++ = 0xffff;
else
*q++ = 0;
/* get the exponent */
*q = *p--;
*q++ &= 0x7fff; /* delete the sign bit */
#ifdef INFINITY
if( (*(q-1) & 0x7fff) == 0x7fff )
{
#ifdef NANS
if( __eisnan(a) )
{
*q++ = 0;
for( i=3; i<NI; i++ )
*q++ = *p--;
return;
}
#endif
for( i=2; i<NI; i++ )
*q++ = 0;
return;
}
#endif
/* clear high guard word */
*q++ = 0;
/* move in the significand */
for( i=0; i<NE-1; i++ )
*q++ = *p--;
/* clear low guard word */
*q = 0;
}
/*
; Add significands
; x + y replaces y
*/
void __eaddm(const short unsigned int * __restrict__ x,
short unsigned int * __restrict__ y)
{
register unsigned long a;
int i;
unsigned int carry;
x += NI-1;
y += NI-1;
carry = 0;
for( i=M; i<NI; i++ )
{
a = (unsigned long )(*x) + (unsigned long )(*y) + carry;
if( a & 0x10000 )
carry = 1;
else
carry = 0;
*y = (unsigned short )a;
--x;
--y;
}
}
/*
; Subtract significands
; y - x replaces y
*/
void __esubm(const short unsigned int * __restrict__ x,
short unsigned int * __restrict__ y)
{
unsigned long a;
int i;
unsigned int carry;
x += NI-1;
y += NI-1;
carry = 0;
for( i=M; i<NI; i++ )
{
a = (unsigned long )(*y) - (unsigned long )(*x) - carry;
if( a & 0x10000 )
carry = 1;
else
carry = 0;
*y = (unsigned short )a;
--x;
--y;
}
}
/* Multiply significand of e-type number b
by 16-bit quantity a, e-type result to c. */
static void __m16m(short unsigned int a,
short unsigned int * __restrict__ b,
short unsigned int * __restrict__ c)
{
register unsigned short *pp;
register unsigned long carry;
unsigned short *ps;
unsigned short p[NI];
unsigned long aa, m;
int i;
aa = a;
pp = &p[NI-2];
*pp++ = 0;
*pp = 0;
ps = &b[NI-1];
for( i=M+1; i<NI; i++ )
{
if( *ps == 0 )
{
--ps;
--pp;
*(pp-1) = 0;
}
else
{
m = (unsigned long) aa * *ps--;
carry = (m & 0xffff) + *pp;
*pp-- = (unsigned short )carry;
carry = (carry >> 16) + (m >> 16) + *pp;
*pp = (unsigned short )carry;
*(pp-1) = carry >> 16;
}
}
for( i=M; i<NI; i++ )
c[i] = p[i];
}
/* Divide significands. Neither the numerator nor the denominator
is permitted to have its high guard word nonzero. */
int __edivm(short unsigned int * __restrict__ den,
short unsigned int * __restrict__ num)
{
int i;
register unsigned short *p;
unsigned long tnum;
unsigned short j, tdenm, tquot;
unsigned short tprod[NI+1];
unsigned short equot[NI];
p = &equot[0];
*p++ = num[0];
*p++ = num[1];
for( i=M; i<NI; i++ )
{
*p++ = 0;
}
__eshdn1( num );
tdenm = den[M+1];
for( i=M; i<NI; i++ )
{
/* Find trial quotient digit (the radix is 65536). */
tnum = (((unsigned long) num[M]) << 16) + num[M+1];
/* Do not execute the divide instruction if it will overflow. */
if( (tdenm * 0xffffUL) < tnum )
tquot = 0xffff;
else
tquot = tnum / tdenm;
/* Prove that the divide worked. */
/*
tcheck = (unsigned long )tquot * tdenm;
if( tnum - tcheck > tdenm )
tquot = 0xffff;
*/
/* Multiply denominator by trial quotient digit. */
__m16m( tquot, den, tprod );
/* The quotient digit may have been overestimated. */
if( __ecmpm( tprod, num ) > 0 )
{
tquot -= 1;
__esubm( den, tprod );
if( __ecmpm( tprod, num ) > 0 )
{
tquot -= 1;
__esubm( den, tprod );
}
}
__esubm( tprod, num );
equot[i] = tquot;
__eshup6(num);
}
/* test for nonzero remainder after roundoff bit */
p = &num[M];
j = 0;
for( i=M; i<NI; i++ )
{
j |= *p++;
}
if( j )
j = 1;
for( i=0; i<NI; i++ )
num[i] = equot[i];
return( (int )j );
}
/* Multiply significands */
int __emulm(const short unsigned int * __restrict__ a,
short unsigned int * __restrict__ b)
{
const unsigned short *p;
unsigned short *q;
unsigned short pprod[NI];
unsigned short equot[NI];
unsigned short j;
int i;
equot[0] = b[0];
equot[1] = b[1];
for( i=M; i<NI; i++ )
equot[i] = 0;
j = 0;
p = &a[NI-1];
q = &equot[NI-1];
for( i=M+1; i<NI; i++ )
{
if( *p == 0 )
{
--p;
}
else
{
__m16m( *p--, b, pprod );
__eaddm(pprod, equot);
}
j |= *q;
__eshdn6(equot);
}
for( i=0; i<NI; i++ )
b[i] = equot[i];
/* return flag for lost nonzero bits */
return( (int)j );
}
/*
* Normalize and round off.
