* [PATCH] Convert 0.0/0.0 to NAN
@ 2017-04-19 23:50 Richard Allen
2017-04-20 0:01 ` Richard Allen
0 siblings, 1 reply; 3+ messages in thread
From: Richard Allen @ 2017-04-19 23:50 UTC (permalink / raw)
To: newlib
[-- Attachment #1: Type: text/plain, Size: 383 bytes --]
With newlib's default compiler flags(-O2 and whatnot),
the GCC I'm using creates calls to __aeabi_(f|d)div.
This causes a little extra register copying
and an unnecessary branch.
Additionally, __aeabi_?div may throw exceptions,
which is probably not what we want a
simple assignment to do.
Compiler version tested:
arm-none-eabi-gcc (15:5.4.1+svn241155-1) 5.4.1 20160919
-Richard
[-- Attachment #2: 0001-Convert-rint-to-rintf.patch --]
[-- Type: text/x-patch, Size: 1105 bytes --]
From 2369a552cf62dfb53f14978587a338072f6abd2c Mon Sep 17 00:00:00 2001
From: Richard <rsaxvc@rsaxvc.net>
Date: Wed, 19 Apr 2017 18:37:17 -0500
Subject: [PATCH] Convert rint() to rintf()
This was causing an unnecessary increase
in precision, as well as additional function
calls to do float->double conversion on
platforms with only a single-precision FPU.
---
newlib/libm/math/wf_pow.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/newlib/libm/math/wf_pow.c b/newlib/libm/math/wf_pow.c
index bd9de0ad0..5b79dd151 100644
--- a/newlib/libm/math/wf_pow.c
+++ b/newlib/libm/math/wf_pow.c
@@ -126,11 +126,11 @@
if (_LIB_VERSION == _SVID_) {
exc.retval = HUGE;
y *= 0.5;
- if(x<0.0&&rint(y)!=y) exc.retval = -HUGE;
+ if(x<0.0&&rintf(y)!=y) exc.retval = -HUGE;
} else {
exc.retval = HUGE_VAL;
y *= 0.5;
- if(x<0.0&&rint(y)!=y) exc.retval = -HUGE_VAL;
+ if(x<0.0&&rintf(y)!=y) exc.retval = -HUGE_VAL;
}
if (_LIB_VERSION == _POSIX_)
errno = ERANGE;
--
2.11.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Convert 0.0/0.0 to NAN
2017-04-19 23:50 [PATCH] Convert 0.0/0.0 to NAN Richard Allen
@ 2017-04-20 0:01 ` Richard Allen
2017-04-20 0:25 ` Craig Howland
0 siblings, 1 reply; 3+ messages in thread
From: Richard Allen @ 2017-04-20 0:01 UTC (permalink / raw)
To: newlib
[-- Attachment #1: Type: text/plain, Size: 542 bytes --]
Whoops, that was the wrong patch. Attached is correct patch.
On Wed, Apr 19, 2017 at 6:50 PM, Richard Allen <rsaxvc@rsaxvc.net> wrote:
> With newlib's default compiler flags(-O2 and whatnot),
> the GCC I'm using creates calls to __aeabi_(f|d)div.
> This causes a little extra register copying
> and an unnecessary branch.
>
> Additionally, __aeabi_?div may throw exceptions,
> which is probably not what we want a
> simple assignment to do.
>
> Compiler version tested:
> arm-none-eabi-gcc (15:5.4.1+svn241155-1) 5.4.1 20160919
>
> -Richard
[-- Attachment #2: 0001-Convert-0.0-0.0-to-NAN.patch --]
[-- Type: text/x-patch, Size: 6642 bytes --]
From 823701d0b25a00b892f55498f611a5222a1b80ee Mon Sep 17 00:00:00 2001
From: Richard <rsaxvc@rsaxvc.net>
Date: Wed, 19 Apr 2017 18:24:22 -0500
Subject: [PATCH 1/2] Convert 0.0/0.0 to NAN
With newlib's default compiler flags(-O2 and whatnot),
the GCC I'm using creates calls to __aeabi_fdiv
or __aeabi_ddiv. This causes a little extra
register allocation and an unnecessary branch.
