From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55143) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YKplR-0002ai-22 for qemu-devel@nongnu.org; Mon, 09 Feb 2015 09:56:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YKplN-0006Wo-35 for qemu-devel@nongnu.org; Mon, 09 Feb 2015 09:56:41 -0500 Received: from mail-pa0-x233.google.com ([2607:f8b0:400e:c03::233]:51296) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YKplM-0006WU-So for qemu-devel@nongnu.org; Mon, 09 Feb 2015 09:56:37 -0500 Received: by mail-pa0-f51.google.com with SMTP id eu11so12577074pac.10 for ; Mon, 09 Feb 2015 06:56:35 -0800 (PST) From: Xiangyu Hu Date: Mon, 9 Feb 2015 14:56:07 +0000 Message-Id: <1423493767-3955-1-git-send-email-libhu.so@gmail.com> Subject: [Qemu-devel] [PATCH] softfloat: roundAndPackFloat16 should return FPInfinity and FPMaxNormal based on overflow_to_inf. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, alex.bennee@linaro.org, Xiangyu Hu Flag overflow_to_inf is specified by ARM manual to decide if FPInfinity(sign) or FPMaxNormal(sign) is returned. Current codepath fails to check it. Fixed by adding overflow_to_inf flag to return infinity when it's true and maxnormal otherwise. Signed-off-by: Xiangyu Hu --- fpu/softfloat.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fpu/softfloat.c b/fpu/softfloat.c index f1170fe..409a574 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -3377,6 +3377,7 @@ static float32 roundAndPackFloat16(flag zSign, int_fast16_t zExp, uint32_t increment; bool rounding_bumps_exp; bool is_tiny = false; + bool overflow_to_inf = false; /* Calculate the mask of bits of the mantissa which are not * representable in half-precision and will be lost. @@ -3398,18 +3399,23 @@ static float32 roundAndPackFloat16(flag zSign, int_fast16_t zExp, if ((zSig & mask) == increment) { increment = zSig & (increment << 1); } + overflow_to_inf = true; break; case float_round_ties_away: increment = (mask + 1) >> 1; + overflow_to_inf = true; break; case float_round_up: increment = zSign ? 0 : mask; + overflow_to_inf = (zSign == 0); break; case float_round_down: increment = zSign ? mask : 0; + overflow_to_inf = (zSign == 1); break; default: /* round_to_zero */ increment = 0; + overflow_to_inf = false; break; } @@ -3418,7 +3424,11 @@ static float32 roundAndPackFloat16(flag zSign, int_fast16_t zExp, if (zExp > maxexp || (zExp == maxexp && rounding_bumps_exp)) { if (ieee) { float_raise(float_flag_overflow | float_flag_inexact, status); - return packFloat16(zSign, 0x1f, 0); + if (overflow_to_inf) { + return packFloat16(zSign, 0x1f, 0); + } else { + return packFloat16(zSign, 0x1e, 0x3ff); + } } else { float_raise(float_flag_invalid, status); return packFloat16(zSign, 0x1f, 0x3ff); -- 1.9.1