summaryrefslogtreecommitdiffstats
path: root/kernel/arch/alpha/lib/strcat.S
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/arch/alpha/lib/strcat.S')
-rw-r--r--kernel/arch/alpha/lib/strcat.S52
1 files changed, 52 insertions, 0 deletions
diff --git a/kernel/arch/alpha/lib/strcat.S b/kernel/arch/alpha/lib/strcat.S
new file mode 100644
index 000000000..393f50384
--- /dev/null
+++ b/kernel/arch/alpha/lib/strcat.S
@@ -0,0 +1,52 @@
+/*
+ * arch/alpha/lib/strcat.S
+ * Contributed by Richard Henderson (rth@tamu.edu)
+ *
+ * Append a null-terminated string from SRC to DST.
+ */
+
+ .text
+
+ .align 3
+ .globl strcat
+ .ent strcat
+strcat:
+ .frame $30, 0, $26
+ .prologue 0
+
+ mov $16, $0 # set up return value
+
+ /* Find the end of the string. */
+
+ ldq_u $1, 0($16) # load first quadword (a0 may be misaligned)
+ lda $2, -1
+ insqh $2, $16, $2
+ andnot $16, 7, $16
+ or $2, $1, $1
+ cmpbge $31, $1, $2 # bits set iff byte == 0
+ bne $2, $found
+
+$loop: ldq $1, 8($16)
+ addq $16, 8, $16
+ cmpbge $31, $1, $2
+ beq $2, $loop
+
+$found: negq $2, $3 # clear all but least set bit
+ and $2, $3, $2
+
+ and $2, 0xf0, $3 # binary search for that set bit
+ and $2, 0xcc, $4
+ and $2, 0xaa, $5
+ cmovne $3, 4, $3
+ cmovne $4, 2, $4
+ cmovne $5, 1, $5
+ addq $3, $4, $3
+ addq $16, $5, $16
+ addq $16, $3, $16
+
+ /* Now do the append. */
+
+ mov $26, $23
+ br __stxcpy
+
+ .end strcat