* [PATCH 1/3] newlib/libm/common: Fix modf/modff returning snan
2020-03-26 0:18 NaN fixes in pow, powf, modf, modff Keith Packard
@ 2020-03-26 0:18 ` Keith Packard
2020-03-26 0:18 ` [PATCH 2/3] newlib/libm/common: Don't re-convert float to bits in modf/modff Keith Packard
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Keith Packard @ 2020-03-26 0:18 UTC (permalink / raw)
To: newlib
Recent GCC appears to elide multiplication by 1, which causes snan
parameters to be returned unchanged through *iptr. Use the existing
conversion of snan to qnan to also set the correct result in *iptr
instead.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
newlib/libm/common/s_modf.c | 10 ++--------
newlib/libm/common/sf_modf.c | 10 ++--------
2 files changed, 4 insertions(+), 16 deletions(-)
diff --git a/newlib/libm/common/s_modf.c b/newlib/libm/common/s_modf.c
index c948b8525..c826580b4 100644
--- a/newlib/libm/common/s_modf.c
+++ b/newlib/libm/common/s_modf.c
@@ -63,12 +63,6 @@ QUICKREF
#ifndef _DOUBLE_IS_32BITS
-#ifdef __STDC__
-static const double one = 1.0;
-#else
-static double one = 1.0;
-#endif
-
#ifdef __STDC__
double modf(double x, double *iptr)
#else
@@ -99,8 +93,8 @@ static double one = 1.0;
}
} else if (j0>51) { /* no fraction part */
__uint32_t high;
- *iptr = x*one;
- if (__fpclassifyd(x) == FP_NAN) return x+x; /* x is NaN, return NaN */
+ *iptr = x;
+ if (__fpclassifyd(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
GET_HIGH_WORD(high,x);
INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
return x;
diff --git a/newlib/libm/common/sf_modf.c b/newlib/libm/common/sf_modf.c
index ae970762b..e241e4612 100644
--- a/newlib/libm/common/sf_modf.c
+++ b/newlib/libm/common/sf_modf.c
@@ -15,12 +15,6 @@
#include "fdlibm.h"
-#ifdef __STDC__
-static const float one = 1.0;
-#else
-static float one = 1.0;
-#endif
-
#ifdef __STDC__
float modff(float x, float *iptr)
#else
@@ -51,8 +45,8 @@ static float one = 1.0;
}
} else { /* no fraction part */
__uint32_t ix;
- *iptr = x*one;
- if (__fpclassifyf(x) == FP_NAN) return x+x; /* x is NaN, return NaN */
+ *iptr = x;
+ if (__fpclassifyf(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
GET_FLOAT_WORD(ix,x);
SET_FLOAT_WORD(x,ix&0x80000000); /* return +-0 */
return x;
--
2.25.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 2/3] newlib/libm/common: Don't re-convert float to bits in modf/modff
2020-03-26 0:18 NaN fixes in pow, powf, modf, modff Keith Packard
2020-03-26 0:18 ` [PATCH 1/3] newlib/libm/common: Fix modf/modff returning snan Keith Packard
@ 2020-03-26 0:18 ` Keith Packard
2020-03-26 0:18 ` [PATCH 3/3] newlib/libm/math: Make pow/powf return qnan for snan arg Keith Packard
2020-03-26 11:42 ` NaN fixes in pow, powf, modf, modff Corinna Vinschen
3 siblings, 0 replies; 5+ messages in thread
From: Keith Packard @ 2020-03-26 0:18 UTC (permalink / raw)
To: newlib
These functions shared a pattern of re-converting the argument to bits
when returning +/-0. Skip that as the initial conversion still has the
sign bit.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