*
* The internal format number to be rounded is "s".
* Input "lost" indicates whether the number is exact.
* This is the so-called sticky bit.
*
* Input "subflg" indicates whether the number was obtained
* by a subtraction operation. In that case if lost is nonzero
* then the number is slightly smaller than indicated.
*
* Input "exp" is the biased exponent, which may be negative.
* the exponent field of "s" is ignored but is replaced by
* "exp" as adjusted by normalization and rounding.
*
* Input "rcntrl" is the rounding control.
*
* Input "rnprc" is precison control (64 or NBITS).
*/
void __emdnorm(short unsigned int *s, int lost, int subflg, long int exp, int rcntrl, int rndprc)
{
int i, j;
unsigned short r;
int rw = NI-1; /* low guard word */
int re = NI-2;
const unsigned short rmsk = 0xffff;
const unsigned short rmbit = 0x8000;
#if NE == 6
unsigned short rbit[NI] = {0,0,0,0,0,0,0,1,0};
#else
unsigned short rbit[NI] = {0,0,0,0,0,0,0,0,0,0,0,1,0};
#endif
/* Normalize */
j = __enormlz( s );
/* a blank significand could mean either zero or infinity. */
#ifndef INFINITY
if( j > NBITS )
{
__ecleazs( s );
return;
}
#endif
exp -= j;
#ifndef INFINITY
if( exp >= 32767L )
goto overf;
#else
if( (j > NBITS) && (exp < 32767L) )
{
__ecleazs( s );
return;
}
#endif
if( exp < 0L )
{
if( exp > (long )(-NBITS-1) )
{
j = (int )exp;
i = __eshift( s, j );
if( i )
lost = 1;
}
else
{
__ecleazs( s );
return;
}
}
/* Round off, unless told not to by rcntrl. */
if( rcntrl == 0 )
goto mdfin;
if (rndprc == 64)
{
rw = 7;
re = 6;
rbit[NI-2] = 0;
rbit[6] = 1;
}
/* Shift down 1 temporarily if the data structure has an implied
* most significant bit and the number is denormal.
* For rndprc = 64 or NBITS, there is no implied bit.
* But Intel long double denormals lose one bit of significance even so.
*/
#if IBMPC
if( (exp <= 0) && (rndprc != NBITS) )
#else
if( (exp <= 0) && (rndprc != 64) && (rndprc != NBITS) )
#endif
{
lost |= s[NI-1] & 1;
__eshdn1(s);
}
/* Clear out all bits below the rounding bit,
* remembering in r if any were nonzero.
*/
r = s[rw] & rmsk;
if( rndprc < NBITS )
{
i = rw + 1;
while( i < NI )
{
if( s[i] )
r |= 1;
s[i] = 0;
++i;
}
}
s[rw] &= ~rmsk;
if( (r & rmbit) != 0 )
{
if( r == rmbit )
{
if( lost == 0 )
{ /* round to even */
if( (s[re] & 1) == 0 )
goto mddone;
}
else
{
if( subflg != 0 )
goto mddone;
}
}
__eaddm( rbit, s );
}
mddone:
#if IBMPC
if( (exp <= 0) && (rndprc != NBITS) )
#else
if( (exp <= 0) && (rndprc != 64) && (rndprc != NBITS) )
#endif
{
__eshup1(s);
}
if( s[2] != 0 )
{ /* overflow on roundoff */
__eshdn1(s);
exp += 1;
}
mdfin:
s[NI-1] = 0;
if( exp >= 32767L )
{
#ifndef INFINITY
overf:
#endif
#ifdef INFINITY
s[1] = 32767;
for( i=2; i<NI-1; i++ )
s[i] = 0;
#else
s[1] = 32766;
s[2] = 0;
for( i=M+1; i<NI-1; i++ )
s[i] = 0xffff;
s[NI-1] = 0;
if( (rndprc < 64) || (rndprc == 113) )
s[rw] &= ~rmsk;
#endif
return;
}
if( exp < 0 )
s[1] = 0;
else
s[1] = (unsigned short )exp;
}
/*
; Multiply.
