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From: "krebbel1 at de dot ibm.com" <sourceware-bugzilla@sourceware.org> To: glibc-bugs@sourceware.org Subject: [Bug math/16427] ldbl-128 exp overflows to inf Date: Mon, 13 Jan 2014 13:28:00 -0000 [thread overview] Message-ID: <bug-16427-131-FnrSZfbgbg@http.sourceware.org/bugzilla/> (raw) In-Reply-To: <bug-16427-131@http.sourceware.org/bugzilla/> https://sourceware.org/bugzilla/show_bug.cgi?id=16427 --- Comment #4 from Andreas Krebbel <krebbel1 at de dot ibm.com> --- The code path in __ieee_expl reaches the statement: return TWO16383*x; The multiplication is performed using the mxbr hardware instruction dealing with FPR register pairs. At the end of the function the expected results were generated and can be printed correctly: => 0x3fffdf6117a <__ieee754_expl+78>: mxbr %f8,%f1 (gdb) 0x000003fffdf6117e 247 return TWO16383*x; 1: x/i $pc => 0x3fffdf6117e <__ieee754_expl+82>: std %f8,0(%r8) (gdb) p printf ("%Le %La\n", &{$f8, $f10}, &{$f8, $f10}) 1.189731e+4932 0x1.ffffffffffffffffffffffffffffp+16383 long double values are returned in memory, pointed to by r2: => 0x3fffdf611a0 <__ieee754_expl+116>: lmg %r8,%r15,320(%r15) (gdb) x/4xw $r2 0x3ffffffef78: 0x7ffeffff 0xffffffff 0xffffffff 0xffffffff (gdb) p printf ("%Le %La\n", $r2, $r2) 1.189731e+4932 0x1.ffffffffffffffffffffffffffffp+16383 $12 = 55 The code in k_standard.c:211 then seems to turn the value into "inf": case 206: /* exp(finite) overflow */ exc.type = OVERFLOW; exc.name = type < 100 ? "exp" : (type < 200 ? "expf" : "expl"); if (_LIB_VERSION == _SVID_) exc.retval = HUGE; else exc.retval = HUGE_VAL; if (_LIB_VERSION == _POSIX_) __set_errno (ERANGE); else if (!matherr(&exc)) { __set_errno (ERANGE); } break; -- You are receiving this mail because: You are on the CC list for the bug.
next prev parent reply other threads:[~2014-01-13 13:28 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-01-10 10:22 [Bug libc/16427] New: test-ldouble and test-ildoubl fail on S/390 krebbel1 at de dot ibm.com 2014-01-10 14:04 ` [Bug libc/16427] " joseph at codesourcery dot com 2014-01-10 15:08 ` [Bug math/16427] ldbl-128 exp overflows to inf krebbel1 at de dot ibm.com 2014-01-10 17:47 ` joseph at codesourcery dot com 2014-01-13 13:28 ` krebbel1 at de dot ibm.com [this message] 2014-01-13 13:30 ` krebbel1 at de dot ibm.com 2014-01-13 14:32 ` krebbel1 at de dot ibm.com 2014-01-13 15:54 ` joseph at codesourcery dot com 2014-01-15 8:51 ` cvs-commit at gcc dot gnu.org 2014-02-25 8:18 ` krebbel1 at de dot ibm.com 2014-02-25 8:19 ` krebbel1 at de dot ibm.com 2014-06-13 9:05 ` fweimer at redhat dot com
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