newlib/libm/common/s_modf.c | 12 +++---------
newlib/libm/common/sf_modf.c | 8 ++------
2 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/newlib/libm/common/s_modf.c b/newlib/libm/common/s_modf.c
index c826580b4..e552a9460 100644
--- a/newlib/libm/common/s_modf.c
+++ b/newlib/libm/common/s_modf.c
@@ -81,10 +81,8 @@ QUICKREF
} else {
i = (0x000fffff)>>j0;
if(((i0&i)|i1)==0) { /* x is integral */
- __uint32_t high;
*iptr = x;
- GET_HIGH_WORD(high,x);
- INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
+ INSERT_WORDS(x,i0&0x80000000,0); /* return +-0 */
return x;
} else {
INSERT_WORDS(*iptr,i0&(~i),0);
@@ -92,19 +90,15 @@ QUICKREF
}
}
} else if (j0>51) { /* no fraction part */
- __uint32_t high;
*iptr = x;
if (__fpclassifyd(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
- GET_HIGH_WORD(high,x);
- INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
+ INSERT_WORDS(x,i0&0x80000000,0); /* return +-0 */
return x;
} else { /* fraction part in low x */
i = ((__uint32_t)(0xffffffff))>>(j0-20);
if((i1&i)==0) { /* x is integral */
- __uint32_t high;
*iptr = x;
- GET_HIGH_WORD(high,x);
- INSERT_WORDS(x,high&0x80000000,0); /* return +-0 */
+ INSERT_WORDS(x,i0&0x80000000,0); /* return +-0 */
return x;
} else {
INSERT_WORDS(*iptr,i0,i1&(~i));
diff --git a/newlib/libm/common/sf_modf.c b/newlib/libm/common/sf_modf.c
index e241e4612..2994378bb 100644
--- a/newlib/libm/common/sf_modf.c
+++ b/newlib/libm/common/sf_modf.c
@@ -33,10 +33,8 @@
} else {
i = (0x007fffff)>>j0;
if((i0&i)==0) { /* x is integral */
- __uint32_t ix;
*iptr = x;
- GET_FLOAT_WORD(ix,x);
- SET_FLOAT_WORD(x,ix&0x80000000); /* return +-0 */
+ SET_FLOAT_WORD(x,i0&0x80000000); /* return +-0 */
return x;
} else {
SET_FLOAT_WORD(*iptr,i0&(~i));
@@ -44,11 +42,9 @@
}
}
} else { /* no fraction part */
- __uint32_t ix;
*iptr = x;
if (__fpclassifyf(x) == FP_NAN) return *iptr = x+x; /* x is NaN, return NaN */
- GET_FLOAT_WORD(ix,x);
- SET_FLOAT_WORD(x,ix&0x80000000); /* return +-0 */
+ SET_FLOAT_WORD(x,i0&0x80000000); /* return +-0 */
return x;
}
}
--
2.25.1
^ permalink raw reply [flat|nested] 5+ messages in thread* [PATCH 3/3] newlib/libm/math: Make pow/powf return qnan for snan arg
2020-03-26 0:18 NaN fixes in pow, powf, modf, modff Keith Packard
2020-03-26 0:18 ` [PATCH 1/3] newlib/libm/common: Fix modf/modff returning snan Keith Packard
2020-03-26 0:18 ` [PATCH 2/3] newlib/libm/common: Don't re-convert float to bits in modf/modff Keith Packard
@ 2020-03-26 0:18 ` Keith Packard
2020-03-26 11:42 ` NaN fixes in pow, powf, modf, modff Corinna Vinschen
3 siblings, 0 replies; 5+ messages in thread
From: Keith Packard @ 2020-03-26 0:18 UTC (permalink / raw)
To: newlib
The IEEE spec for pow only has special case for x**0 and 1**y when x/y
are quiet NaN. For signaling NaN, the general case applies and these functions
should signal the invalid exception and return a quiet NaN.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
newlib/libm/math/e_pow.c | 13 +++++++++----
newlib/libm/math/ef_pow.c | 10 +++++++---