;
; unsigned short a[NE], b[NE], c[NE];
; emul( a, b, c ); c = b * a
*/
void __emul(const short unsigned int *a,
const short unsigned int *b,
short unsigned int *c)
{
unsigned short ai[NI], bi[NI];
int i, j;
long lt, lta, ltb;
#ifdef NANS
/* NaN times anything is the same NaN. */
if( __eisnan(a) )
{
__emov(a,c);
return;
}
if( __eisnan(b) )
{
__emov(b,c);
return;
}
/* Zero times infinity is a NaN. */
if( (__eisinf(a) && __eiiszero(b))
|| (__eisinf(b) && __eiiszero(a)) )
{
mtherr( "emul", DOMAIN );
__enan_NBITS( c );
return;
}
#endif
/* Infinity times anything else is infinity. */
#ifdef INFINITY
if( __eisinf(a) || __eisinf(b) )
{
if( __eisneg(a) ^ __eisneg(b) )
*(c+(NE-1)) = 0x8000;
else
*(c+(NE-1)) = 0;
__einfin(c);
return;
}
#endif
__emovi( a, ai );
__emovi( b, bi );
lta = ai[E];
ltb = bi[E];
if( ai[E] == 0 )
{
for( i=1; i<NI-1; i++ )
{
if( ai[i] != 0 )
{
lta -= __enormlz( ai );
goto mnzer1;
}
}
__eclear(c);
return;
}
mnzer1:
if( bi[E] == 0 )
{
for( i=1; i<NI-1; i++ )
{
if( bi[i] != 0 )
{
ltb -= __enormlz( bi );
goto mnzer2;
}
}
__eclear(c);
return;
}
mnzer2:
/* Multiply significands */
j = __emulm( ai, bi );
/* calculate exponent */
lt = lta + ltb - (EXONE - 1);
__emdnorm( bi, j, 0, lt, 64, NBITS );
/* calculate sign of product */
if( ai[0] == bi[0] )
bi[0] = 0;
else
bi[0] = 0xffff;
__emovo( bi, c );
}
/* move out internal format to ieee long double */
void __toe64(short unsigned int *a, short unsigned int *b)
{
register unsigned short *p, *q;
unsigned short i;
#ifdef NANS
if( __eiisnan(a) )
{
__enan_64( b );
return;
}
#endif
#ifdef IBMPC
/* Shift Intel denormal significand down 1. */
if( a[E] == 0 )
__eshdn1(a);
#endif
p = a;
#ifdef MIEEE
q = b;
#else
q = b + 4; /* point to output exponent */
#if 1
/* NOTE: if data type is 96 bits wide, clear the last word here. */
*(q+1)= 0;
#endif
#endif
/* combine sign and exponent */
i = *p++;
#ifdef MIEEE
if( i )
*q++ = *p++ | 0x8000;
else
*q++ = *p++;
*q++ = 0;
#else
if( i )
*q-- = *p++ | 0x8000;
else
*q-- = *p++;
#endif
/* skip over guard word */
++p;
/* move the significand */
#ifdef MIEEE
for( i=0; i<4; i++ )
*q++ = *p++;
#else
#ifdef INFINITY
if (__eiisinf (a))
{
/* Intel long double infinity. */
*q-- = 0x8000;
*q-- = 0;
*q-- = 0;
*q = 0;
return;
}
#endif
for( i=0; i<4; i++ )
*q-- = *p++;
#endif
}
/* Compare two e type numbers.
*
* unsigned short a[NE], b[NE];
* ecmp( a, b );
*
* returns +1 if a > b
* 0 if a == b
* -1 if a < b
* -2 if either a or b is a NaN.
