ARCv2: optimised string routines

Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

1 files changed, 236 insertions, 0 deletions

diff --git a/libc/string/arc/arcv2/memcpy.S b/libc/string/arc/arcv2/memcpy.S
new file mode 100644
index 000000000..7573daf51
--- /dev/null
+++ b/libc/string/arc/arcv2/memcpy.S
@@ -0,0 +1,236 @@
+/*
+ * Copyright (C) 2014-15 Synopsys, Inc. (www.synopsys.com)
+ *
+ * Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
+ */
+
+#include <features.h>
+#include <sysdep.h>
+
+#ifdef __LITTLE_ENDIAN__
+# define SHIFT_1(RX,RY,IMM)	asl	RX, RY, IMM	; <<
+# define SHIFT_2(RX,RY,IMM)	lsr	RX, RY, IMM	; >>
+# define MERGE_1(RX,RY,IMM)	asl	RX, RY, IMM
+# define MERGE_2(RX,RY,IMM)
+# define EXTRACT_1(RX,RY,IMM)	and	RX, RY, 0xFFFF
+# define EXTRACT_2(RX,RY,IMM)	lsr	RX, RY, IMM
+#else
+# define SHIFT_1(RX,RY,IMM)	lsr	RX, RY, IMM	; >>
+# define SHIFT_2(RX,RY,IMM)	asl	RX, RY, IMM	; <<
+# define MERGE_1(RX,RY,IMM)	asl	RX, RY, IMM	; <<
+# define MERGE_2(RX,RY,IMM)	asl	RX, RY, IMM	; <<
+# define EXTRACT_1(RX,RY,IMM)	lsr	RX, RY, IMM
+# define EXTRACT_2(RX,RY,IMM)	lsr	RX, RY, 0x08
+#endif
+
+#ifdef __LL64__
+# define PREFETCH_READ(RX)	prefetch [RX, 56]
+# define PREFETCH_WRITE(RX)	prefetchw [RX, 64]
+# define LOADX(DST,RX)		ldd.ab	DST, [RX, 8]
+# define STOREX(SRC,RX)		std.ab	SRC, [RX, 8]
+# define ZOLSHFT		5
+# define ZOLAND			0x1F
+#else
+# define PREFETCH_READ(RX)	prefetch [RX, 28]
+# define PREFETCH_WRITE(RX)	prefetchw [RX, 32]
+# define LOADX(DST,RX)		ld.ab	DST, [RX, 4]
+# define STOREX(SRC,RX)		st.ab	SRC, [RX, 4]
+# define ZOLSHFT		4
+# define ZOLAND			0xF
+#endif
+
+ENTRY(memcpy)
+	prefetch  [r1]		; Prefetch the read location
+	prefetchw [r0]		; Prefetch the write location
+	mov.f	0, r2
+;;; if size is zero
+	jz.d	[blink]
+	mov	r3, r0		; don't clobber ret val
+
+;;; if size <= 8
+	cmp	r2, 8
+	bls.d	@.Lsmallchunk
+	mov.f	lp_count, r2
+
+	and.f	r4, r0, 0x03
+	rsub	lp_count, r4, 4
+	lpnz	@.Laligndestination
+	;; LOOP BEGIN
+	ldb.ab	r5, [r1,1]
+	sub	r2, r2, 1
+	stb.ab	r5, [r3,1]
+.Laligndestination:
+
+;;; Check the alignment of the source
+	and.f	r4, r1, 0x03
+	bnz.d	@.Lsourceunaligned
+
+;;; CASE 0: Both source and destination are 32bit aligned
+;;; Convert len to Dwords, unfold x4
+	lsr.f	lp_count, r2, ZOLSHFT
+	lpnz	@.Lcopy32_64bytes
+	;; LOOP START
+	LOADX (r6, r1)
+	PREFETCH_READ (r1)
+	PREFETCH_WRITE (r3)
+	LOADX (r8, r1)
+	LOADX (r10, r1)
+	LOADX (r4, r1)
+	STOREX (r6, r3)
+	STOREX (r8, r3)
+	STOREX (r10, r3)
+	STOREX (r4, r3)
+.Lcopy32_64bytes:
+
+	and.f	lp_count, r2, ZOLAND ;Last remaining 31 bytes
+.Lsmallchunk:
+	lpnz	@.Lcopyremainingbytes
+	;; LOOP START
+	ldb.ab	r5, [r1,1]
+	stb.ab	r5, [r3,1]
+.Lcopyremainingbytes:
+
+	j	[blink]
+;;; END CASE 0
+
+.Lsourceunaligned:
+	cmp	r4, 2
+	beq.d	@.LunalignedOffby2
+	sub	r2, r2, 1
+
+	bhi.d	@.LunalignedOffby3
