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Re: [PATCH] Fix for logb/logbf/logbl (bz 13954/13955/13956)
Adhemerval Zanella <azanella@linux.vnet.ibm.com> writes:
> On 05/25/2012 01:20 PM, Adhemerval Zanella wrote:
>> On 05/25/2012 09:56 AM, Andreas Schwab wrote:
>>
>> diff --git a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
>> index 678b6ca..9b0bd98 100644
>> --- a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
>> +++ b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
>> @@ -38,10 +38,12 @@ __logbl (long double x)
>> {
>> /* POSIX specifies that denormal number is treated as
>> though it were normalized. */
>> - int m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
>> - int m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
>> - int ma = (m1 == 0) ? m2 + 64 : m1;
>> - return -1022.0 + (long double)(11 - ma);
>> + int ma;
>> + if (hx == 0)
>> + ma = __builtin_clzll (lx) + 64;
>> + else
>> + ma = __builtin_clzll (hx);
>> + rhx -= ma - 12;
>> }
>> return (long double) (rhx - 1023);
>> }
>>
> Based on your previous email I think only 'hx' should be considered as:
>
> + int ma = (hx == 0) ? 0 : __builtin_clzll (hx);
> + rhx -= ma - 12;
I think then the zero check at the top also only needs to look at hx:
diff --git a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
index 678b6ca..92ce2c1 100644
--- a/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/s_logbl.c
@@ -30,7 +30,7 @@ __logbl (long double x)
GET_LDOUBLE_WORDS64 (hx, lx, x);
hx &= 0x7fffffffffffffffLL; /* high |x| */
- if ((hx | (lx & 0x7fffffffffffffffLL)) == 0)
+ if (hx == 0)
return -1.0 / fabs (x);
if (hx >= 0x7ff0000000000000LL)
return x * x;
@@ -38,10 +38,7 @@ __logbl (long double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
- int m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
- int m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
- int ma = (m1 == 0) ? m2 + 64 : m1;
- return -1022.0 + (long double)(11 - ma);
+ rhx -= __builtin_clzll (hx) - 12;
}
return (long double) (rhx - 1023);
}
Andreas.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756 01D3 44D5 214B 8276 4ED5
"And now for something completely different."