ARC: String library
Hand optimised asm code for ARC700 pipeline.
Originally written/optimized by Joern Rennecke
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Joern Rennecke <joern.rennecke@embecosm.com>
diff --git a/arch/arc/lib/strcpy-700.S b/arch/arc/lib/strcpy-700.S
new file mode 100644
index 0000000..b7ca4ae
--- /dev/null
+++ b/arch/arc/lib/strcpy-700.S
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/* If dst and src are 4 byte aligned, copy 8 bytes at a time.
+ If the src is 4, but not 8 byte aligned, we first read 4 bytes to get
+ it 8 byte aligned. Thus, we can do a little read-ahead, without
+ dereferencing a cache line that we should not touch.
+ Note that short and long instructions have been scheduled to avoid
+ branch stalls.
+ The beq_s to r3z could be made unaligned & long to avoid a stall
+ there, but the it is not likely to be taken often, and it
+ would also be likey to cost an unaligned mispredict at the next call. */
+
+#include <asm/linkage.h>
+
+ARC_ENTRY strcpy
+ or r2,r0,r1
+ bmsk_s r2,r2,1
+ brne.d r2,0,charloop
+ mov_s r10,r0
+ ld_s r3,[r1,0]
+ mov r8,0x01010101
+ bbit0.d r1,2,loop_start
+ ror r12,r8
+ sub r2,r3,r8
+ bic_s r2,r2,r3
+ tst_s r2,r12
+ bne r3z
+ mov_s r4,r3
+ .balign 4
+loop:
+ ld.a r3,[r1,4]
+ st.ab r4,[r10,4]
+loop_start:
+ ld.a r4,[r1,4]
+ sub r2,r3,r8
+ bic_s r2,r2,r3
+ tst_s r2,r12
+ bne_s r3z
+ st.ab r3,[r10,4]
+ sub r2,r4,r8
+ bic r2,r2,r4
+ tst r2,r12
+ beq loop
+ mov_s r3,r4
+#ifdef __LITTLE_ENDIAN__
+r3z: bmsk.f r1,r3,7
+ lsr_s r3,r3,8
+#else
+r3z: lsr.f r1,r3,24
+ asl_s r3,r3,8
+#endif
+ bne.d r3z
+ stb.ab r1,[r10,1]
+ j_s [blink]
+
+ .balign 4
+charloop:
+ ldb.ab r3,[r1,1]
+
+
+ brne.d r3,0,charloop
+ stb.ab r3,[r10,1]
+ j [blink]
+ARC_EXIT strcpy
