[PATCH 1/6] riscv: add vectorized memccpy

[Pincheng Wang]

The vector implementation uses m8 register grouping and processes data in
vector-length chunks, providing significant performance improvements on
RVV-capable hardware.  Use conditional compilation to fall back to the
generic implementation when __riscv_vector is not available, maintaining
compatibility with non-vector RISC-V systems.

Signed-off-by: Pincheng Wang <pincheng.plct@isrc.iscas.ac.cn>
---
 newlib/libc/machine/riscv/Makefile.inc  | 18 ++++++++++--
 newlib/libc/machine/riscv/memccpy-asm.S | 39 +++++++++++++++++++++++++
 newlib/libc/machine/riscv/memccpy.c     |  5 ++++
 3 files changed, 60 insertions(+), 2 deletions(-)
 create mode 100644 newlib/libc/machine/riscv/memccpy-asm.S
 create mode 100644 newlib/libc/machine/riscv/memccpy.c

diff --git a/newlib/libc/machine/riscv/Makefile.inc b/newlib/libc/machine/riscv/Makefile.inc
index 3cc6e198f..676608aa5 100644
--- a/newlib/libc/machine/riscv/Makefile.inc
+++ b/newlib/libc/machine/riscv/Makefile.inc
@@ -1,3 +1,17 @@
 libc_a_SOURCES += \
-	%D%/memmove-asm.S %D%/memmove.c %D%/memset.S %D%/memcpy-asm.S %D%/memcpy.c %D%/strlen.c \
-	%D%/strcpy.c %D%/stpcpy.c %D%/strcmp.S %D%/memchr.c %D%/memrchr.c %D%/setjmp.S %D%/ieeefp.c %D%/ffs.c
+        %D%/ffs.c \
+        %D%/ieeefp.c \
+        %D%/memccpy-asm.S \
+        %D%/memccpy.c \
+        %D%/memchr.c \
+        %D%/memcpy-asm.S \
+        %D%/memcpy.c \
+        %D%/memmove-asm.S \
+        %D%/memmove.c \
+        %D%/memrchr.c \
+        %D%/memset.S \
+        %D%/setjmp.S \
+        %D%/stpcpy.c \
+        %D%/strcmp.S \
+        %D%/strcpy.c \
+        %D%/strlen.c
diff --git a/newlib/libc/machine/riscv/memccpy-asm.S b/newlib/libc/machine/riscv/memccpy-asm.S
new file mode 100644
index 000000000..3c33a8ae0
--- /dev/null
+++ b/newlib/libc/machine/riscv/memccpy-asm.S
@@ -0,0 +1,39 @@
+#if defined(__riscv_vector) && !defined(__OPTIMIZE_SIZE__) && !defined(PREFER_SIZE_OVER_SPEED)
+.text
+.option push
+.option arch, +zve32x
+.global memccpy
+.type memccpy, @function
+memccpy:
+#if __riscv_landing_pad
+  lpad 0
+#endif
+  beqz a3, .Lnot_found
+  andi a2, a2, 0xff
+  mv a5, a0
+.Lloop:
+  vsetvli zero, a3, e8, m8, ta, ma
+  vle8ff.v v0, (a1)
+
+  vmseq.vx v8, v0, a2
+  vfirst.m a6, v8
+  csrr a4, vl
+  bgez a6, .Lfound
+  vse8.v v0, (a5)
+
+  sub a3, a3, a4
+  add a1, a1, a4
+  add a5, a5, a4
+  bnez a3, .Lloop
+.Lnot_found:
+  mv a0, zero
+  ret
+.Lfound:
+  addi a6, a6, 1
+  vsetvli zero, a6, e8, m8, ta, ma
+  vse8.v v0, (a5)
+  add a0, a5, a6
+  ret
+.size memccpy, .-memccpy
+.option pop
+#endif
diff --git a/newlib/libc/machine/riscv/memccpy.c b/newlib/libc/machine/riscv/memccpy.c
new file mode 100644
index 000000000..7ca779d48
--- /dev/null
+++ b/newlib/libc/machine/riscv/memccpy.c
@@ -0,0 +1,5 @@
+#if defined(__OPTIMIZE_SIZE__) || defined(PREFER_SIZE_OVER_SPEED) || !defined(__riscv_vector)
+# include "../../string/memccpy.c"
+#else
+/* memccpy defined in memccpy-asm.S */
+#endif
-- 
2.39.5