*/
int __ecmp(const short unsigned int * __restrict__ a,
const short unsigned int * __restrict__ b)
{
unsigned short ai[NI], bi[NI];
register unsigned short *p, *q;
register int i;
int msign;
#ifdef NANS
if (__eisnan (a) || __eisnan (b))
return( -2 );
#endif
__emovi( a, ai );
p = ai;
__emovi( b, bi );
q = bi;
if( *p != *q )
{ /* the signs are different */
/* -0 equals + 0 */
for( i=1; i<NI-1; i++ )
{
if( ai[i] != 0 )
goto nzro;
if( bi[i] != 0 )
goto nzro;
}
return(0);
nzro:
if( *p == 0 )
return( 1 );
else
return( -1 );
}
/* both are the same sign */
if( *p == 0 )
msign = 1;
else
msign = -1;
i = NI-1;
do
{
if( *p++ != *q++ )
{
goto diff;
}
}
while( --i > 0 );
return(0); /* equality */
diff:
if( *(--p) > *(--q) )
return( msign ); /* p is bigger */
else
return( -msign ); /* p is littler */
}
/*
; Shift significand
;
; Shifts significand area up or down by the number of bits
; given by the variable sc.
*/
int __eshift(short unsigned int *x, int sc)
{
unsigned short lost;
unsigned short *p;
if( sc == 0 )
return( 0 );
lost = 0;
p = x + NI-1;
if( sc < 0 )
{
sc = -sc;
while( sc >= 16 )
{
lost |= *p; /* remember lost bits */
__eshdn6(x);
sc -= 16;
}
while( sc >= 8 )
{
lost |= *p & 0xff;
__eshdn8(x);
sc -= 8;
}
while( sc > 0 )
{
lost |= *p & 1;
__eshdn1(x);
sc -= 1;
}
}
else
{
while( sc >= 16 )
{
__eshup6(x);
sc -= 16;
}
while( sc >= 8 )
{
__eshup8(x);
sc -= 8;
}
while( sc > 0 )
{
__eshup1(x);
sc -= 1;
}
}
if( lost )
lost = 1;
return( (int )lost );
}
/*
; normalize
;
; Shift normalizes the significand area pointed to by argument
; shift count (up = positive) is returned.
*/
int __enormlz(short unsigned int *x)
{
register unsigned short *p;
int sc;
sc = 0;
p = &x[M];
if( *p != 0 )
goto normdn;
++p;
if( *p & 0x8000 )
return( 0 ); /* already normalized */
while( *p == 0 )
{
__eshup6(x);
sc += 16;
/* With guard word, there are NBITS+16 bits available.
* return true if all are zero.
*/
if( sc > NBITS )
return( sc );
}
/* see if high byte is zero */
while( (*p & 0xff00) == 0 )
{
__eshup8(x);
sc += 8;
}
/* now shift 1 bit at a time */
while( (*p & 0x8000) == 0)
{
__eshup1(x);
sc += 1;
if( sc > (NBITS+16) )
{
mtherr( "enormlz", UNDERFLOW );
return( sc );
}
}
return( sc );
/* Normalize by shifting down out of the high guard word
of the significand */
normdn:
if( *p & 0xff00 )
{
__eshdn8(x);
sc -= 8;
}
while( *p != 0 )
{
__eshdn1(x);
sc -= 1;
if( sc < -NBITS )
{
mtherr( "enormlz", OVERFLOW );
return( sc );
}
}
return( sc );
}
/* Move internal format number out,
* converting it to external format.
