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author | Evan Green <evan@rivosinc.com> | 2024-02-27 14:56:43 -0800 |
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committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-03-01 07:15:01 -0800 |
commit | 587a1290a1af7bee6dbb40ebadb7a4d71e698baf (patch) | |
tree | 1e01dbbb28f39cc0c24653f56d9482038fa25339 /sysdeps/riscv/memcpy.c | |
parent | a2b47f7d4679a01d56827e1aff2a40de173fab23 (diff) | |
download | glibc-587a1290a1af7bee6dbb40ebadb7a4d71e698baf.tar.gz glibc-587a1290a1af7bee6dbb40ebadb7a4d71e698baf.tar.xz glibc-587a1290a1af7bee6dbb40ebadb7a4d71e698baf.zip |
riscv: Add and use alignment-ignorant memcpy
For CPU implementations that can perform unaligned accesses with little or no performance penalty, create a memcpy implementation that does not bother aligning buffers. It will use a block of integer registers, a single integer register, and fall back to bytewise copy for the remainder. Signed-off-by: Evan Green <evan@rivosinc.com> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'sysdeps/riscv/memcpy.c')
-rw-r--r-- | sysdeps/riscv/memcpy.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/sysdeps/riscv/memcpy.c b/sysdeps/riscv/memcpy.c new file mode 100644 index 0000000000..20f9548c44 --- /dev/null +++ b/sysdeps/riscv/memcpy.c @@ -0,0 +1,63 @@ +/* Multiple versions of memcpy. + All versions must be listed in ifunc-impl-list.c. + Copyright (C) 2017-2024 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 + <https://www.gnu.org/licenses/>. */ + +#if IS_IN (libc) +/* Redefine memcpy so that the compiler won't complain about the type + mismatch with the IFUNC selector in strong_alias, below. */ +# undef memcpy +# define memcpy __redirect_memcpy +# include <stdint.h> +# include <string.h> +# include <ifunc-init.h> +# include <riscv-ifunc.h> +# include <sys/hwprobe.h> + +# define INIT_ARCH() + +extern __typeof (__redirect_memcpy) __libc_memcpy; + +extern __typeof (__redirect_memcpy) __memcpy_generic attribute_hidden; +extern __typeof (__redirect_memcpy) __memcpy_noalignment attribute_hidden; + +static inline __typeof (__redirect_memcpy) * +select_memcpy_ifunc (uint64_t dl_hwcap, __riscv_hwprobe_t hwprobe_func) +{ + unsigned long long int value; + + INIT_ARCH (); + + if (__riscv_hwprobe_one (hwprobe_func, RISCV_HWPROBE_KEY_CPUPERF_0, &value) != 0) + return __memcpy_generic; + + if ((value & RISCV_HWPROBE_MISALIGNED_MASK) == RISCV_HWPROBE_MISALIGNED_FAST) + return __memcpy_noalignment; + + return __memcpy_generic; +} + +riscv_libc_ifunc (__libc_memcpy, select_memcpy_ifunc); + +# undef memcpy +strong_alias (__libc_memcpy, memcpy); +# ifdef SHARED +__hidden_ver1 (memcpy, __GI_memcpy, __redirect_memcpy) + __attribute__ ((visibility ("hidden"))) __attribute_copy__ (memcpy); +# endif + +#endif |