+	ldb.ab	r5, [r1, 1]
+
+;;; CASE 1: The source is unaligned, off by 1
+	;; Hence I need to read 1 byte for a 16bit alignment
+	;; and 2bytes to reach 32bit alignment
+	ldh.ab	r6, [r1, 2]
+	sub	r2, r2, 2
+	;; Convert to words, unfold x2
+	lsr.f	lp_count, r2, 3
+	MERGE_1 (r6, r6, 8)
+	MERGE_2 (r5, r5, 24)
+	or	r5, r5, r6
+
+	;; Both src and dst are aligned
+	lpnz	@.Lcopy8bytes_1
+	;; LOOP START
+	ld.ab	r6, [r1, 4]
+	prefetch [r1, 28]	;Prefetch the next read location
+	ld.ab	r8, [r1,4]
+	prefetchw [r3, 32]	;Prefetch the next write location
+
+	SHIFT_1	(r7, r6, 24)
+	or	r7, r7, r5
+	SHIFT_2	(r5, r6, 8)
+
+	SHIFT_1	(r9, r8, 24)
+	or	r9, r9, r5
+	SHIFT_2	(r5, r8, 8)
+
+	st.ab	r7, [r3, 4]
+	st.ab	r9, [r3, 4]
+.Lcopy8bytes_1:
+
+	;; Write back the remaining 16bits
+	EXTRACT_1 (r6, r5, 16)
+	sth.ab	r6, [r3, 2]
+	;; Write back the remaining 8bits
+	EXTRACT_2 (r5, r5, 16)
+	stb.ab	r5, [r3, 1]
+
+	and.f	lp_count, r2, 0x07 ;Last 8bytes
+	lpnz	@.Lcopybytewise_1
+	;; LOOP START
+	ldb.ab	r6, [r1,1]
+	stb.ab	r6, [r3,1]
+.Lcopybytewise_1:
+	j	[blink]
+
+.LunalignedOffby2:
+;;; CASE 2: The source is unaligned, off by 2
+	ldh.ab	r5, [r1, 2]
+	sub	r2, r2, 1
+
+	;; Both src and dst are aligned
+	;; Convert to words, unfold x2
+	lsr.f	lp_count, r2, 3
+#ifdef __BIG_ENDIAN__
+	asl.nz	r5, r5, 16
+#endif
+	lpnz	@.Lcopy8bytes_2
+	;; LOOP START
+	ld.ab	r6, [r1, 4]
+	prefetch [r1, 28]	;Prefetch the next read location
+	ld.ab	r8, [r1,4]
+	prefetchw [r3, 32]	;Prefetch the next write location
+
+	SHIFT_1	(r7, r6, 16)
+	or	r7, r7, r5
+	SHIFT_2	(r5, r6, 16)
+
+	SHIFT_1	(r9, r8, 16)
+	or	r9, r9, r5
+	SHIFT_2	(r5, r8, 16)
+
+	st.ab	r7, [r3, 4]
+	st.ab	r9, [r3, 4]
+.Lcopy8bytes_2:
+
+#ifdef __BIG_ENDIAN__
+	lsr.nz	r5, r5, 16
+#endif
+	sth.ab	r5, [r3, 2]
+
+	and.f	lp_count, r2, 0x07 ;Last 8bytes
+	lpnz	@.Lcopybytewise_2
+	;; LOOP START
+	ldb.ab	r6, [r1,1]
+	stb.ab	r6, [r3,1]
+.Lcopybytewise_2:
+	j	[blink]
+
+.LunalignedOffby3:
+;;; CASE 3: The source is unaligned, off by 3
+;;; Hence, I need to read 1byte for achieve the 32bit alignment
+
+	;; Both src and dst are aligned
+	;; Convert to words, unfold x2
+	lsr.f	lp_count, r2, 3
+#ifdef __BIG_ENDIAN__
+	asl.ne	r5, r5, 24
+#endif
+	lpnz	@.Lcopy8bytes_3
+	;; LOOP START
+	ld.ab	r6, [r1, 4]
+	prefetch [r1, 28]	;Prefetch the next read location
+	ld.ab	r8, [r1,4]
+	prefetchw [r3, 32]	;Prefetch the next write location
+
+	SHIFT_1	(r7, r6, 8)
+	or	r7, r7, r5
+	SHIFT_2	(r5, r6, 24)
+
+	SHIFT_1	(r9, r8, 8)
+	or	r9, r9, r5
+	SHIFT_2	(r5, r8, 24)
+
+	st.ab	r7, [r3, 4]
+	st.ab	r9, [r3, 4]
+.Lcopy8bytes_3:
+
+#ifdef __BIG_ENDIAN__
+	lsr.nz	r5, r5, 24
+#endif
+	stb.ab	r5, [r3, 1]
+
+	and.f	lp_count, r2, 0x07 ;Last 8bytes
+	lpnz	@.Lcopybytewise_3
+	;; LOOP START
+	ldb.ab	r6, [r1,1]
+	stb.ab	r6, [r3,1]
+.Lcopybytewise_3:
+	j	[blink]
+
+END(memcpy)
+libc_hidden_def(memcpy)