summaryrefslogtreecommitdiffstats
path: root/kernel/arch/alpha/lib/strchr.S
diff options
context:
space:
mode:
authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/arch/alpha/lib/strchr.S
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/arch/alpha/lib/strchr.S')
-rw-r--r--kernel/arch/alpha/lib/strchr.S70
1 files changed, 70 insertions, 0 deletions
diff --git a/kernel/arch/alpha/lib/strchr.S b/kernel/arch/alpha/lib/strchr.S
new file mode 100644
index 000000000..011a175e8
--- /dev/null
+++ b/kernel/arch/alpha/lib/strchr.S
@@ -0,0 +1,70 @@
+/*
+ * arch/alpha/lib/strchr.S
+ * Contributed by Richard Henderson (rth@tamu.edu)
+ *
+ * Return the address of a given character within a null-terminated
+ * string, or null if it is not found.
+ */
+
+#include <asm/regdef.h>
+
+ .set noreorder
+ .set noat
+
+ .align 3
+ .globl strchr
+ .ent strchr
+strchr:
+ .frame sp, 0, ra
+ .prologue 0
+
+ zapnot a1, 1, a1 # e0 : zero extend the search character
+ ldq_u t0, 0(a0) # .. e1 : load first quadword
+ sll a1, 8, t5 # e0 : replicate the search character
+ andnot a0, 7, v0 # .. e1 : align our loop pointer
+ or t5, a1, a1 # e0 :
+ lda t4, -1 # .. e1 : build garbage mask
+ sll a1, 16, t5 # e0 :
+ cmpbge zero, t0, t2 # .. e1 : bits set iff byte == zero
+ mskqh t4, a0, t4 # e0 :
+ or t5, a1, a1 # .. e1 :
+ sll a1, 32, t5 # e0 :
+ cmpbge zero, t4, t4 # .. e1 : bits set iff byte is garbage
+ or t5, a1, a1 # e0 :
+ xor t0, a1, t1 # .. e1 : make bytes == c zero
+ cmpbge zero, t1, t3 # e0 : bits set iff byte == c
+ or t2, t3, t0 # e1 : bits set iff char match or zero match
+ andnot t0, t4, t0 # e0 : clear garbage bits
+ bne t0, $found # .. e1 (zdb)
+
+$loop: ldq t0, 8(v0) # e0 :
+ addq v0, 8, v0 # .. e1 :
+ nop # e0 :
+ xor t0, a1, t1 # .. e1 (ev5 data stall)
+ cmpbge zero, t0, t2 # e0 : bits set iff byte == 0
+ cmpbge zero, t1, t3 # .. e1 : bits set iff byte == c
+ or t2, t3, t0 # e0 :
+ beq t0, $loop # .. e1 (zdb)
+
+$found: negq t0, t1 # e0 : clear all but least set bit
+ and t0, t1, t0 # e1 (stall)
+
+ and t0, t3, t1 # e0 : bit set iff byte was the char
+ beq t1, $retnull # .. e1 (zdb)
+
+ and t0, 0xf0, t2 # e0 : binary search for that set bit
+ and t0, 0xcc, t3 # .. e1 :
+ and t0, 0xaa, t4 # e0 :
+ cmovne t2, 4, t2 # .. e1 :
+ cmovne t3, 2, t3 # e0 :
+ cmovne t4, 1, t4 # .. e1 :
+ addq t2, t3, t2 # e0 :
+ addq v0, t4, v0 # .. e1 :
+ addq v0, t2, v0 # e0 :
+ ret # .. e1 :
+
+$retnull:
+ mov zero, v0 # e0 :
+ ret # .. e1 :
+
+ .end strchr