*/
void __emovo(const short unsigned int * __restrict__ a,
short unsigned int * __restrict__ b)
{
register const unsigned short *p;
register unsigned short *q;
unsigned short i;
p = a;
q = b + (NE-1); /* point to output exponent */
/* combine sign and exponent */
i = *p++;
if( i )
*q-- = *p++ | 0x8000;
else
*q-- = *p++;
#ifdef INFINITY
if( *(p-1) == 0x7fff )
{
#ifdef NANS
if( __eiisnan(a) )
{
__enan_NBITS( b );
return;
}
#endif
__einfin(b);
return;
}
#endif
/* skip over guard word */
++p;
/* move the significand */
for( i=0; i<NE-1; i++ )
*q-- = *p++;
}
#if USE_LDTOA
void __eiremain(short unsigned int *den, short unsigned int *num,
short unsigned int *equot )
{
long ld, ln;
unsigned short j;
ld = den[E];
ld -= __enormlz( den );
ln = num[E];
ln -= __enormlz( num );
__ecleaz( equot );
while( ln >= ld )
{
if( __ecmpm(den,num) <= 0 )
{
__esubm(den, num);
j = 1;
}
else
{
j = 0;
}
__eshup1(equot);
equot[NI-1] |= j;
__eshup1(num);
ln -= 1;
}
__emdnorm( num, 0, 0, ln, 0, NBITS );
}
void __eadd1(const short unsigned int * __restrict__ a,
const short unsigned int * __restrict__ b,
short unsigned int * __restrict__ c,
int subflg)
{
unsigned short ai[NI], bi[NI], ci[NI];
int i, lost, j, k;
long lt, lta, ltb;
#ifdef INFINITY
if( __eisinf(a) )
{
__emov(a,c);
if( subflg )
__eneg(c);
return;
}
if( __eisinf(b) )
{
__emov(b,c);
return;
}
#endif
__emovi( a, ai );
__emovi( b, bi );
if( sub )
ai[0] = ~ai[0];
/* compare exponents */
lta = ai[E];
ltb = bi[E];
lt = lta - ltb;
if( lt > 0L )
{ /* put the larger number in bi */
__emovz( bi, ci );
__emovz( ai, bi );
__emovz( ci, ai );
ltb = bi[E];
lt = -lt;
}
lost = 0;
if( lt != 0L )
{
if( lt < (long )(-NBITS-1) )
goto done; /* answer same as larger addend */
k = (int )lt;
lost = __eshift( ai, k ); /* shift the smaller number down */
}
else
{
/* exponents were the same, so must compare significands */
i = __ecmpm( ai, bi );
if( i == 0 )
{ /* the numbers are identical in magnitude */
/* if different signs, result is zero */
if( ai[0] != bi[0] )
{
__eclear(c);
return;
}
/* if same sign, result is double */
/* double denomalized tiny number */
if( (bi[E] == 0) && ((bi[3] & 0x8000) == 0) )
{
__eshup1( bi );
goto done;
}
/* add 1 to exponent unless both are zero! */
for( j=1; j<NI-1; j++ )
{
if( bi[j] != 0 )
{
/* This could overflow, but let emovo take care of that. */
ltb += 1;
break;
}
}
bi[E] = (unsigned short )ltb;
goto done;
}
if( i > 0 )
{ /* put the larger number in bi */
__emovz( bi, ci );
__emovz( ai, bi );
__emovz( ci, ai );
}
}
if( ai[0] == bi[0] )
{
__eaddm( ai, bi );
subflg = 0;
}
else
{
__esubm( ai, bi );
subflg = 1;
}
__emdnorm( bi, lost, subflg, ltb, 64, NBITS);
done:
__emovo( bi, c );
}
/* y = largest integer not greater than x
* (truncated toward minus infinity)
*
* unsigned short x[NE], y[NE]
*
* efloor( x, y );
*/
void __efloor(short unsigned int *x, short unsigned int *y)
{
register unsigned short *p;
int e, expon, i;
unsigned short f[NE];
const unsigned short bmask[] = {
0xffff,
0xfffe,
0xfffc,
0xfff8,
0xfff0,
0xffe0,
0xffc0,
0xff80,
0xff00,
0xfe00,
0xfc00,
0xf800,
0xf000,
0xe000,
0xc000,
0x8000,
0x0000,
};
__emov( x, f ); /* leave in external format */
expon = (int )f[NE-1];
e = (expon & 0x7fff) - (EXONE - 1);
if( e <= 0 )
{
__eclear(y);
goto isitneg;
}
/* number of bits to clear out */
e = NBITS - e;
__emov( f, y );
if( e <= 0 )
return;
p = &y[0];
while( e >= 16 )
{
*p++ = 0;
e -= 16;
}
/* clear the remaining bits */
*p &= bmask[e];
/* truncate negatives toward minus infinity */
isitneg:
if( (unsigned short )expon & (unsigned short )0x8000 )
{
for( i=0; i<NE-1; i++ )
{
if( f[i] != y[i] )
{
__esub( __eone, y, y );
break;
}
}
}
}
/*
; Subtract external format numbers.
;
; unsigned short a[NE], b[NE], c[NE];
; esub( a, b, c ); c = b - a
*/
void __esub(const short unsigned int * a,
const short unsigned int * b,
short unsigned int * c)
{
#ifdef NANS
if( __eisnan(a) )
{
__emov (a, c);
return;
}
if( __eisnan(b) )
{
__emov(b,c);
return;
}
/* Infinity minus infinity is a NaN.
* Test for subtracting infinities of the same sign.
