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Thu, 23 May 2019 12:59:09 +0000 (UTC) From: David Hildenbrand To: Richard Henderson , Richard Henderson References: <20190515203112.506-1-david@redhat.com> <20190515203112.506-2-david@redhat.com> <44d7ddb4-040f-6778-7439-043b94e354ec@redhat.com> <0935643f-941f-5883-c481-8ac18d57c98d@linaro.org> <1f6001a2-e1d3-2b6f-e84a-8b9963302a3c@redhat.com> <9b00d53e-d676-7d19-cab6-7fb7a6715d1e@twiddle.net> <273c1e4f-3216-78aa-508e-b063c0612854@redhat.com> <1c3a49f8-56bd-1577-60a4-7c29ca1c0d83@twiddle.net> <8ea05b5e-9d8d-f514-7336-8d7637188009@redhat.com> Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <968a70bb-c025-235f-2914-ecb4142ae79b@redhat.com> Date: Thu, 23 May 2019 14:59:08 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <8ea05b5e-9d8d-f514-7336-8d7637188009@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 23 May 2019 12:59:14 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [PATCH v1 1/5] s390x/tcg: Implement VECTOR FIND ANY ELEMENT EQUAL 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: Thomas Huth , qemu-s390x , Cornelia Huck , "qemu-devel@nongnu.org Developers" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 23.05.19 14:34, David Hildenbrand wrote: > On 23.05.19 14:27, Richard Henderson wrote: >> On 5/23/19 3:50 AM, David Hildenbrand wrote: >>> /* >>> * Returns the number of bits composing one element. >>> */ >>> static uint8_t get_element_bits(uint8_t es) >>> { >>> return (1 << es) * BITS_PER_BYTE; >>> } >>> >>> /* >>> * Returns the bitmask for a single element. >>> */ >>> static uint64_t get_single_element_mask(uint8_t es) >>> { >>> return -1ull >> (64 - get_element_bits(es)); >>> } >>> >>> /* >>> * Returns the bitmask for a single element (excluding the MSB). >>> */ >>> static uint64_t get_single_element_lsbs_mask(uint8_t es) >>> { >>> return -1ull >> (65 - get_element_bits(es)); >>> } >>> >>> /* >>> * Returns the bitmasks for multiple elements (excluding the MSBs). >>> */ >>> static uint64_t get_element_lsbs_mask(uint8_t es) >>> { >>> return dup_const(es, get_single_element_lsbs_mask(es)); >>> } >>> >>> static int vfae(void *v1, const void *v2, const void *v3, bool in, >>> bool rt, bool zs, uint8_t es) >>> { >>> const uint64_t mask = get_element_lsbs_mask(es); >>> const int bits = get_element_bits(es); >>> uint64_t a0, a1, b0, b1, e0, e1, t0, t1, z0, z1; >>> uint64_t first_zero = 16; >>> uint64_t first_equal; >>> int i; >>> >>> a0 = s390_vec_read_element64(v2, 0); >>> a1 = s390_vec_read_element64(v2, 1); >>> b0 = s390_vec_read_element64(v3, 0); >>> b1 = s390_vec_read_element64(v3, 1); >>> e0 = 0; >>> e1 = 0; >>> /* compare against equality with every other element */ >>> for (i = 0; i < 64; i += bits) { >>> t0 = i ? rol64(b0, i) : b0; >>> t1 = i ? rol64(b1, i) : b1; >>> e0 |= zero_search(a0 ^ t0, mask); >>> e0 |= zero_search(a0 ^ t1, mask); >>> e1 |= zero_search(a1 ^ t0, mask); >>> e1 |= zero_search(a1 ^ t1, mask); >>> } >> >> I don't see that this is doing what you want. You're shifting one element of B >> down, but not broadcasting it so that it is compared against every element of A. >> >> I'd expect something like >> >> t0 = dup_const(es, b0 >> i); >> t1 = dup_const(es, b1 >> i); >> >> (I also don't see what rol is getting you that shift doesn't.) > > Let's assume > > a0 = [0, 1, 2, 3] > a1 = [4, 5, 6, 7] > > b0 = [8, 8, 8, 4] > b1 = [8, 8, 8, 8] > > What I would check is > > First iteration > > a0 == [8, 8, 8, 4] -> no match > a0 == [8, 8, 8, 8] -> no match > a1 == [8, 8, 8, 4] -> no match > a1 == [8, 8, 8, 8] -> no match > > Second iteration > > a0 == [8, 8, 4, 8] -> no match > a0 == [8, 8, 8, 8] -> no match > a1 == [8, 8, 4, 8] > a1 == [8, 8, 8, 8] -> no match > > ... > > Last iteration > > a0 == [4, 8, 8, 8] -> no match > a0 == [8, 8, 8, 8] -> no match > a1 == [4, 8, 8, 8] -> match in first element > a1 == [8, 8, 8, 8] -> no match > > What am i missing? > > I guess I can simplify to t0 = rol64(b0, i); t1 = rol64(b1, i); My approach: Compare all elements of B at a time Your approach: Compare a single element of B at a time If I'm not wrong, it boils down to to whether rol64() or dup_const(es, b0 >> i) is faster ;) -- Thanks, David / dhildenb