2 files changed, 16 insertions(+), 7 deletions(-)
diff --git a/newlib/libm/math/e_pow.c b/newlib/libm/math/e_pow.c
index 5fd28e65f..4c450ec05 100644
--- a/newlib/libm/math/e_pow.c
+++ b/newlib/libm/math/e_pow.c
@@ -58,6 +58,8 @@
*/
#include "fdlibm.h"
+#include "math_config.h"
+
#if __OBSOLETE_MATH
#ifndef _DOUBLE_IS_32BITS
@@ -116,14 +118,17 @@ ivln2_l = 1.92596299112661746887e-08; /* 0x3E54AE0B, 0xF85DDF44 =1/ln2 tail*/
EXTRACT_WORDS(hy,ly,y);
ix = hx&0x7fffffff; iy = hy&0x7fffffff;
- /* y==zero: x**0 = 1 */
- if((iy|ly)==0) return one;
+ /* y==zero: x**0 = 1 unless x is snan */
+ if((iy|ly)==0) {
+ if (issignaling_inline(x)) return x + y;
+ return one;
+ }
/* x|y==NaN return NaN unless x==1 then return 1 */
if(ix > 0x7ff00000 || ((ix==0x7ff00000)&&(lx!=0)) ||
iy > 0x7ff00000 || ((iy==0x7ff00000)&&(ly!=0))) {
- if(((hx-0x3ff00000)|lx)==0) return one;
- else return nan("");
+ if(((hx-0x3ff00000)|lx)==0 && !issignaling_inline(y)) return one;
+ else return x + y;
}
/* determine if y is an odd int when x < 0
diff --git a/newlib/libm/math/ef_pow.c b/newlib/libm/math/ef_pow.c
index d9e85a95e..d4ea4c5e8 100644
--- a/newlib/libm/math/ef_pow.c
+++ b/newlib/libm/math/ef_pow.c
@@ -14,6 +14,7 @@
*/
#include "fdlibm.h"
+#include "math_config.h"
#if __OBSOLETE_MATH
#ifdef __v810__
@@ -74,13 +75,16 @@ ivln2_l = 7.0526075433e-06; /* 0x36eca570 =1/ln2 tail*/
ix = hx&0x7fffffff; iy = hy&0x7fffffff;
/* y==zero: x**0 = 1 */
- if(FLT_UWORD_IS_ZERO(iy)) return one;
+ if(FLT_UWORD_IS_ZERO(iy)) {
+ if (issignalingf_inline(x)) return x + y;
+ return one;
+ }
/* x|y==NaN return NaN unless x==1 then return 1 */
if(FLT_UWORD_IS_NAN(ix) ||
FLT_UWORD_IS_NAN(iy)) {
- if(hx==0x3f800000) return one;
- else return nanf("");
+ if(hx==0x3f800000 && !issignalingf_inline(y)) return one;
+ else return x + y;
}
/* determine if y is an odd int when x < 0
--
2.25.1
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: NaN fixes in pow, powf, modf, modff
2020-03-26 0:18 NaN fixes in pow, powf, modf, modff Keith Packard
` (2 preceding siblings ...)
2020-03-26 0:18 ` [PATCH 3/3] newlib/libm/math: Make pow/powf return qnan for snan arg Keith Packard
@ 2020-03-26 11:42 ` Corinna Vinschen
3 siblings, 0 replies; 5+ messages in thread
From: Corinna Vinschen @ 2020-03-26 11:42 UTC (permalink / raw)
To: Keith Packard; +Cc: newlib
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On Mar 25 17:18, Keith Packard via Newlib wrote:
> The first patch makes modf set *iptr to qnan when provided an snan
> parameter, which wasn't happening on ARM softfp because GCC elided the
> * 1.0 operation.
>
> The second patch cleans up modf/modff by not re-converting the float
> to bits before extracting the sign bit.
>
> The third patch makes pow return qnan instead of 1.0 when the
> parameter is snan.
>
> These functions now match glibc for all of my tests, which were
> derived from the IEEE requirements.
>
Pushed.
Thanks,
Corinna
--
Corinna Vinschen
Cygwin Maintainer
Red Hat
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^ permalink raw reply [flat|nested] 5+ messages in thread