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(emdnorm, toe64, etoe64): Significand of Intel long double denormals 

is shifted down one bit.

From-SVN: r9578
This commit is contained in:
Richard Kenner 1995-05-05 07:10:06 -04:00
parent 0e8c917222
commit d730ef29fb
1 changed files with 23 additions and 3 deletions
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26
gcc/real.c
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@ -2367,8 +2367,10 @@ emdnorm (s, lost, subflg, exp, rcntrl)
}
/* Shift down 1 temporarily if the data structure has an implied
most significant bit and the number is denormal. */
if ((exp <= 0) && (rndprc != 64) && (rndprc != NBITS))
most significant bit and the number is denormal.
Intel long double denormals also lose one bit of precision. */
if ((exp <= 0) && (rndprc != NBITS)
&& ((rndprc != 64) || ((rndprc == 64) && ! REAL_WORDS_BIG_ENDIAN)))
{
lost |= s[NI - 1] & 1;
eshdn1 (s);
@ -2406,7 +2408,9 @@ emdnorm (s, lost, subflg, exp, rcntrl)
eaddm (rbit, s);
}
mddone:
if ((exp <= 0) && (rndprc != 64) && (rndprc != NBITS))
/* Undo the temporary shift for denormal values. */
if ((exp <= 0) && (rndprc != NBITS)
&& ((rndprc != 64) || ((rndprc == 64) && ! REAL_WORDS_BIG_ENDIAN)))
{
eshup1 (s);
}
@ -2948,6 +2952,19 @@ e64toe (pe, y)
{
for (i = 0; i < 5; i++)
*p++ = *e++;
/* For denormal long double Intel format, shift significand up one
-- but only if the top significand bit is zero. A top bit of 1
is "pseudodenormal" when the exponent is zero. */
if((yy[NE-1] & 0x7fff) == 0 && (yy[NE-2] & 0x8000) == 0)
{
unsigned EMUSHORT temp[NI];
emovi(yy, temp);
eshup1(temp);
emovo(temp,y);
return;
}
}
else
{
@ -3323,6 +3340,9 @@ toe64 (a, b)
return;
}
#endif
/* Shift denormal long double Intel format significand down one bit. */
if ((a[E] == 0) && ! REAL_WORDS_BIG_ENDIAN)
eshdn1 (a);
p = a;
#ifdef IBM
q = b;