From patchwork Fri May 23 00:55:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Joseph Myers X-Patchwork-Id: 351686 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 978D9140082 for ; Fri, 23 May 2014 10:55:37 +1000 (EST) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:mime-version :content-type; q=dns; s=default; b=A9yPKYIVnffi7JHgAD6Fh4tsakH9m EhIr/M0Rq44+NIbwvfFj65VJR3RotQ/3NEklmFp5TZ5QVLE7H9OrPbjSqoE3YidV 7nvkPOnztEyEK5TtP0K8ob1ffFvQpUSC92NU9PMnVHTu3Y9IH5ZJZLoooveqhSUw Fb5WxNKTrFnR8E= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:date:from:to:subject:message-id:mime-version :content-type; s=default; bh=vPi8y4WXoShHJt2W2g03eoE9rfI=; b=hCq LM2jo/ChRkFRqrwNTk4PXwaaM50/QP+kSzkZ50k/KVbS2+6uypCfFvxQ3BTY47kS 9V5u1ygioS4Q4l7ATDut4JU8aUWaitPyaApgfCarIzkyAH7s6FzXs9DnDXEjihkv dan6UNZKwkbeTOpripglk8KNbgTxLeJ9rmQrr86U= Received: (qmail 5752 invoked by alias); 23 May 2014 00:55:30 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 5739 invoked by uid 89); 23 May 2014 00:55:29 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL, BAYES_00 autolearn=ham version=3.3.2 X-HELO: relay1.mentorg.com Date: Fri, 23 May 2014 00:55:20 +0000 From: "Joseph S. Myers" To: Subject: Fix log10 (1) in round-downward mode (bug 16977) Message-ID: MIME-Version: 1.0 As with various other issues of this kind, bug 16977 is log10 (1) wrongly returning -0 rather than +0 in round-downward mode because of an implementation effectively in terms of log1p (x - 1). This patch fixes the issue in the same way used for log. Tested x86_64 and x86 and ulps updated accordingly. Also tested for mips64 to confirm a fix was needed for ldbl-128 and to validate that fix (also applied to ldbl-128ibm since that version of logl is essentially the same as the ldbl-128 one). 2014-05-22 Joseph Myers [BZ #16977] * sysdeps/i386/fpu/e_log10.S (__ieee754_log10): Take absolute value when x - 1 is zero. * sysdeps/i386/fpu/e_log10f.S (__ieee754_log10f): Likewise. * sysdeps/i386/fpu/e_log10l.S (__ieee754_log10l): Likewise. * sysdeps/ieee754/ldbl-128/e_log10l.c (__ieee754_log10l): Return 0.0L for an argument of 1.0L. * sysdeps/ieee754/ldbl-128ibm/e_log10l.c (__ieee754_log10l): Likewise. * sysdeps/x86_64/fpu/e_log10l.S (__ieee754_log10l): Take absolute value when x - 1 is zero. * math/libm-test.inc (log10_test): Use ALL_RM_TEST. * sysdeps/i386/fpu/libm-test-ulps: Update. * sysdeps/x86_64/fpu/libm-test-ulps: Likewise. diff --git a/math/libm-test.inc b/math/libm-test.inc index de7bc8a..0d467a2 100644 --- a/math/libm-test.inc +++ b/math/libm-test.inc @@ -7798,9 +7798,7 @@ static const struct test_f_f_data log10_test_data[] = static void log10_test (void) { - START (log10, 0); - RUN_TEST_LOOP_f_f (log10, log10_test_data, ); - END; + ALL_RM_TEST (log10, 0, log10_test_data, RUN_TEST_LOOP_f_f, END); } diff --git a/sysdeps/i386/fpu/e_log10.S b/sysdeps/i386/fpu/e_log10.S index ce6a81a..1727708 100644 --- a/sysdeps/i386/fpu/e_log10.S +++ b/sysdeps/i386/fpu/e_log10.S @@ -46,7 +46,13 @@ ENTRY(__ieee754_log10) fnstsw // x-1 : x : log10(2) andb $0x45, %ah jz 2f - fstp %st(1) // x-1 : log10(2) + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 5f + fabs // log10(1) is +0 in all rounding modes. +5: fstp %st(1) // x-1 : log10(2) fyl2xp1 // log10(x) ret diff --git a/sysdeps/i386/fpu/e_log10f.S