From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:43319) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QCUOa-0008VS-T8 for qemu-devel@nongnu.org; Wed, 20 Apr 2011 06:12:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QCUOX-0004Sz-VQ for qemu-devel@nongnu.org; Wed, 20 Apr 2011 06:12:28 -0400 Received: from hall.aurel32.net ([88.191.126.93]:43747) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QCUOX-0004SP-PA for qemu-devel@nongnu.org; Wed, 20 Apr 2011 06:12:25 -0400 From: Aurelien Jarno Date: Wed, 20 Apr 2011 12:12:01 +0200 Message-Id: <1303294329-22634-13-git-send-email-aurelien@aurel32.net> In-Reply-To: <1303294329-22634-1-git-send-email-aurelien@aurel32.net> References: <1303294329-22634-1-git-send-email-aurelien@aurel32.net> Subject: [Qemu-devel] [PATCH v2 12/20] target-i386: fix helper_fxtract() wrt softfloat List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Aurelien Jarno With softfloat it's not possible to play with the overflow of an unsigned value to get the 0 case partially correct. Use a special case for that. Using a division to generate an infinity is the easiest way that works for both softfloat and softfloat-native. Reviewed-by: Peter Maydell Signed-off-by: Aurelien Jarno --- target-i386/op_helper.c | 23 ++++++++++++++++------- 1 files changed, 16 insertions(+), 7 deletions(-) diff --git a/target-i386/op_helper.c b/target-i386/op_helper.c index 22cb549..a4bf734 100644 --- a/target-i386/op_helper.c +++ b/target-i386/op_helper.c @@ -4005,15 +4005,24 @@ void helper_fpatan(void) void helper_fxtract(void) { CPU86_LDoubleU temp; - unsigned int expdif; temp.d = ST0; - expdif = EXPD(temp) - EXPBIAS; - /*DP exponent bias*/ - ST0 = expdif; - fpush(); - BIASEXPONENT(temp); - ST0 = temp.d; + + if (floatx_is_zero(ST0)) { + /* Easy way to generate -inf and raising division by 0 exception */ + ST0 = floatx_div(floatx_chs(floatx_one), floatx_zero, &env->fp_status); + fpush(); + ST0 = temp.d; + } else { + int expdif; + + expdif = EXPD(temp) - EXPBIAS; + /*DP exponent bias*/ + ST0 = int32_to_floatx(expdif, &env->fp_status); + fpush(); + BIASEXPONENT(temp); + ST0 = temp.d; + } } void helper_fprem1(void) -- 1.7.2.3