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* [Bug math/14470] New: Inaccurate j1f function on x86_32
@ 2012-08-15 14:10 liubov.dmitrieva at gmail dot com
2012-08-15 14:39 ` [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64 liubov.dmitrieva at gmail dot com
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: liubov.dmitrieva at gmail dot com @ 2012-08-15 14:10 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=14470
Bug #: 14470
Summary: Inaccurate j1f function on x86_32
Product: glibc
Version: 2.17
Status: NEW
Severity: normal
Priority: P2
Component: math
AssignedTo: unassigned@sourceware.org
ReportedBy: liubov.dmitrieva@gmail.com
Classification: Unclassified
Test case:
// gcc main.c -std=c99 -lm -m32
#include <stdio.h>
#include <fenv.h>
#include <stdlib.h> // abs function for int argument
extern float j1f(float);
extern double j1(double);
#define i32(a) (((int*)&(a))[0])
int main() {
float a,r1,r2;
i32(a)=0x4122c68a; //argument
fesetround(FE_TONEAREST);
r1 = j1f(a); //actual result
r2 = j1(a); //actual result 2
printf("inputs: a = (0x%08x)\t%e\n", i32(a), a);
printf("actual = (0x%08x)\t%.13e\n", i32(r1), r1);
printf("expected = (0x%08x)\t%.13e\n", i32(r2), r2);
printf("error = %d ulp\n", abs(i32(r1) - i32(r2)));
return 0;
}
Results:
inputs: a = (0x4122c68a) 1.017347e+01
actual = (0xb55e2ad3) -8.2763762065952e-07
expected = (0xb55e40c6) -8.2795702383009e-07
error = 5619 ulp
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* [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
@ 2012-08-15 14:39 ` liubov.dmitrieva at gmail dot com
2012-08-16 8:12 ` liubov.dmitrieva at gmail dot com
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: liubov.dmitrieva at gmail dot com @ 2012-08-15 14:39 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=14470
Liubov Dmitrieva <liubov.dmitrieva at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Inaccurate j1f function on |Inaccurate j1f function on
|x86_32 |x86_32 and x86_64
--- Comment #1 from Liubov Dmitrieva <liubov.dmitrieva at gmail dot com> 2012-08-15 14:38:56 UTC ---
In bug description result 5619 ulps was the result for x86_64 and for 32 bit
mode
result is:
-bash-4.2$ gcc main_j1f.c -lm -odo -m32
-bash-4.2$ ./do
inputs: a = (0x4122c68a) 1.017347e+01
actual = (0xb55e4d6d) -8.2814113966378e-07
expected = (0xb55e40c6) -8.2795702383009e-07
error = 3239 ulp
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* [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
2012-08-15 14:39 ` [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64 liubov.dmitrieva at gmail dot com
@ 2012-08-16 8:12 ` liubov.dmitrieva at gmail dot com
2014-02-06 18:31 ` [Bug math/14470] Inaccurate j1f function jsm28 at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: liubov.dmitrieva at gmail dot com @ 2012-08-16 8:12 UTC (permalink / raw)
To: glibc-bugs
http://sourceware.org/bugzilla/show_bug.cgi?id=14470
--- Comment #2 from Liubov Dmitrieva <liubov.dmitrieva at gmail dot com> 2012-08-16 08:11:45 UTC ---
represent the test argument using a hex float value, test case update:
#include <stdio.h>
#include <math.h>
#include <fenv.h>
extern float j1f(float);
extern double j1(double);
int main() {
float a,r1;
double r2;
a=0x1.458d14p3; //argument
fesetround(FE_TONEAREST);
r1 = j1f(a); //actual result
r2 = j1(a); //actual result 2
printf("inputs: a = %.6a\n", a);
printf("actual = %.6a\n", r1);
printf("expected = %.6a\n", r2);
printf("error = %f ulp\n", fabs(r1 - r2) * exp2(23.0-logbf(r1)));
return 0;
}
Result x86:
inputs: a = 0x1.458d14p+3
actual = -0x1.bc9adap-21
expected = -0x1.bc818dp-21
error = 3238.561446 ulp
Result x86_64:
inputs: a = 0x1.458d14p+3
actual = -0x1.bc55a6p-21
expected = -0x1.bc818dp-21
error = 5619.438563 ulp
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* [Bug math/14470] Inaccurate j1f function
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
2012-08-15 14:39 ` [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64 liubov.dmitrieva at gmail dot com
2012-08-16 8:12 ` liubov.dmitrieva at gmail dot com
@ 2014-02-06 18:31 ` jsm28 at gcc dot gnu.org
2014-06-17 18:39 ` fweimer at redhat dot com
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: jsm28 at gcc dot gnu.org @ 2014-02-06 18:31 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=14470
Joseph Myers <jsm28 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|Inaccurate j1f function on |Inaccurate j1f function
|x86_32 and x86_64 |
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* [Bug math/14470] Inaccurate j1f function
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
` (2 preceding siblings ...)
2014-02-06 18:31 ` [Bug math/14470] Inaccurate j1f function jsm28 at gcc dot gnu.org
@ 2014-06-17 18:39 ` fweimer at redhat dot com
2020-08-06 10:45 ` zimmerma+gcc at loria dot fr
2021-04-02 4:24 ` zimmerma+gcc at loria dot fr
5 siblings, 0 replies; 7+ messages in thread
From: fweimer at redhat dot com @ 2014-06-17 18:39 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=14470
Florian Weimer <fweimer at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Flags| |security-
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* [Bug math/14470] Inaccurate j1f function
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
` (3 preceding siblings ...)
2014-06-17 18:39 ` fweimer at redhat dot com
@ 2020-08-06 10:45 ` zimmerma+gcc at loria dot fr
2021-04-02 4:24 ` zimmerma+gcc at loria dot fr
5 siblings, 0 replies; 7+ messages in thread
From: zimmerma+gcc at loria dot fr @ 2020-08-06 10:45 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=14470
--- Comment #4 from Paul Zimmermann <zimmerma+gcc at loria dot fr> ---
with glibc-2.32, the maximum error on x86_64 is now 2246675 ulps (for
x=1.892188179e+38)
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* [Bug math/14470] Inaccurate j1f function
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
` (4 preceding siblings ...)
2020-08-06 10:45 ` zimmerma+gcc at loria dot fr
@ 2021-04-02 4:24 ` zimmerma+gcc at loria dot fr
5 siblings, 0 replies; 7+ messages in thread
From: zimmerma+gcc at loria dot fr @ 2021-04-02 4:24 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=14470
Paul Zimmermann <zimmerma+gcc at loria dot fr> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |FIXED
Status|NEW |RESOLVED
Target Milestone|--- |2.34
--- Comment #5 from Paul Zimmermann <zimmerma+gcc at loria dot fr> ---
fixed by commit 9acda61
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-- links below jump to the message on this page --
2012-08-15 14:10 [Bug math/14470] New: Inaccurate j1f function on x86_32 liubov.dmitrieva at gmail dot com
2012-08-15 14:39 ` [Bug math/14470] Inaccurate j1f function on x86_32 and x86_64 liubov.dmitrieva at gmail dot com
2012-08-16 8:12 ` liubov.dmitrieva at gmail dot com
2014-02-06 18:31 ` [Bug math/14470] Inaccurate j1f function jsm28 at gcc dot gnu.org
2014-06-17 18:39 ` fweimer at redhat dot com
2020-08-06 10:45 ` zimmerma+gcc at loria dot fr
2021-04-02 4:24 ` zimmerma+gcc at loria dot fr
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