b/sysdeps/i386/fpu/e_log10f.S index 8c20723..72a3b88 100644 --- a/sysdeps/i386/fpu/e_log10f.S +++ b/sysdeps/i386/fpu/e_log10f.S @@ -47,7 +47,13 @@ ENTRY(__ieee754_log10f) fnstsw // x-1 : x : log10(2) andb $0x45, %ah jz 2f - fstp %st(1) // x-1 : log10(2) + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 5f + fabs // log10(1) is +0 in all rounding modes. +5: fstp %st(1) // x-1 : log10(2) fyl2xp1 // log10(x) ret diff --git a/sysdeps/i386/fpu/e_log10l.S b/sysdeps/i386/fpu/e_log10l.S index cde987b..45b9c6d 100644 --- a/sysdeps/i386/fpu/e_log10l.S +++ b/sysdeps/i386/fpu/e_log10l.S @@ -48,7 +48,13 @@ ENTRY(__ieee754_log10l) fnstsw // x-1 : x : log10(2) andb $0x45, %ah jz 2f - fstp %st(1) // x-1 : log10(2) + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 5f + fabs // log10(1) is +0 in all rounding modes. +5: fstp %st(1) // x-1 : log10(2) fyl2xp1 // log10(x) ret diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps index 946cad4..1e89284 100644 --- a/sysdeps/i386/fpu/libm-test-ulps +++ b/sysdeps/i386/fpu/libm-test-ulps @@ -1536,6 +1536,30 @@ Function: "log10": ildouble: 1 ldouble: 1 +Function: "log10_downward": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + +Function: "log10_towardzero": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + +Function: "log10_upward": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + Function: "log1p": ildouble: 1 ldouble: 1 diff --git a/sysdeps/ieee754/ldbl-128/e_log10l.c b/sysdeps/ieee754/ldbl-128/e_log10l.c index b403f81..618255f 100644 --- a/sysdeps/ieee754/ldbl-128/e_log10l.c +++ b/sysdeps/ieee754/ldbl-128/e_log10l.c @@ -193,6 +193,9 @@ __ieee754_log10l (long double x) if (hx >= 0x7fff000000000000LL) return (x + x); + if (x == 1.0L) + return 0.0L; + /* separate mantissa from exponent */ /* Note, frexp is used so that denormal numbers diff --git a/sysdeps/ieee754/ldbl-128ibm/e_log10l.c b/sysdeps/ieee754/ldbl-128ibm/e_log10l.c index 1a6a4a0..7477791 100644 --- a/sysdeps/ieee754/ldbl-128ibm/e_log10l.c +++ b/sysdeps/ieee754/ldbl-128ibm/e_log10l.c @@ -195,6 +195,9 @@ __ieee754_log10l (long double x) if (hx >= 0x7ff0000000000000LL) return (x + x); + if (x == 1.0L) + return 0.0L; + /* separate mantissa from exponent */ /* Note, frexp is used so that denormal numbers diff --git a/sysdeps/x86_64/fpu/e_log10l.S b/sysdeps/x86_64/fpu/e_log10l.S index 6c07024..2607ad1 100644 --- a/sysdeps/x86_64/fpu/e_log10l.S +++ b/sysdeps/x86_64/fpu/e_log10l.S @@ -46,7 +46,13 @@ ENTRY(__ieee754_log10l) fnstsw // x-1 : x : log10(2) andb $0x45, %ah jz 2f - fstp %st(1) // x-1 : log10(2) + fxam + fnstsw + andb $0x45, %ah + cmpb $0x40, %ah + jne 5f + fabs // log10(1) is +0 in all rounding modes. +5: fstp %st(1) // x-1 : log10(2) fyl2xp1 // log10(x) ret diff --git a/sysdeps/x86_64/fpu/libm-test-ulps b/sysdeps/x86_64/fpu/libm-test-ulps index d472876..bb549d2 100644 --- a/sysdeps/x86_64/fpu/libm-test-ulps +++ b/sysdeps/x86_64/fpu/libm-test-ulps @@ -1611,6 +1611,30 @@ ifloat: 2 ildouble: 1 ldouble: 1 +Function: "log10_downward": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + +Function: "log10_towardzero": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + +Function: "log10_upward": +double: 1 +float: 1 +idouble: 1 +ifloat: 1 +ildouble: 1 +ldouble: 1 + Function: "log1p": float: 1 ifloat: 1