Add android_memset16/android_memset32 for aarch64.

Included new unit tests for these functions.

Bug: 15456369

Change-Id: I3fac02f61c62d15d54d0df51957680d7155e98ae

1 files changed, 211 insertions, 0 deletions

diff --git a/libcutils/arch-arm64/android_memset.S b/libcutils/arch-arm64/android_memset.S
new file mode 100644
index 0000000..9a83a68
--- /dev/null
+++ b/libcutils/arch-arm64/android_memset.S
@@ -0,0 +1,211 @@
+/* Copyright (c) 2012, Linaro Limited
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions are met:
+       * Redistributions of source code must retain the above copyright
+         notice, this list of conditions and the following disclaimer.
+       * Redistributions in binary form must reproduce the above copyright
+         notice, this list of conditions and the following disclaimer in the
+         documentation and/or other materials provided with the distribution.
+       * Neither the name of the Linaro nor the
+         names of its contributors may be used to endorse or promote products
+         derived from this software without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* Assumptions:
+ *
+ * ARMv8-a, AArch64
+ * Unaligned accesses
+ *
+ */
+
+/* By default we assume that the DC instruction can be used to zero
+   data blocks more efficiently.  In some circumstances this might be
+   unsafe, for example in an asymmetric multiprocessor environment with
+   different DC clear lengths (neither the upper nor lower lengths are
+   safe to use). */
+
+#define dst  		x0
+#define count		x2
+#define tmp1		x3
+#define tmp1w		w3
+#define tmp2		x4
+#define tmp2w		w4
+#define zva_len_x	x5
+#define zva_len		w5
+#define zva_bits_x	x6
+
+#define A_l		x1
+#define A_lw		w1
+#define tmp3w		w9
+
+#define ENTRY(f) \
+  .text; \
+  .globl f; \
+  .align 0; \
+  .type f, %function; \
+  f: \
+  .cfi_startproc \
+
+#define END(f) \
+  .cfi_endproc; \
+  .size f, .-f; \
+
+ENTRY(android_memset16)
+	ands   A_lw, A_lw, #0xffff
+	b.eq	.Lzero_mem
+	orr	A_lw, A_lw, A_lw, lsl #16
+	b .Lexpand_to_64
+END(android_memset16)
+
+ENTRY(android_memset32)
+	cmp	    A_lw, #0
+	b.eq	.Lzero_mem
+.Lexpand_to_64:
+	orr	A_l, A_l, A_l, lsl #32
+.Ltail_maybe_long:
+	cmp	count, #64
+	b.ge	.Lnot_short
+.Ltail_maybe_tiny:
+	cmp	count, #15
+	b.le	.Ltail15tiny
+.Ltail63:
+	ands	tmp1, count, #0x30
+	b.eq	.Ltail15
+	add	dst, dst, tmp1
+	cmp	tmp1w, #0x20
+	b.eq	1f
+	b.lt	2f
+	stp	A_l, A_l, [dst, #-48]
+1:
+	stp	A_l, A_l, [dst, #-32]
+2:
+	stp	A_l, A_l, [dst, #-16]
+
+.Ltail15:
+	and	count, count, #15
+	add	dst, dst, count
+	stp	A_l, A_l, [dst, #-16]	/* Repeat some/all of last store. */
+	ret
+
+.Ltail15tiny:
+	/* Set up to 15 bytes.  Does not assume earlier memory
+	   being set.  */
+	tbz	count, #3, 1f
+	str	A_l, [dst], #8
+1:
+	tbz	count, #2, 1f
+	str	A_lw, [dst], #4
+1:
+	tbz	count, #1, 1f
+	strh	A_lw, [dst], #2
+1:
+	ret
+
+	/* Critical loop.  Start at a new cache line boundary.  Assuming
+	 * 64 bytes per line, this ensures the entire loop is in one line.  */
+	.p2align 6
+.Lnot_short:
+	neg	tmp2, dst
+	ands	tmp2, tmp2, #15
+	b.eq	2f
+	/* Bring DST to 128-bit (16-byte) alignment.  We know that there's
+	 * more than that to set, so we simply store 16 bytes and advance by
+	 * the amount required to reach alignment.  */
+	sub	count, count, tmp2
+	stp	A_l, A_l, [dst]
+	add	dst, dst, tmp2
+	/* There may be less than 63 bytes to go now.  */
+	cmp	count, #63
+	b.le	.Ltail63
+2:
+	sub	dst, dst, #16		/* Pre-bias.  */
+	sub	count, count, #64
+1:
+	stp	A_l, A_l, [dst, #16]
+	stp	A_l, A_l, [dst, #32]
+	stp	A_l, A_l, [dst, #48]
+	stp	A_l, A_l, [dst, #64]!
+	subs	count, count, #64
+	b.ge	1b
+	tst	count, #0x3f
+	add	dst, dst, #16
+	b.ne	.Ltail63
+	ret
+
+	/* For zeroing memory, check to see if we can use the ZVA feature to
+	 * zero entire 'cache' lines.  */
+.Lzero_mem:
+	mov	A_l, #0
+	cmp	count, #63
+	b.le	.Ltail_maybe_tiny
+	neg	tmp2, dst
+	ands	tmp2, tmp2, #15
+	b.eq	1f
+	sub	count, count, tmp2
+	stp	A_l, A_l, [dst]
+	add	dst, dst, tmp2
+	cmp	count, #63
+	b.le	.Ltail63
+1:
+	/* For zeroing small amounts of memory, it's not worth setting up
+	 * the line-clear code.  */
+	cmp	count, #128
+	b.lt	.Lnot_short
+	mrs	tmp1, dczid_el0
+	tbnz	tmp1, #4, .Lnot_short
+	mov	tmp3w, #4
+	and	zva_len, tmp1w, #15	/* Safety: other bits reserved.  */
+	lsl	zva_len, tmp3w, zva_len
+
+.Lzero_by_line:
+	/* Compute how far we need to go to become suitably aligned.  We're
+	 * already at quad-word alignment.  */
+	cmp	count, zva_len_x
+	b.lt	.Lnot_short		/* Not enough to reach alignment.  */
+	sub	zva_bits_x, zva_len_x, #1
+	neg	tmp2, dst
+	ands	tmp2, tmp2, zva_bits_x
+	b.eq	1f			/* Already aligned.  */
+	/* Not aligned, check that there's enough to copy after alignment.  */
+	sub	tmp1, count, tmp2
+	cmp	tmp1, #64
+	ccmp	tmp1, zva_len_x, #8, ge	/* NZCV=0b1000 */
+	b.lt	.Lnot_short
+	/* We know that there's at least 64 bytes to zero and that it's safe
+	 * to overrun by 64 bytes.  */
+	mov	count, tmp1
+2:
+	stp	A_l, A_l, [dst]
+	stp	A_l, A_l, [dst, #16]
+	stp	A_l, A_l, [dst, #32]
+	subs	tmp2, tmp2, #64
+	stp	A_l, A_l, [dst, #48]
+	add	dst, dst, #64
+	b.ge	2b
+	/* We've overrun a bit, so adjust dst downwards.  */
+	add	dst, dst, tmp2
+1:
+	sub	count, count, zva_len_x
+3:
+	dc	zva, dst
+	add	dst, dst, zva_len_x
+	subs	count, count, zva_len_x
+	b.ge	3b
+	ands	count, count, zva_bits_x
+	b.ne	.Ltail_maybe_long
+	ret
+END(android_memset32)