From patchwork Fri Mar 11 18:12:25 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 86442 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id EA857B6F0D for ; Sat, 12 Mar 2011 05:16:21 +1100 (EST) Received: from localhost ([127.0.0.1]:40655 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Py6st-0004Ly-2e for incoming@patchwork.ozlabs.org; Fri, 11 Mar 2011 13:16:19 -0500 Received: from [140.186.70.92] (port=46903 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Py6pM-0002yA-AF for qemu-devel@nongnu.org; Fri, 11 Mar 2011 13:12:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Py6pK-0005p2-SN for qemu-devel@nongnu.org; Fri, 11 Mar 2011 13:12:40 -0500 Received: from mnementh.archaic.org.uk ([81.2.115.146]:53506) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Py6pK-0005kF-J0 for qemu-devel@nongnu.org; Fri, 11 Mar 2011 13:12:38 -0500 Received: from pm215 by mnementh.archaic.org.uk with local (Exim 4.72) (envelope-from ) id 1Py6p9-0005kG-67; Fri, 11 Mar 2011 18:12:27 +0000 From: Peter Maydell To: qemu-devel@nongnu.org Date: Fri, 11 Mar 2011 18:12:25 +0000 Message-Id: <1299867146-22049-7-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.7.2.3 In-Reply-To: <1299867146-22049-1-git-send-email-peter.maydell@linaro.org> References: <1299867146-22049-1-git-send-email-peter.maydell@linaro.org> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 81.2.115.146 Cc: patches@linaro.org Subject: [Qemu-devel] [PATCH 6/7] softfloat: Add float*_min() and float*_max() functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Add min and max operations to softfloat. This allows us to implement propagation of NaNs and handling of negative zero correctly (unlike the approach of having target helper routines return one of the operands based on the result of a comparison op). Signed-off-by: Peter Maydell --- fpu/softfloat.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ fpu/softfloat.h | 4 ++++ 2 files changed, 53 insertions(+), 0 deletions(-) diff --git a/fpu/softfloat.c b/fpu/softfloat.c index 30b07e9..55f02ae 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -6052,6 +6052,55 @@ int float128_compare_quiet( float128 a, float128 b STATUS_PARAM ) return float128_compare_internal(a, b, 1 STATUS_VAR); } +/* min() and max() functions. These can't be implemented as + * 'compare and pick one input' because that would mishandle + * NaNs and +0 vs -0. + */ +#define MINMAX(s, nan_exp) \ +INLINE float ## s float ## s ## _minmax(float ## s a, float ## s b, \ + int ismin STATUS_PARAM ) \ +{ \ + flag aSign, bSign; \ + bits ## s av, bv; \ + a = float ## s ## _squash_input_denormal(a STATUS_VAR); \ + b = float ## s ## _squash_input_denormal(b STATUS_VAR); \ + if (float ## s ## _is_any_nan(a) || \ + float ## s ## _is_any_nan(b)) { \ + return propagateFloat ## s ## NaN(a, b STATUS_VAR); \ + } \ + aSign = extractFloat ## s ## Sign(a); \ + bSign = extractFloat ## s ## Sign(b); \ + av = float ## s ## _val(a); \ + bv = float ## s ## _val(b); \ + if (aSign != bSign) { \ + if (ismin) { \ + return aSign ? a : b; \ + } else { \ + return aSign ? b : a; \ + } \ + } else { \ + if (ismin) { \ + return (aSign ^ (av < bv)) ? a : b; \ + } else { \ + return (aSign ^ (av < bv)) ? b : a; \ + } \ + } \ +} \ + \ +float ## s float ## s ## _min(float ## s a, float ## s b STATUS_PARAM) \ +{ \ + return float ## s ## _minmax(a, b, 1 STATUS_VAR); \ +} \ + \ +float ## s float ## s ## _max(float ## s a, float ## s b STATUS_PARAM) \ +{ \ + return float ## s ## _minmax(a, b, 0 STATUS_VAR); \ +} + +MINMAX(32, 0xff) +MINMAX(64, 0x7ff) + + /* Multiply A by 2 raised to the power N. */ float32 float32_scalbn( float32 a, int n STATUS_PARAM ) { diff --git a/fpu/softfloat.h b/fpu/softfloat.h index fd61dc4..1d37d65 100644 --- a/fpu/softfloat.h +++ b/fpu/softfloat.h @@ -333,6 +333,8 @@ int float32_le_quiet( float32, float32 STATUS_PARAM ); int float32_lt_quiet( float32, float32 STATUS_PARAM ); int float32_compare( float32, float32 STATUS_PARAM ); int float32_compare_quiet( float32, float32 STATUS_PARAM ); +float32 float32_min(float32, float32 STATUS_PARAM); +float32 float32_max(float32, float32 STATUS_PARAM); int float32_is_quiet_nan( float32 ); int float32_is_signaling_nan( float32 ); float32 float32_maybe_silence_nan( float32 ); @@ -445,6 +447,8 @@ int float64_le_quiet( float64, float64 STATUS_PARAM ); int float64_lt_quiet( float64, float64 STATUS_PARAM ); int float64_compare( float64, float64 STATUS_PARAM ); int float64_compare_quiet( float64, float64 STATUS_PARAM ); +float64 float64_min(float64, float64 STATUS_PARAM); +float64 float64_max(float64, float64 STATUS_PARAM); int float64_is_quiet_nan( float64 a ); int float64_is_signaling_nan( float64 ); float64 float64_maybe_silence_nan( float64 );