Additionally, __aeabi_*div may throw exceptions,
which is almost certainly not what we want those
lines to do.
Compiler version tested:
arm-none-eabi-gcc (15:5.4.1+svn241155-1) 5.4.1 20160919
---
newlib/libm/math/w_acosh.c | 2 +-
newlib/libm/math/w_atanh.c | 2 +-
newlib/libm/math/w_fmod.c | 2 +-
newlib/libm/math/w_pow.c | 2 +-
newlib/libm/math/w_remainder.c | 2 +-
newlib/libm/math/w_sqrt.c | 2 +-
newlib/libm/math/wf_acosh.c | 2 +-
newlib/libm/math/wf_atanh.c | 2 +-
newlib/libm/math/wf_fmod.c | 2 +-
newlib/libm/math/wf_pow.c | 2 +-
newlib/libm/math/wf_remainder.c | 2 +-
newlib/libm/math/wf_sqrt.c | 2 +-
12 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/newlib/libm/math/w_acosh.c b/newlib/libm/math/w_acosh.c
index 93032600b..f40d9f291 100644
--- a/newlib/libm/math/w_acosh.c
+++ b/newlib/libm/math/w_acosh.c
@@ -106,7 +106,7 @@ MATHREF
exc.name = "acosh";
exc.err = 0;
exc.arg1 = exc.arg2 = x;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/w_atanh.c b/newlib/libm/math/w_atanh.c
index 07fd45962..9ffa29e48 100644
--- a/newlib/libm/math/w_atanh.c
+++ b/newlib/libm/math/w_atanh.c
@@ -106,7 +106,7 @@ QUICKREF
exc.name = "atanh";
exc.err = 0;
exc.arg1 = exc.arg2 = x;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/w_fmod.c b/newlib/libm/math/w_fmod.c
index f9f72c745..616a291bd 100644
--- a/newlib/libm/math/w_fmod.c
+++ b/newlib/libm/math/w_fmod.c
@@ -90,7 +90,7 @@ PORTABILITY
if (_LIB_VERSION == _SVID_)
exc.retval = x;
else
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/w_pow.c b/newlib/libm/math/w_pow.c
index ebf7be328..685507124 100644
--- a/newlib/libm/math/w_pow.c
+++ b/newlib/libm/math/w_pow.c
@@ -157,7 +157,7 @@ PORTABILITY
if (_LIB_VERSION == _SVID_)
exc.retval = 0.0;
else
- exc.retval = 0.0/0.0; /* X/Open allow NaN */
+ exc.retval = NAN; /* X/Open allow NaN */
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/w_remainder.c b/newlib/libm/math/w_remainder.c
index e4c196716..01245755c 100644
--- a/newlib/libm/math/w_remainder.c
+++ b/newlib/libm/math/w_remainder.c
@@ -74,7 +74,7 @@ PORTABILITY
exc.err = 0;
exc.arg1 = x;
exc.arg2 = y;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/w_sqrt.c b/newlib/libm/math/w_sqrt.c
index 23a793ce7..b2b1f8d78 100644
--- a/newlib/libm/math/w_sqrt.c
+++ b/newlib/libm/math/w_sqrt.c
@@ -76,7 +76,7 @@ PORTABILITY
if (_LIB_VERSION == _SVID_)
exc.retval = 0.0;
else
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_acosh.c b/newlib/libm/math/wf_acosh.c
index fc8ec3a0a..3c25447e8 100644
--- a/newlib/libm/math/wf_acosh.c
+++ b/newlib/libm/math/wf_acosh.c
@@ -41,7 +41,7 @@
exc.name = "acoshf";
exc.err = 0;
exc.arg1 = exc.arg2 = (double)x;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_atanh.c b/newlib/libm/math/wf_atanh.c
index 565630411..a6a0a28cf 100644
--- a/newlib/libm/math/wf_atanh.c
+++ b/newlib/libm/math/wf_atanh.c
@@ -41,7 +41,7 @@
exc.name = "atanhf";
exc.err = 0;
