From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1791) id 9F7EA38493CB; Fri, 13 Jan 2023 20:03:45 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9F7EA38493CB DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1673640225; bh=qYImyGSMEJVniwB4VmY+gAco2noWpMWwQlyfXZTYE3s=; h=From:To:Subject:Date:From; b=WwJZblpyfHFrnYh08XYnUlA8NXYkp4GPjATGZG1prBtLTABP4cIK61XNIwk2r+XhQ JSG27LMjC4PVDiWuhnCNAXdHiBQcNJHB067BONLy85XHazVskAWF/yaeXTBTBpA6lT hVx8eX8P7Q2RwRMmVIVoxSNcwQYkq0ztGU3tF6jI= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Adhemerval Zanella To: glibc-cvs@sourceware.org Subject: [glibc/azanella/generic-strings] arm: Add string-fza.h X-Act-Checkin: glibc X-Git-Author: Richard Henderson X-Git-Refname: refs/heads/azanella/generic-strings X-Git-Oldrev: 27c71d8cfcfb331e9625cbd2047d8da1c8c3009b X-Git-Newrev: 9d18a422008a8d292bd12ad0fe7b1796a8c4cb03 Message-Id: <20230113200345.9F7EA38493CB@sourceware.org> Date: Fri, 13 Jan 2023 20:03:45 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9d18a422008a8d292bd12ad0fe7b1796a8c4cb03 commit 9d18a422008a8d292bd12ad0fe7b1796a8c4cb03 Author: Richard Henderson Date: Tue Jan 10 18:01:04 2023 -0300 arm: Add string-fza.h 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. Checked on armv7-linux-gnueabihf Diff: --- sysdeps/arm/armv6t2/string-fza.h | 92 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/sysdeps/arm/armv6t2/string-fza.h b/sysdeps/arm/armv6t2/string-fza.h new file mode 100644 index 0000000000..46a49d8a40 --- /dev/null +++ b/sysdeps/arm/armv6t2/string-fza.h @@ -0,0 +1,92 @@ +/* Zero byte detection; basics. ARM version. + Copyright (C) 2023 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 +#include +#include +#include + +/* The functions return a byte mask. */ +typedef op_t find_t; + +/* Return the mask WORD shifted based on S_INT address value, to ignore + values not presented in the aligned word read. */ +static __always_inline find_t +shift_find (find_t word, uintptr_t s) +{ + if (__BYTE_ORDER == __LITTLE_ENDIAN) + return word >> (CHAR_BIT * (s % sizeof (op_t))); + else + return word << (CHAR_BIT * (s % sizeof (op_t))); +} + +/* Mask off the bits defined the the S alignment value. */ +static __always_inline find_t +shift_find_last (find_t word, uintptr_t s) +{ + return word & create_mask (s); +} + +/* This function returns at least one bit set within every byte + of X that is zero. */ + +static __always_inline find_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 ones = repeat_bytes (0x01); + return __builtin_arm_uqsub8 (ones, x); +} + +/* Identify bytes that are equal between X1 and X2. */ + +static __always_inline find_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 __always_inline find_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 __always_inline find_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 = repeat_bytes (0x01); + 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 */