From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-x22a.google.com (mail-oi1-x22a.google.com [IPv6:2607:f8b0:4864:20::22a]) by sourceware.org (Postfix) with ESMTPS id B3AC23858D1E for ; Mon, 9 Jan 2023 18:51:42 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org B3AC23858D1E Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=linaro.org Received: by mail-oi1-x22a.google.com with SMTP id d127so7932730oif.12 for ; Mon, 09 Jan 2023 10:51:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:from:to:cc:subject:date:message-id:reply-to; bh=Vb9Xc9aPj5fWPzlVWrqUy0QWL+p4CIGj3ZtQstgjsM8=; b=Fn2HyjHmINyFcFG7fxaEF2mFa/0hbzTNH+Ww2emxCx4rBJZYBshrv6Vsbtfm1MYtWO QAWq5HefPy91YACw9p+y+IlfIQSsXdlvxCzDKG4d0qwXrID0SO6Y1/InkAWBdiUXVgO3 cmEHPov/AaXXUvHWbB8rWrEDUXwt8LzJTT6dWvNsHgKP0ztVNOPfiCA1nzheg1febNQT nQ8QkWihKUsngFeWVrMPZAMteABMgJqVu4oAzmV8eFKc60O+T3DvCBahYpDr4VFR0f5t HnvySF/94rjFpAudqHUJapxnTp9dZwxFA1VQqNoGbvqL1iC3D5CsptgCSgiX/pPyplPg 4TBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:organization:from:references :cc:to:content-language:subject:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Vb9Xc9aPj5fWPzlVWrqUy0QWL+p4CIGj3ZtQstgjsM8=; b=WKvhD3AR5tZsR29SYeRccHT6IAwAyViMun4YtggB4K0Z9dD5hhBfFqbGg02yoIusmW EgZWNoyfxmRUO9J7OMHcFo+ZvuX/w99cSgP4d6Lh4CS0eC/xxBLo6454HYhiXIGMzjkq r6P3Fp+G/2Mzfu8wjK23R7zBlRzB5o9I1ZEpOUD669DrdBSafdXrt8MHKgxeZ3ZpJUGv BP6Hzifx4Z6ti/StfwJ2q2vn86LxEEK+QJfR3vAsqApgU7cMBXrRQrCwRgv/GkAKK9h7 kGm5e1ONECYCZ4RH8Om3dCIlcmFSEXEsHzHHzTZpLR/8csF/vhHzE5DCyqjGrDcksXZt nxZw== X-Gm-Message-State: AFqh2koK3HVPbKeoxorKJKl9fnbucTWgozYVgGZzeNR6m1ZycVVlsU7l CMh4DGXEwA85SFwLv1c9OGy78iXGHDUBJtlUKNA= X-Google-Smtp-Source: AMrXdXuJcR8G33LKHrjqE1e9Wp+3znafrQufF5Zvff3kS/HzrRATaEOUT+1H0l8yFiooH52up6OteA== X-Received: by 2002:aca:c246:0:b0:35e:2dc2:ca78 with SMTP id s67-20020acac246000000b0035e2dc2ca78mr26275280oif.57.1673290301919; Mon, 09 Jan 2023 10:51:41 -0800 (PST) Received: from ?IPV6:2804:1b3:a7c0:a93a:9d68:9321:503b:c278? ([2804:1b3:a7c0:a93a:9d68:9321:503b:c278]) by smtp.gmail.com with ESMTPSA id bd25-20020a056808221900b0035e7d07bf9dsm4215543oib.16.2023.01.09.10.51.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Jan 2023 10:51:41 -0800 (PST) Message-ID: Date: Mon, 9 Jan 2023 15:51:38 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v5 04/17] Add string vectorized find and detection functions Content-Language: en-US To: Noah Goldstein Cc: libc-alpha@sourceware.org, Richard Henderson References: <20220919195920.956393-1-adhemerval.zanella@linaro.org> <20220919195920.956393-5-adhemerval.zanella@linaro.org> From: Adhemerval Zanella Netto Organization: Linaro In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-6.3 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_PASS,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 05/01/23 19:53, Noah Goldstein wrote: > On Mon, Sep 19, 2022 at 1:02 PM Adhemerval Zanella via Libc-alpha > wrote: >> +/* This function returns at least one bit set within every byte of X that >> + is zero. The result is exact in that, unlike find_zero_low, all bytes >> + are determinate. This is usually used for finding the index of the >> + most significant byte that was zero. */ >> +static inline op_t >> +find_zero_all (op_t x) >> +{ >> + /* For each byte, find not-zero by >> + (0) And 0x7f so that we cannot carry between bytes, >> + (1) Add 0x7f so that non-zero carries into 0x80, >> + (2) Or in the original byte (which might have had 0x80 set). >> + Then invert and mask such that 0x80 is set iff that byte was zero. */ >> + op_t m = ((op_t)-1 / 0xff) * 0x7f; > > Use repeat_byte here? Ack.