From patchwork Tue Aug 21 04:33:30 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Gibson X-Patchwork-Id: 10570975 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 750C7920 for ; Tue, 21 Aug 2018 04:42:26 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 645F2299F4 for ; Tue, 21 Aug 2018 04:42:26 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 585E029E1C; Tue, 21 Aug 2018 04:42:26 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id E7654299F4 for ; Tue, 21 Aug 2018 04:42:25 +0000 (UTC) Received: from localhost ([::1]:50685 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fryUr-0003mL-5w for patchwork-qemu-devel@patchwork.kernel.org; Tue, 21 Aug 2018 00:42:25 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56505) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fryMt-0004Bj-P0 for qemu-devel@nongnu.org; Tue, 21 Aug 2018 00:34:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fryMo-0000Mg-WD for qemu-devel@nongnu.org; Tue, 21 Aug 2018 00:34:09 -0400 Received: from ozlabs.org ([2401:3900:2:1::2]:39495) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fryMk-0000EZ-NT; Tue, 21 Aug 2018 00:34:05 -0400 Received: by ozlabs.org (Postfix, from userid 1007) id 41vd9D3FRcz9s8T; Tue, 21 Aug 2018 14:33:51 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gibson.dropbear.id.au; s=201602; t=1534826032; bh=G3e+S+2w+W6fKwuLScOLzB6nQqulR8QVBOydqj85YAw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m0r4mfkA800pRp4hzDPou9UjSvvZIODawSQ61bnEUI+UTJJrNV4h0LRZnMLB+/NGr UTm4sIlkMouLX9M8CyNf0Y8ajx0Zqbyf42ttRML/7x6WRe6yd+ltafrZWapyeGQPe4 GQFaX0H1FrrRIOsEkQ4bYr9zLA2F9WbaxwgUGtGY= From: David Gibson To: peter.maydell@linaro.org Date: Tue, 21 Aug 2018 14:33:30 +1000 Message-Id: <20180821043343.7514-14-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180821043343.7514-1-david@gibson.dropbear.id.au> References: <20180821043343.7514-1-david@gibson.dropbear.id.au> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2401:3900:2:1::2 Subject: [Qemu-devel] [PULL 13/26] target/ppc: simplify bcdadd/sub functions X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: lvivier@redhat.com, aik@ozlabs.ru, groug@kaod.org, qemu-devel@nongnu.org, Yasmin Beatriz , qemu-ppc@nongnu.org, clg@kaod.org, David Gibson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Yasmin Beatriz After solving a corner case in bcdsub, this patch simplifies the logic of both bcdadd/sub instructions by removing some unnecessary local flags. This commit also rearranges some if-else conditions in bcdadd to make it easier to read. Signed-off-by: Yasmin Beatriz Signed-off-by: David Gibson --- target/ppc/int_helper.c | 49 +++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 31 deletions(-) diff --git a/target/ppc/int_helper.c b/target/ppc/int_helper.c index ac7f92d7ae..fcac90a4a9 100644 --- a/target/ppc/int_helper.c +++ b/target/ppc/int_helper.c @@ -2671,16 +2671,14 @@ static int bcd_cmp_mag(ppc_avr_t *a, ppc_avr_t *b) return 0; } -static int bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, +static void bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, int *overflow) { int carry = 0; int i; - int is_zero = 1; for (i = 1; i <= 31; i++) { uint8_t digit = bcd_get_digit(a, i, invalid) + bcd_get_digit(b, i, invalid) + carry; - is_zero &= (digit == 0); if (digit > 9) { carry = 1; digit -= 10; @@ -2689,26 +2687,20 @@ static int bcd_add_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, } bcd_put_digit(t, digit, i); - - if (unlikely(*invalid)) { - return -1; - } } *overflow = carry; - return is_zero; } -static int bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, +static void bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, int *overflow) { int carry = 0; int i; - int is_zero = 1; + for (i = 1; i <= 31; i++) { uint8_t digit = bcd_get_digit(a, i, invalid) - bcd_get_digit(b, i, invalid) + carry; - is_zero &= (digit == 0); if (digit & 0x80) { carry = -1; digit += 10; @@ -2717,14 +2709,9 @@ static int bcd_sub_mag(ppc_avr_t *t, ppc_avr_t *a, ppc_avr_t *b, int *invalid, } bcd_put_digit(t, digit, i); - - if (unlikely(*invalid)) { - return -1; - } } *overflow = carry; - return is_zero; } uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) @@ -2734,26 +2721,28 @@ uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) int sgnb = bcd_get_sgn(b); int invalid = (sgna == 0) || (sgnb == 0); int overflow = 0; - int zero = 0; uint32_t cr = 0; ppc_avr_t result = { .u64 = { 0, 0 } }; if (!invalid) { if (sgna == sgnb) { result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); - zero = bcd_add_mag(&result, a, b, &invalid, &overflow); - cr = (sgna > 0) ? CRF_GT : CRF_LT; - } else if (bcd_cmp_mag(a, b) > 0) { - result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); - zero = bcd_sub_mag(&result, a, b, &invalid, &overflow); - cr = (sgna > 0) ? CRF_GT : CRF_LT; - } else if (bcd_cmp_mag(a, b) == 0) { - result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(0, ps); - zero = bcd_sub_mag(&result, b, a, &invalid, &overflow); + bcd_add_mag(&result, a, b, &invalid, &overflow); + cr = bcd_cmp_zero(&result); } else { - result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgnb, ps); - zero = bcd_sub_mag(&result, b, a, &invalid, &overflow); - cr = (sgnb > 0) ? CRF_GT : CRF_LT; + int magnitude = bcd_cmp_mag(a, b); + if (magnitude > 0) { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgna, ps); + bcd_sub_mag(&result, a, b, &invalid, &overflow); + cr = (sgna > 0) ? CRF_GT : CRF_LT; + } else if (magnitude < 0) { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(sgnb, ps); + bcd_sub_mag(&result, b, a, &invalid, &overflow); + cr = (sgnb > 0) ? CRF_GT : CRF_LT; + } else { + result.u8[BCD_DIG_BYTE(0)] = bcd_preferred_sgn(0, ps); + cr = CRF_EQ; + } } } @@ -2762,8 +2751,6 @@ uint32_t helper_bcdadd(ppc_avr_t *r, ppc_avr_t *a, ppc_avr_t *b, uint32_t ps) cr = CRF_SO; } else if (overflow) { cr |= CRF_SO; - } else if (zero) { - cr = CRF_EQ; } *r = result;