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Re: [PATCH] Fix for logb/logbf/logbl (bz 13954/13955/13956)
I have also added the same change to the power7 files. Does it still
look good?
Thanks, Andreas.
* sysdeps/ieee754/dbl-64/s_logb.c (__logb): Optimize
handling of denormals.
* sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c (__logb): Likewise.
* sysdeps/ieee754/flt-32/s_logbf.c (__logbf): Likewise.
* sysdeps/ieee754/ldbl-96/s_logbl.c (__logbl): Likewise.
* sysdeps/ieee754/ldbl-128/s_logbl.c (__logbl): Likewise.
* sysdeps/ieee754/ldbl-128ibm/s_logbl.c (__logbl): Likewise.
* sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c (_logb): Likewise.
* sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c (_logbl):
Likewise.
---
sysdeps/ieee754/dbl-64/s_logb.c | 10 ++++++----
sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c | 4 ++--
sysdeps/ieee754/flt-32/s_logbf.c | 3 +--
sysdeps/ieee754/ldbl-128/s_logbl.c | 10 ++++++----
sysdeps/ieee754/ldbl-128ibm/s_logbl.c | 7 ++-----
sysdeps/ieee754/ldbl-96/s_logbl.c | 10 ++++++----
sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c | 13 +++++++------
sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c | 8 +++-----
8 files changed, 33 insertions(+), 32 deletions(-)
diff --git a/sysdeps/ieee754/dbl-64/s_logb.c b/sysdeps/ieee754/dbl-64/s_logb.c
index baa35e1..17aa94b 100644
--- a/sysdeps/ieee754/dbl-64/s_logb.c
+++ b/sysdeps/ieee754/dbl-64/s_logb.c
@@ -34,10 +34,12 @@ __logb (double x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
- int m1 = (ix == 0) ? 0 : __builtin_clz (ix);
- int m2 = (lx == 0) ? 0 : __builtin_clz (lx);
- int ma = (m1 == 0) ? m2 + 32 : m1;
- return -1022.0 + (double)(11 - ma);
+ int ma;
+ if (ix == 0)
+ ma = __builtin_clz (lx) + 32;
+ else
+ ma = __builtin_clz (ix);
+ rix -= ma - 12;
}
return (double) (rix - 1023);
}
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c
index 185dd05..40b8888 100644
--- a/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c
+++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_logb.c
@@ -36,8 +36,8 @@ __logb (double x)
return x * x;
if (__builtin_expect (ex == 0, 0))
{
- int m = (ix == 0) ? 0 : __builtin_clzll (ix);
- return -1022.0 + (double)(11 -m);
+ int m = __builtin_clzll (ix);
+ ex -= m - 12;
}
return (double) (ex - 1023);
}
diff --git a/sysdeps/ieee754/flt-32/s_logbf.c b/sysdeps/ieee754/flt-32/s_logbf.c
index 025c70d..e2b3aaa 100644
--- a/sysdeps/ieee754/flt-32/s_logbf.c
+++ b/sysdeps/ieee754/flt-32/s_logbf.c
@@ -31,8 +31,7 @@ __logbf (float x)
{
/* POSIX specifies that denormal number is treated as
though it were normalized. */
- int m = (ix == 0) ? 0 : __builtin_clz (ix);
- return -126.0 + (float)(8 - m);
+ rix -= __builtin_clz (ix) - 9;
}
return (float) (rix - 127);
}
diff --git a/sysdeps/ieee754/ldbl-128/s_logbl.c b/sysdeps/ieee754/ldbl-128/s_logbl.c
index cf6003e..3ba67b7 100644
--- a/sysdeps/ieee754/ldbl-128/s_logbl.c
+++ b/sysdeps/ieee754/ldbl-128/s_logbl.c
@@ -41,10 +41,12 @@ __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 -16382.0 + (long double)(15 - ma);
+ int ma;
+ if (hx == 0)
+ ma = __builtin_clzll (lx) + 64;
+ else
+ ma = __builtin_clzll (hx);
+ ex -= ma - 16;
}
return (long double) (ex - 16383);
}
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);
}
diff --git a/sysdeps/ieee754/ldbl-96/s_logbl.c b/sysdeps/ieee754/ldbl-96/s_logbl.c
index d8ad4bc..4289be1 100644
--- a/sysdeps/ieee754/ldbl-96/s_logbl.c
+++ b/sysdeps/ieee754/ldbl-96/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 = (ix == 0) ? 0 : __builtin_clz (ix);
- int m2 = (lx == 0) ? 0 : __builtin_clz (lx);
- int ma = (m1 == 0) ? m2 + 32 : m1;
- return -16382.0 - (long double)(ma);
+ int ma;
+ if (ix == 0)
+ ma = __builtin_clz (lx) + 32;
+ else
+ ma = __builtin_clz (ix);
+ es -= ma - 1;
}
return (long double) (es - 16383);
}
diff --git a/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c b/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c
index fba4822..87176c3 100644
--- a/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c
+++ b/sysdeps/powerpc/powerpc32/power7/fpu/s_logb.c
@@ -55,13 +55,14 @@ __logb (double x)
/* POSIX specifies that denormal numbers are treated as
though they were normalized. */
int32_t lx, ix;
- int m1, m2, ma;
+ int ma;
- EXTRACT_WORDS (ix , lx, x);
- m1 = (ix == 0) ? 0 : __builtin_clz (ix);
- m2 = (lx == 0) ? 0 : __builtin_clz (lx);
- ma = (m1 == 0) ? m2 + 32 : m1;
- return -1022.0 + (double)(11 - ma);
+ EXTRACT_WORDS (ix, lx, x);
+ if (ix == 0)
+ ma = __builtin_clz (lx) + 32;
+ else
+ ma = __builtin_clz (ix);
+ return (double) (-1023 - (ma - 12));
}
/* Test to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;
diff --git a/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c b/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c
index 03942ca..20c7d4e 100644
--- a/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c
+++ b/sysdeps/powerpc/powerpc32/power7/fpu/s_logbl.c
@@ -56,14 +56,12 @@ __logbl (long double x)
return (xh * xh);
else if (__builtin_expect (ret == two10m1, 0))
{
+ /* POSIX specifies that denormal number is treated as
+ though it were normalized. */
int64_t lx, hx;
- int m1, m2, ma;
GET_LDOUBLE_WORDS64 (hx, lx, x);
- m1 = (hx == 0) ? 0 : __builtin_clzll (hx);
- m2 = (lx == 0) ? 0 : __builtin_clzll (lx);
- ma = (m1 == 0) ? m2 + 64 : m1;
- return -1022.0 + (double)(11 - ma);
+ return (long double) (-1023 - (__builtin_clzll (hx) - 12));
}
/* Test to avoid logb_downward (0.0) == -0.0. */
return ret == -0.0 ? 0.0 : ret;
--
1.7.10.2
--
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."