exc.arg1 = exc.arg2 = (double)x;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_fmod.c b/newlib/libm/math/wf_fmod.c
index 030ca3e7a..b14339a20 100644
--- a/newlib/libm/math/wf_fmod.c
+++ b/newlib/libm/math/wf_fmod.c
@@ -44,7 +44,7 @@
if (_LIB_VERSION == _SVID_)
exc.retval = x;
else
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_pow.c b/newlib/libm/math/wf_pow.c
index a30f8808e..bd9de0ad0 100644
--- a/newlib/libm/math/wf_pow.c
+++ b/newlib/libm/math/wf_pow.c
@@ -107,7 +107,7 @@
if (_LIB_VERSION == _SVID_)
exc.retval = 0.0;
else
- exc.retval = 0.0/0.0; /* X/Open allow NaN */
+ exc.retval = NAN; /* X/Open allow NaN */
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_remainder.c b/newlib/libm/math/wf_remainder.c
index f38c23785..48c395f9c 100644
--- a/newlib/libm/math/wf_remainder.c
+++ b/newlib/libm/math/wf_remainder.c
@@ -41,7 +41,7 @@
exc.err = 0;
exc.arg1 = (double)x;
exc.arg2 = (double)y;
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
diff --git a/newlib/libm/math/wf_sqrt.c b/newlib/libm/math/wf_sqrt.c
index 4536ba0ac..96814bd73 100644
--- a/newlib/libm/math/wf_sqrt.c
+++ b/newlib/libm/math/wf_sqrt.c
@@ -43,7 +43,7 @@
if (_LIB_VERSION == _SVID_)
exc.retval = 0.0;
else
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
--
2.11.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Convert 0.0/0.0 to NAN
2017-04-20 0:01 ` Richard Allen
@ 2017-04-20 0:25 ` Craig Howland
0 siblings, 0 replies; 3+ messages in thread
From: Craig Howland @ 2017-04-20 0:25 UTC (permalink / raw)
To: newlib
On 04/19/2017 08:01 PM, Richard Allen wrote:
> Whoops, that was the wrong patch. Attached is correct patch.
>
> On Wed, Apr 19, 2017 at 6:50 PM, Richard Allen <rsaxvc@rsaxvc.net> wrote:
>> With newlib's default compiler flags(-O2 and whatnot),
>> the GCC I'm using creates calls to __aeabi_(f|d)div.
>> This causes a little extra register copying
>> and an unnecessary branch.
>>
>> Additionally, __aeabi_?div may throw exceptions,
>> which is probably not what we want a
>> simple assignment to do.
>>
>> Compiler version tested:
>> arm-none-eabi-gcc (15:5.4.1+svn241155-1) 5.4.1 20160919
>>
>> -Richard
- exc.retval = 0.0/0.0;
+ exc.retval = NAN;
Well, actually, an exception is exactly why it is coded that way; yes, this is
what this simple assignment is intended to do. The 0.0/0.0 construct is used so
that at runtime the floating point flags gets set and yield the NAN result; a
floating point exception is supposed to be raised. (The compiler is not allowed
to optimize it away because of the side effects--which is why you're seeing the
divide even with -O2. Although I would guess that in an implementation which
does not have the side effects, the compiler would be able to substitute the NAN
at compile time.)
Craig
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-04-19 23:50 [PATCH] Convert 0.0/0.0 to NAN Richard Allen
2017-04-20 0:01 ` Richard Allen
2017-04-20 0:25 ` Craig Howland
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