mirror of
https://github.com/Fennix-Project/Kernel.git
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123 lines
2.5 KiB
C++
123 lines
2.5 KiB
C++
/*
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This file is part of Fennix Kernel.
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Fennix Kernel is free software: you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation, either version 3 of
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the License, or (at your option) any later version.
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Fennix Kernel is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
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*/
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#include <convert.h>
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#include <memory.hpp>
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#include <limits.h>
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#include <debug.h>
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#include <cpu.hpp>
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/*
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TODO: Replace these functions with even more optimized versions.
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The current versions are fast but not as fast as they could be and also we need implementation for avx, not only sse.
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*/
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long unsigned __strlen(const char s[])
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{
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size_t ret = (size_t)s;
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asmv("._strlenLoop:"
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"cmpb $0, 0(%1)\n"
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"jz ._strlenExit\n"
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"cmpb $0, 1(%1)\n"
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"jz .scmp1\n"
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"cmpb $0, 2(%1)\n"
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"jz .scmp2\n"
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"cmpb $0, 3(%1)\n"
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"jz .scmp3\n"
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"cmpb $0, 4(%1)\n"
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"jz .scmp4\n"
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"cmpb $0, 5(%1)\n"
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"jz .scmp5\n"
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"cmpb $0, 6(%1)\n"
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"jz .scmp6\n"
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"cmpb $0, 7(%1)\n"
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"jz .scmp7\n"
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"add $8, %1\n"
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"jmp ._strlenLoop\n"
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".scmp1:"
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"inc %1\n"
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"jmp ._strlenExit\n"
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".scmp2:"
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"add $2, %1\n"
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"jmp ._strlenExit\n"
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".scmp3:"
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"add $3, %1\n"
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"jmp ._strlenExit\n"
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".scmp4:"
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"add $4, %1\n"
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"jmp ._strlenExit\n"
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".scmp5:"
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"add $5, %1\n"
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"jmp ._strlenExit\n"
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".scmp6:"
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"add $6, %1\n"
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"jmp ._strlenExit\n"
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".scmp7:"
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"add $7, %1\n"
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"._strlenExit:"
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"mov %1, %0\n"
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: "=r"(ret) : "0"(ret));
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return ret - (size_t)s;
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}
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long unsigned strlen_sse(const char s[])
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{
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return __strlen(s);
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}
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long unsigned strlen_sse2(const char s[])
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{
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return __strlen(s);
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}
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long unsigned strlen_sse3(const char s[])
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{
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return __strlen(s);
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}
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long unsigned strlen_ssse3(const char s[])
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{
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return __strlen(s);
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}
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long unsigned strlen_sse4_1(const char s[])
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{
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return __strlen(s);
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}
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long unsigned strlen_sse4_2(const char s[])
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{
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size_t ret;
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asmv("mov $-16, %0\n"
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"pxor %%xmm0, %%xmm0\n"
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".strlen42Loop:"
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"add $16, %0\n"
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"pcmpistri $0x08, (%0,%1), %%xmm0\n"
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"jnz .strlen42Loop\n"
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"add %2, %0\n"
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: "=a"(ret)
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: "d"((size_t)s), "c"((size_t)s));
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return ret;
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}
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