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authorLinus Torvalds <torvalds@linux-foundation.org>2013-03-02 07:58:56 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-03-02 07:58:56 -0800
commite23b62256a361611cbd45cd1456638f1a5106b5c (patch)
tree472968c961432a1d9d0c3634ca20433f1d9cd29b /arch/arc/lib/strcmp.S
parentaebb2afd5420c860b7fbc3882a323ef1247fbf16 (diff)
parent8ccfe6675fa974bd06d64f74d0fdee6a5267d2aa (diff)
Merge tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull new ARC architecture from Vineet Gupta: "Initial ARC Linux port with some fixes on top for 3.9-rc1: I would like to introduce the Linux port to ARC Processors (from Synopsys) for 3.9-rc1. The patch-set has been discussed on the public lists since Nov and has received a fair bit of review, specially from Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb... The arch bits are in arch/arc, some asm-generic changes (acked by Arnd), a minor change to PARISC (acked by Helge). The series is a touch bigger for a new port for 2 main reasons: 1. It enables a basic kernel in first sub-series and adds ptrace/kgdb/.. later 2. Some of the fallout of review (DeviceTree support, multi-platform- image support) were added on top of orig series, primarily to record the revision history. This updated pull request additionally contains - fixes due to our GNU tools catching up with the new syscall/ptrace ABI - some (minor) cross-arch Kconfig updates." * tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits) ARC: split elf.h into uapi and export it for userspace ARC: Fixup the current ABI version ARC: gdbserver using regset interface possibly broken ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window ARC: make a copy of flat DT ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed" ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled ARC: Fix pt_orig_r8 access ARC: [3.9] Fallout of hlist iterator update ARC: 64bit RTSC timestamp hardware issue ARC: Don't fiddle with non-existent caches ARC: Add self to MAINTAINERS ARC: Provide a default serial.h for uart drivers needing BASE_BAUD ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux ARC: [Review] Multi-platform image #8: platform registers SMP callbacks ARC: [Review] Multi-platform image #7: SMP common code to use callbacks ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core ARC: [Review] Multi-platform image #4: Isolate platform headers ARC: [Review] Multi-platform image #3: switch to board callback ...
Diffstat (limited to 'arch/arc/lib/strcmp.S')
-rw-r--r--arch/arc/lib/strcmp.S96
1 files changed, 96 insertions, 0 deletions
diff --git a/arch/arc/lib/strcmp.S b/arch/arc/lib/strcmp.S
new file mode 100644
index 000000000000..5dc802b45cf3
--- /dev/null
+++ b/arch/arc/lib/strcmp.S
@@ -0,0 +1,96 @@
+/*
+ * 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.
+ */
+
+/* This is optimized primarily for the ARC700.
+ It would be possible to speed up the loops by one cycle / word
+ respective one cycle / byte by forcing double source 1 alignment, unrolling
+ by a factor of two, and speculatively loading the second word / byte of
+ source 1; however, that would increase the overhead for loop setup / finish,
+ and strcmp might often terminate early. */
+
+#include <asm/linkage.h>
+
+ARC_ENTRY strcmp
+ or r2,r0,r1
+ bmsk_s r2,r2,1
+ brne r2,0,.Lcharloop
+ mov_s r12,0x01010101
+ ror r5,r12
+.Lwordloop:
+ ld.ab r2,[r0,4]
+ ld.ab r3,[r1,4]
+ nop_s
+ sub r4,r2,r12
+ bic r4,r4,r2
+ and r4,r4,r5
+ brne r4,0,.Lfound0
+ breq r2,r3,.Lwordloop
+#ifdef __LITTLE_ENDIAN__
+ xor r0,r2,r3 ; mask for difference
+ sub_s r1,r0,1
+ bic_s r0,r0,r1 ; mask for least significant difference bit
+ sub r1,r5,r0
+ xor r0,r5,r1 ; mask for least significant difference byte
+ and_s r2,r2,r0
+ and_s r3,r3,r0
+#endif /* LITTLE ENDIAN */
+ cmp_s r2,r3
+ mov_s r0,1
+ j_s.d [blink]
+ bset.lo r0,r0,31
+
+ .balign 4
+#ifdef __LITTLE_ENDIAN__
+.Lfound0:
+ xor r0,r2,r3 ; mask for difference
+ or r0,r0,r4 ; or in zero indicator
+ sub_s r1,r0,1
+ bic_s r0,r0,r1 ; mask for least significant difference bit
+ sub r1,r5,r0
+ xor r0,r5,r1 ; mask for least significant difference byte
+ and_s r2,r2,r0
+ and_s r3,r3,r0
+ sub.f r0,r2,r3
+ mov.hi r0,1
+ j_s.d [blink]
+ bset.lo r0,r0,31
+#else /* BIG ENDIAN */
+ /* The zero-detection above can mis-detect 0x01 bytes as zeroes
+ because of carry-propagateion from a lower significant zero byte.
+ We can compensate for this by checking that bit0 is zero.
+ This compensation is not necessary in the step where we
+ get a low estimate for r2, because in any affected bytes
+ we already have 0x00 or 0x01, which will remain unchanged
+ when bit 7 is cleared. */
+ .balign 4
+.Lfound0:
+ lsr r0,r4,8
+ lsr_s r1,r2
+ bic_s r2,r2,r0 ; get low estimate for r2 and get ...
+ bic_s r0,r0,r1 ; <this is the adjusted mask for zeros>
+ or_s r3,r3,r0 ; ... high estimate r3 so that r2 > r3 will ...
+ cmp_s r3,r2 ; ... be independent of trailing garbage
+ or_s r2,r2,r0 ; likewise for r3 > r2
+ bic_s r3,r3,r0
+ rlc r0,0 ; r0 := r2 > r3 ? 1 : 0
+ cmp_s r2,r3
+ j_s.d [blink]
+ bset.lo r0,r0,31
+#endif /* ENDIAN */
+
+ .balign 4
+.Lcharloop:
+ ldb.ab r2,[r0,1]
+ ldb.ab r3,[r1,1]
+ nop_s
+ breq r2,0,.Lcmpend
+ breq r2,r3,.Lcharloop
+.Lcmpend:
+ j_s.d [blink]
+ sub r0,r2,r3
+ARC_EXIT strcmp