*/
if( __eisinf(a) && __eisinf(b) && ((__eisneg (a) ^ __eisneg (b)) == 0))
{
mtherr( "esub", DOMAIN );
__enan_NBITS( c );
return;
}
#endif
__eadd1( a, b, c, 1 );
}
/*
; Divide.
;
; unsigned short a[NI], b[NI], c[NI];
; ediv( a, b, c ); c = b / a
*/
void __ediv(const short unsigned int *a,
const short unsigned int *b,
short unsigned int *c)
{
unsigned short ai[NI], bi[NI];
int i;
long lt, lta, ltb;
#ifdef NANS
/* Return any NaN input. */
if( __eisnan(a) )
{
__emov(a,c);
return;
}
if( __eisnan(b) )
{
__emov(b,c);
return;
}
/* Zero over zero, or infinity over infinity, is a NaN. */
if( (__eiszero(a) && __eiszero(b))
|| (__eisinf (a) && __eisinf (b)) )
{
mtherr( "ediv", DOMAIN );
__enan_NBITS( c );
return;
}
#endif
/* Infinity over anything else is infinity. */
#ifdef INFINITY
if( __eisinf(b) )
{
if( __eisneg(a) ^ __eisneg(b) )
*(c+(NE-1)) = 0x8000;
else
*(c+(NE-1)) = 0;
__einfin(c);
return;
}
if( __eisinf(a) )
{
__eclear(c);
return;
}
#endif
__emovi( a, ai );
__emovi( b, bi );
lta = ai[E];
ltb = bi[E];
if( bi[E] == 0 )
{ /* See if numerator is zero. */
for( i=1; i<NI-1; i++ )
{
if( bi[i] != 0 )
{
ltb -= __enormlz( bi );
goto dnzro1;
}
}
__eclear(c);
return;
}
dnzro1:
if( ai[E] == 0 )
{ /* possible divide by zero */
for( i=1; i<NI-1; i++ )
{
if( ai[i] != 0 )
{
lta -= __enormlz( ai );
goto dnzro2;
}
}
if( ai[0] == bi[0] )
*(c+(NE-1)) = 0;
else
*(c+(NE-1)) = 0x8000;
__einfin(c);
mtherr( "ediv", SING );
return;
}
dnzro2:
i = __edivm( ai, bi );
/* calculate exponent */
lt = ltb - lta + EXONE;
__emdnorm( bi, i, 0, lt, 64, NBITS );
/* set the sign */
if( ai[0] == bi[0] )
bi[0] = 0;
else
bi[0] = 0Xffff;
__emovo( bi, c );
}
void __e64toe(short unsigned int *pe, short unsigned int *y)
{
unsigned short yy[NI];
unsigned short *p, *q, *e;
int i;
e = pe;
p = yy;
for( i=0; i<NE-5; i++ )
*p++ = 0;
#ifdef IBMPC
for( i=0; i<5; i++ )
*p++ = *e++;
#endif
#ifdef DEC
for( i=0; i<5; i++ )
*p++ = *e++;
#endif
#ifdef MIEEE
p = &yy[0] + (NE-1);
*p-- = *e++;
++e;
for( i=0; i<4; i++ )
*p-- = *e++;
#endif
#ifdef IBMPC
/* For Intel long double, shift denormal significand up 1
-- but only if the top significand bit is zero. */
if((yy[NE-1] & 0x7fff) == 0 && (yy[NE-2] & 0x8000) == 0)
{
unsigned short temp[NI+1];
__emovi(yy, temp);
__eshup1(temp);
__emovo(temp,y);
return;
}
#endif
#ifdef INFINITY
/* Point to the exponent field. */
p = &yy[NE-1];
if( *p == 0x7fff )
{
#ifdef NANS
#ifdef IBMPC
for( i=0; i<4; i++ )
{
if((i != 3 && pe[i] != 0)
/* Check for Intel long double infinity pattern. */
|| (i == 3 && pe[i] != 0x8000))
{
__enan_NBITS( y );
return;
}
}
#else
for( i=1; i<=4; i++ )
{
if( pe[i] != 0 )
{
__enan_NBITS( y );
return;
}
}
#endif
#endif /* NANS */
__eclear( y );
__einfin( y );
if( *p & 0x8000 )
__eneg(y);
return;
}
#endif
p = yy;
q = y;
for( i=0; i<NE; i++ )
*q++ = *p++;
}
#endif /* USE_LDTOA */