[v3,1/4] iee754: provide gcc builtins based generic sqrt functions
Commit Message
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
---
sysdeps/generic/math-use-builtins.h | 3 +++
sysdeps/ieee754/dbl-64/e_sqrt.c | 6 ++++++
sysdeps/ieee754/flt-32/e_sqrtf.c | 16 ++++++++++------
sysdeps/s390/fpu/math-use-builtins.h | 3 +++
4 files changed, 22 insertions(+), 6 deletions(-)
Comments
s/iee754/ieee754/
Andreas.
On 6/3/20 1:46 AM, Andreas Schwab wrote:
> s/iee754/ieee754/
Fixed. Thx
On 03/06/2020 14:06, Vineet Gupta via Libc-alpha wrote:
> On 6/3/20 1:46 AM, Andreas Schwab wrote:
>> s/iee754/ieee754/
>
> Fixed. Thx
>
I think this patchset is ok, there is no need to send a v4. Do you
need someone to push it upstream for you?
On 6/3/20 10:09 AM, Adhemerval Zanella via Libc-alpha wrote:
> I think this patchset is ok, there is no need to send a v4. Do you
> need someone to push it upstream for you?
I do have write access to repo, I'll push it shortly.
Thx,
-Vineet
@@ -60,4 +60,7 @@
# define USE_COPYSIGNF128_BUILTIN 0
#endif
+#define USE_SQRT_BUILTIN 0
+#define USE_SQRTF_BUILTIN 0
+
#endif /* math-use-builtins.h */
@@ -41,6 +41,7 @@
#include <math_private.h>
#include <fenv_private.h>
#include <libm-alias-finite.h>
+#include <math-use-builtins.h>
/*********************************************************************/
/* An ultimate sqrt routine. Given an IEEE double machine number x */
@@ -50,6 +51,10 @@
double
__ieee754_sqrt (double x)
{
+#if USE_SQRT_BUILTIN
+ return __builtin_sqrt (x);
+#else
+ /* Use generic implementation. */
static const double
rt0 = 9.99999999859990725855365213134618E-01,
rt1 = 4.99999999495955425917856814202739E-01,
@@ -138,6 +143,7 @@ __ieee754_sqrt (double x)
return (x - x) / (x - x); /* sqrt(-ve)=sNaN */
return 0x1p-256 * __ieee754_sqrt (x * 0x1p512);
}
+#endif /* ! USE_SQRT_BUILTIN */
}
#ifndef __ieee754_sqrt
libm_alias_finite (__ieee754_sqrt, __sqrt)
@@ -16,12 +16,15 @@
#include <math.h>
#include <math_private.h>
#include <libm-alias-finite.h>
-
-static const float one = 1.0, tiny=1.0e-30;
+#include <math-use-builtins.h>
float
__ieee754_sqrtf(float x)
{
+#if USE_SQRTF_BUILTIN
+ return __builtin_sqrtf (x);
+#else
+ /* Use generic implementation. */
float z;
int32_t sign = (int)0x80000000;
int32_t ix,s,q,m,t,i;
@@ -70,10 +73,10 @@ __ieee754_sqrtf(float x)
/* use floating add to find out rounding direction */
if(ix!=0) {
- z = one-tiny; /* trigger inexact flag */
- if (z>=one) {
- z = one+tiny;
- if (z>one)
+ z = 0x1p0 - 0x1.4484cp-100; /* trigger inexact flag. */
+ if (z >= 0x1p0) {
+ z = 0x1p0 + 0x1.4484cp-100;
+ if (z > 0x1p0)
q += 2;
else
q += (q&1);
@@ -83,6 +86,7 @@ __ieee754_sqrtf(float x)
ix += (m <<23);
SET_FLOAT_WORD(z,ix);
return z;
+#endif /* ! USE_SQRTF_BUILTIN */
}
#ifndef __ieee754_sqrtf
libm_alias_finite (__ieee754_sqrtf, __sqrtf)
@@ -108,4 +108,7 @@
# define USE_COPYSIGNF128_BUILTIN 0
#endif
+#define USE_SQRT_BUILTIN 0
+#define USE_SQRTF_BUILTIN 0
+
#endif /* math-use-builtins.h */