[PATCH v5 01/18] riscv: Add RVV memccpy for multiarch and non-multiarch
Yao Zihong
zihong.plct@isrc.iscas.ac.cn
Tue Feb 3 15:05:25 GMT 2026
Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn>
---
sysdeps/riscv/multiarch/memccpy-generic.c | 26 +++++++
sysdeps/riscv/multiarch/memccpy-vector.S | 24 +++++++
sysdeps/riscv/rvv/memccpy.S | 67 +++++++++++++++++++
.../unix/sysv/linux/riscv/multiarch/Makefile | 3 +
.../linux/riscv/multiarch/ifunc-impl-list.c | 5 ++
.../unix/sysv/linux/riscv/multiarch/memccpy.c | 58 ++++++++++++++++
6 files changed, 183 insertions(+)
create mode 100644 sysdeps/riscv/multiarch/memccpy-generic.c
create mode 100644 sysdeps/riscv/multiarch/memccpy-vector.S
create mode 100644 sysdeps/riscv/rvv/memccpy.S
create mode 100644 sysdeps/unix/sysv/linux/riscv/multiarch/memccpy.c
diff --git a/sysdeps/riscv/multiarch/memccpy-generic.c b/sysdeps/riscv/multiarch/memccpy-generic.c
new file mode 100644
index 0000000000..d7e6e2d847
--- /dev/null
+++ b/sysdeps/riscv/multiarch/memccpy-generic.c
@@ -0,0 +1,26 @@
+/* Re-include the default memccpy implementation.
+ Copyright (C) 2026 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/>. */
+
+#include <string.h>
+
+#if IS_IN(libc)
+# define MEMCCPY __memccpy_generic
+# undef weak_alias
+# define weak_alias(x, x2)
+# include <string/memccpy.c>
+#endif
diff --git a/sysdeps/riscv/multiarch/memccpy-vector.S b/sysdeps/riscv/multiarch/memccpy-vector.S
new file mode 100644
index 0000000000..8ea121e444
--- /dev/null
+++ b/sysdeps/riscv/multiarch/memccpy-vector.S
@@ -0,0 +1,24 @@
+/* Re-include the RISC-V RVV based memccpy implementation.
+ Copyright (C) 2026 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)
+# define MEMCCPY __memccpy_vector
+# undef weak_alias
+# define weak_alias(name, alias)
+# include <sysdeps/riscv/rvv/memccpy.S>
+#endif
diff --git a/sysdeps/riscv/rvv/memccpy.S b/sysdeps/riscv/rvv/memccpy.S
new file mode 100644
index 0000000000..5854d463c2
--- /dev/null
+++ b/sysdeps/riscv/rvv/memccpy.S
@@ -0,0 +1,67 @@
+/* RISC-V RVV based memccpy.
+ Copyright (C) 2026 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/>. */
+
+#include <sysdep.h>
+#include <sys/asm.h>
+
+#ifndef MEMCCPY
+# define MEMCCPY __memccpy
+#endif
+
+#define dst a0
+#define src a1
+#define c_val a2
+#define num a3
+
+#define ivl a4
+#define dst_ptr a5
+#define vfirst_idx a6
+
+#define ELEM_LMUL_SETTING m8
+#define vdata v0
+#define vmask v8
+
+ENTRY (MEMCCPY)
+.option push
+.option arch, +v
+ mv dst_ptr, dst
+L(loop):
+ vsetvli zero, num, e8, ELEM_LMUL_SETTING, ta, ma
+ vle8ff.v vdata, (src)
+
+ vmseq.vx vmask, vdata, c_val
+ vfirst.m vfirst_idx, vmask
+ csrr ivl, vl
+ bgez vfirst_idx, L(found)
+ vse8.v vdata, (dst_ptr)
+
+ sub num, num, ivl
+ add src, src, ivl
+ add dst_ptr, dst_ptr, ivl
+ bnez num, L(loop)
+ mv a0, zero
+ ret
+L(found):
+ addi vfirst_idx, vfirst_idx, 1
+ vsetvli zero, vfirst_idx, e8, ELEM_LMUL_SETTING, ta, ma
+ vse8.v vdata, (dst_ptr)
+ add a0, dst_ptr, vfirst_idx
+ ret
+.option pop
+END (MEMCCPY)
+weak_alias (MEMCCPY, memccpy)
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
index 1d26966ded..0c1c2b4467 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/Makefile
@@ -1,5 +1,8 @@
ifeq ($(subdir),string)
sysdep_routines += \
+ memccpy \
+ memccpy-generic \
+ memccpy-vector \
memcpy \
memcpy-generic \
memcpy_noalignment \
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
index a3b5731411..cd9460f57e 100644
--- a/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/ifunc-impl-list.c
@@ -53,5 +53,10 @@ __libc_ifunc_impl_list (const char *name, struct libc_ifunc_impl *array,
__memset_vector)
IFUNC_IMPL_ADD (array, i, memset, 1, __memset_generic))
+ IFUNC_IMPL (i, name, memccpy,
+ IFUNC_IMPL_ADD (array, i, memccpy, rvv_enabled,
+ __memccpy_vector)
+ IFUNC_IMPL_ADD (array, i, memccpy, 1, __memccpy_generic))
+
return 0;
}
diff --git a/sysdeps/unix/sysv/linux/riscv/multiarch/memccpy.c b/sysdeps/unix/sysv/linux/riscv/multiarch/memccpy.c
new file mode 100644
index 0000000000..84d300b3cc
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/riscv/multiarch/memccpy.c
@@ -0,0 +1,58 @@
+/* Multiple versions of memccpy.
+ All versions must be listed in ifunc-impl-list.c.
+ Copyright (C) 2026 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 memccpy so that the compiler won't complain about the type
+ mismatch with the IFUNC selector in strong_alias, below. */
+# undef memccpy
+# define memccpy __redirect_memccpy
+# include <stdint.h>
+# include <string.h>
+# include <ifunc-init.h>
+# include <riscv-ifunc.h>
+# include <sys/hwprobe.h>
+
+extern __typeof (__redirect_memccpy) __libc_memccpy;
+
+extern __typeof (__redirect_memccpy) __memccpy_generic attribute_hidden;
+extern __typeof (__redirect_memccpy) __memccpy_vector attribute_hidden;
+
+static inline __typeof (__redirect_memccpy) *
+select_memccpy_ifunc (uint64_t dl_hwcap, __riscv_hwprobe_t hwprobe_func)
+{
+ unsigned long long v;
+
+ if (__riscv_hwprobe_one (hwprobe_func, RISCV_HWPROBE_KEY_IMA_EXT_0, &v) == 0
+ && (v & RISCV_HWPROBE_IMA_V) == RISCV_HWPROBE_IMA_V)
+ return __memccpy_vector;
+
+ return __memccpy_generic;
+}
+
+riscv_libc_ifunc (__libc_memccpy, select_memccpy_ifunc);
+
+# undef memccpy
+weak_alias (__libc_memccpy, memccpy);
+# ifdef SHARED
+__hidden_ver1 (memccpy, __GI_memccpy, __redirect_memccpy)
+ __attribute__ ((visibility ("hidden"))) __attribute_copy__ (memccpy);
+# endif
+#else
+# include <string/memccpy.c>
+#endif
--
2.47.3
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