From: Corinna Vinschen <corinna@vinschen.de>
Date: Mon, 16 Dec 2019 09:50:17 +0000 (+0100)
Subject: Cygwin: ilogbl: Make sure to return FP_ILGB0 on zero input
X-Git-Tag: cygwin-3_1_0-release~2
X-Git-Url: https://sourceware.org/git/?a=commitdiff_plain;h=29ba52da95532f61e2e15694245d5f25620e34b6;p=newlib-cygwin.git

Cygwin: ilogbl: Make sure to return FP_ILGB0 on zero input

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>
---

diff --git a/winsup/cygwin/math/ilogbl.S b/winsup/cygwin/math/ilogbl.S
index f68082ce6..a4fe503ad 100644
--- a/winsup/cygwin/math/ilogbl.S
+++ b/winsup/cygwin/math/ilogbl.S
@@ -23,6 +23,8 @@ __MINGW_USYMBOL(ilogbl):
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb	$0x40, %dh
+	je	2f		/* Is +-Inf, jump.  */
 
 	fxtract
 	pushq	%rax
@@ -37,6 +39,9 @@ __MINGW_USYMBOL(ilogbl):
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
+2:	fstp    %st
+	movl	$0x80000001, %eax	/* FP_ILOGB0  */
+	ret
 #else
 	fldt	4(%esp)
 /* I added the following ugly construct because ilogb(+-Inf) is
@@ -48,6 +53,8 @@ __MINGW_USYMBOL(ilogbl):
 	andb    %ah, %dh
 	cmpb    $0x05, %dh
 	je      1f		/* Is +-Inf, jump.  */
+	cmpb	$0x40, %dh
+	je	2f		/* Is +-Inf, jump.  */
 
 	fxtract
 	pushl	%eax
@@ -62,4 +69,7 @@ __MINGW_USYMBOL(ilogbl):
 1:	fstp	%st
 	movl	$0x7fffffff, %eax
 	ret
+2:	fstp    %st
+	movl	$0x80000001, %eax	/* FP_ILOGB0  */
+	ret
 #endif
diff --git a/winsup/cygwin/release/3.1.0 b/winsup/cygwin/release/3.1.0
index b0e845657..681ea5db9 100644
--- a/winsup/cygwin/release/3.1.0
+++ b/winsup/cygwin/release/3.1.0
@@ -108,3 +108,6 @@ Bug Fixes
 - Fix an assertion failure when /cygdrive contains an offline network
   drive.
   Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00016.html
+
+- Fix return value of ilogbl for 0 input.
+  Addresses: https://cygwin.com/ml/cygwin/2019-12/msg00074.html