summaryrefslogtreecommitdiffstats
path: root/kernel/arch/arc/lib/strchr-700.S
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/arch/arc/lib/strchr-700.S')
-rw-r--r--kernel/arch/arc/lib/strchr-700.S133
1 files changed, 133 insertions, 0 deletions
diff --git a/kernel/arch/arc/lib/strchr-700.S b/kernel/arch/arc/lib/strchr-700.S
new file mode 100644
index 000000000..b725d5862
--- /dev/null
+++ b/kernel/arch/arc/lib/strchr-700.S
@@ -0,0 +1,133 @@
+/*
+ * 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.
+ */
+
+/* ARC700 has a relatively long pipeline and branch prediction, so we want
+ to avoid branches that are hard to predict. On the other hand, the
+ presence of the norm instruction makes it easier to operate on whole
+ words branch-free. */
+
+#include <linux/linkage.h>
+
+ENTRY(strchr)
+ extb_s r1,r1
+ asl r5,r1,8
+ bmsk r2,r0,1
+ or r5,r5,r1
+ mov_s r3,0x01010101
+ breq.d r2,r0,.Laligned
+ asl r4,r5,16
+ sub_s r0,r0,r2
+ asl r7,r2,3
+ ld_s r2,[r0]
+#ifdef __LITTLE_ENDIAN__
+ asl r7,r3,r7
+#else
+ lsr r7,r3,r7
+#endif
+ or r5,r5,r4
+ ror r4,r3
+ sub r12,r2,r7
+ bic_s r12,r12,r2
+ and r12,r12,r4
+ brne.d r12,0,.Lfound0_ua
+ xor r6,r2,r5
+ ld.a r2,[r0,4]
+ sub r12,r6,r7
+ bic r12,r12,r6
+#ifdef __LITTLE_ENDIAN__
+ and r7,r12,r4
+ breq r7,0,.Loop ; For speed, we want this branch to be unaligned.
+ b .Lfound_char ; Likewise this one.
+#else
+ and r12,r12,r4
+ breq r12,0,.Loop ; For speed, we want this branch to be unaligned.
+ lsr_s r12,r12,7
+ bic r2,r7,r6
+ b.d .Lfound_char_b
+ and_s r2,r2,r12
+#endif
+; /* We require this code address to be unaligned for speed... */
+.Laligned:
+ ld_s r2,[r0]
+ or r5,r5,r4
+ ror r4,r3
+; /* ... so that this code address is aligned, for itself and ... */
+.Loop:
+ sub r12,r2,r3
+ bic_s r12,r12,r2
+ and r12,r12,r4
+ brne.d r12,0,.Lfound0
+ xor r6,r2,r5
+ ld.a r2,[r0,4]
+ sub r12,r6,r3
+ bic r12,r12,r6
+ and r7,r12,r4
+ breq r7,0,.Loop /* ... so that this branch is unaligned. */
+ ; Found searched-for character. r0 has already advanced to next word.
+#ifdef __LITTLE_ENDIAN__
+/* We only need the information about the first matching byte
+ (i.e. the least significant matching byte) to be exact,
+ hence there is no problem with carry effects. */
+.Lfound_char:
+ sub r3,r7,1
+ bic r3,r3,r7
+ norm r2,r3
+ sub_s r0,r0,1
+ asr_s r2,r2,3
+ j.d [blink]
+ sub_s r0,r0,r2
+
+ .balign 4
+.Lfound0_ua:
+ mov r3,r7
+.Lfound0:
+ sub r3,r6,r3
+ bic r3,r3,r6
+ and r2,r3,r4
+ or_s r12,r12,r2
+ sub_s r3,r12,1
+ bic_s r3,r3,r12
+ norm r3,r3
+ add_s r0,r0,3
+ asr_s r12,r3,3
+ asl.f 0,r2,r3
+ sub_s r0,r0,r12
+ j_s.d [blink]
+ mov.pl r0,0
+#else /* BIG ENDIAN */
+.Lfound_char:
+ lsr r7,r7,7
+
+ bic r2,r7,r6
+.Lfound_char_b:
+ norm r2,r2
+ sub_s r0,r0,4
+ asr_s r2,r2,3
+ j.d [blink]
+ add_s r0,r0,r2
+
+.Lfound0_ua:
+ mov_s r3,r7
+.Lfound0:
+ asl_s r2,r2,7
+ or r7,r6,r4
+ bic_s r12,r12,r2
+ sub r2,r7,r3
+ or r2,r2,r6
+ bic r12,r2,r12
+ bic.f r3,r4,r12
+ norm r3,r3
+
+ add.pl r3,r3,1
+ asr_s r12,r3,3
+ asl.f 0,r2,r3
+ add_s r0,r0,r12
+ j_s.d [blink]
+ mov.mi r0,0
+#endif /* ENDIAN */
+END(strchr)