1 files changed, 67 insertions, 0 deletions
diff --git a/string/aarch64/experimental/strcpy-sve.S b/string/aarch64/experimental/strcpy-sve.S
new file mode 100644
index 000000000000..57b77c8a00e7
--- /dev/null
+++ b/string/aarch64/experimental/strcpy-sve.S
@@ -0,0 +1,67 @@
+/*
+ * strcpy/stpcpy - copy a string returning pointer to start/end.
+ *
+ * Copyright (c) 2018-2022, Arm Limited.
+ * SPDX-License-Identifier: MIT OR Apache-2.0 WITH LLVM-exception
+ */
+
+#include "asmdefs.h"
+
+.arch armv8-a+sve
+
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64
+ * SVE Available.
+ */
+
+/* To build as stpcpy, define BUILD_STPCPY before compiling this file.  */
+#ifdef BUILD_STPCPY
+#define FUNC  __stpcpy_aarch64_sve
+#else
+#define FUNC  __strcpy_aarch64_sve
+#endif
+
+ENTRY (FUNC)
+	setffr				/* initialize FFR */
+	ptrue	p2.b, all		/* all ones; loop invariant */
+	mov	x2, 0			/* initialize offset */
+
+	.p2align 4
+	/* Read a vector's worth of bytes, stopping on first fault.  */
+0:	ldff1b	z0.b, p2/z, [x1, x2]
+	rdffrs	p0.b, p2/z
+	b.nlast	1f
+
+	/* First fault did not fail: the whole vector is valid.
+	   Avoid depending on the contexts of FFR beyond the branch.  */
+	cmpeq	p1.b, p2/z, z0.b, 0	/* search for zeros */
+	b.any	2f
+
+	/* No zero found.  Store the whole vector and loop.  */
+	st1b	z0.b, p2, [x0, x2]
+	incb	x2, all
+	b	0b
+
+	/* First fault failed: only some of the vector is valid.
+	   Perform the comparison only on the valid bytes.  */
+1:	cmpeq	p1.b, p0/z, z0.b, 0	/* search for zeros */
+	b.any	2f
+
+	/* No zero found.  Store the valid portion of the vector and loop.  */
+	setffr				/* re-init FFR */
+	st1b	z0.b, p0, [x0, x2]
+	incp	x2, p0.b
+	b	0b
+
+	/* Zero found.  Crop the vector to the found zero and finish.  */
+2:	brka	p0.b, p2/z, p1.b
+	st1b	z0.b, p0, [x0, x2]
+#ifdef BUILD_STPCPY
+	add	x0, x0, x2
+	sub	x0, x0, 1
+	incp	x0, p0.b
+#endif
+	ret
+
+END (FUNC)