From patchwork Wed Dec 21 23:06:03 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 18628 Received: (qmail 52855 invoked by alias); 21 Dec 2016 23:06:34 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Delivered-To: mailing list libc-alpha@sourceware.org Received: (qmail 52465 invoked by uid 89); 21 Dec 2016 23:06:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.6 required=5.0 tests=BAYES_00, FREEMAIL_ENVFROM_END_DIGIT, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, SPF_PASS autolearn=no version=3.3.2 spammy=Identify, 1, 69 X-HELO: mail-pg0-f67.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:subject:date:message-id :in-reply-to:references; bh=E8oUu6lmdT2mvwjQwOqcrSDaHUOWjgqYx9M6zGpQUsw=; b=C6YgE0o42QlFDym5xDPOYOub5dLf9ie7aPYoB/V0Y+0n+u3hNVHRxIXlzhQHieaxZP xTTpxrhQVC07Pe3CuYVOjKoubdlQzh63yetj+/ypPG2R58stAyzngNWqowIq0K2IPhpd B5Kk5YDS6QI6786oS6GD8ID/SpKOTPYlAxhDWn0wNHhram2A9+3q/R9PjO3C8XjLXuvz gD8sf6vaCcso1YKlmQi8dlxUkd+iz7SbxXMpbZ6IvGb9aHnxwmjU3NVewCfd/pU0boAG Sz+nazemNtLWHXU3UKTNCO+FDV4GU2KJmK5rptlpE9Ax3Uy84pGr/L4XkAp5cdblWpd2 Gk+g== X-Gm-Message-State: AIkVDXKgLg/ztRCCBNjInqGA6kABGXFXZziu5vHKUX19JPi9n9YSUP6frgvZZA/VtW3kQQ== X-Received: by 10.98.212.23 with SMTP id a23mr2501162pfh.94.1482361579801; Wed, 21 Dec 2016 15:06:19 -0800 (PST) From: Richard Henderson To: libc-alpha@sourceware.org Subject: [PATCH v2 14/16] arm: Add string-fza.h Date: Wed, 21 Dec 2016 15:06:03 -0800 Message-Id: <20161221230605.28638-15-rth@twiddle.net> In-Reply-To: <20161221230605.28638-1-rth@twiddle.net> References: <20161221230605.28638-1-rth@twiddle.net> While arm has the more important string functions in assembly, there are still a few generic routines used. Use the UQSUB8 insn for testing of zeros. * sysdeps/arm/armv6t2/string-fza.h: New file. --- sysdeps/arm/armv6t2/string-fza.h | 69 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 sysdeps/arm/armv6t2/string-fza.h diff --git a/sysdeps/arm/armv6t2/string-fza.h b/sysdeps/arm/armv6t2/string-fza.h new file mode 100644 index 0000000..e46abb1 --- /dev/null +++ b/sysdeps/arm/armv6t2/string-fza.h @@ -0,0 +1,69 @@ +/* string-fza.h -- zero byte detection; basics. ARM version. + Copyright (C) 2016 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#ifndef STRING_FZA_H +#define STRING_FZA_H 1 + +#include + +/* This function returns at least one bit set within every byte + of X that is zero. */ + +static inline op_t +find_zero_all (op_t x) +{ + /* Use unsigned saturated subtraction from 1 in each byte. + That leaves 1 for every byte that was zero. */ + op_t ret, ones = (op_t)-1 / 0xff; + asm ("uqsub8 %0,%1,%2" : "=r"(ret) : "r"(ones), "r"(x)); + return ret; +} + +/* Identify bytes that are equal between X1 and X2. */ + +static inline op_t +find_eq_all (op_t x1, op_t x2) +{ + return find_zero_all (x1 ^ x2); +} + +/* Identify zero bytes in X1 or equality between X1 and X2. */ + +static inline op_t +find_zero_eq_all (op_t x1, op_t x2) +{ + return find_zero_all (x1) | find_zero_all (x1 ^ x2); +} + +/* Identify zero bytes in X1 or inequality between X1 and X2. */ + +static inline op_t +find_zero_ne_all (op_t x1, op_t x2) +{ + /* Make use of the fact that we'll already have ONES in a register. */ + op_t ones = (op_t)-1 / 0xff; + return find_zero_all (x1) | (find_zero_all (x1 ^ x2) ^ ones); +} + +/* Define the "inexact" versions in terms of the exact versions. */ +#define find_zero_low find_zero_all +#define find_eq_low find_eq_all +#define find_zero_eq_low find_zero_eq_all +#define find_zero_ne_low find_zero_ne_all + +#endif /* STRING_FZA_H */