1 files changed, 54 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev67-strcat.S b/arch/alpha/lib/ev67-strcat.S
new file mode 100644
index 000000000000..c426fe3ed72f
--- /dev/null
+++ b/arch/alpha/lib/ev67-strcat.S
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+/*
+ * arch/alpha/lib/ev67-strcat.S
+ * 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Append a null-terminated string from SRC to DST.
+ *
+ * Much of the information about 21264 scheduling/coding comes from:
+ *      Compiler Writer's Guide for the Alpha 21264
+ *      abbreviated as 'CWG' in other comments here
+ *      ftp.digital.com/pub/Digital/info/semiconductor/literature/dsc-library.html
+ * Scheduling notation:
+ *      E       - either cluster
+ *      U       - upper subcluster; U0 - subcluster U0; U1 - subcluster U1
+ *      L       - lower subcluster; L0 - subcluster L0; L1 - subcluster L1
+ * Try not to change the actual algorithm if possible for consistency.
+ * Commentary: It seems bogus to walk the input string twice - once
+ * to determine the length, and then again while doing the copy.
+ * A significant (future) enhancement would be to only read the input
+ * string once.
+ */
+
+
+        .text
+
+        .align 4
+        .globl strcat
+        .ent strcat
+strcat:
+        .frame $30, 0, $26
+        .prologue 0
+
+        mov     $16, $0         # E : set up return value
+        /* Find the end of the string.  */
+        ldq_u   $1, 0($16)      # L : load first quadword (a0 may be misaligned)
+        lda     $2, -1          # E :
+        insqh   $2, $16, $2     # U :
+
+        andnot  $16, 7, $16     # E :
+        or      $2, $1, $1      # E :
+        cmpbge  $31, $1, $2     # E : bits set iff byte == 0
+        bne     $2, $found      # U :
+
+$loop:  ldq     $1, 8($16)      # L :
+        addq    $16, 8, $16     # E :
+        cmpbge  $31, $1, $2     # E :
+        beq     $2, $loop       # U :
+
+$found: cttz    $2, $3          # U0 :
+        addq    $16, $3, $16    # E :
+        /* Now do the append.  */
+        mov     $26, $23        # E :
+        br      __stxcpy        # L0 :
+
+        .end strcat