Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev67-strlen.S b/arch/alpha/lib/ev67-strlen.S
new file mode 100644
index 000000000000..503928072523
--- /dev/null
+++ b/arch/alpha/lib/ev67-strlen.S
@@ -0,0 +1,49 @@
+/*
+ * arch/alpha/lib/ev67-strlen.S
+ * 21264 version by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Finds length of a 0-terminated string.  Optimized for the
+ * Alpha architecture:
+ *
+ *      - memory accessed as aligned quadwords only
+ *      - uses bcmpge to compare 8 bytes in parallel
+ *
+ * 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
+ */
+
+        .set noreorder
+        .set noat
+
+        .globl  strlen
+        .ent    strlen
+        .align 4
+strlen:
+        ldq_u   $1, 0($16)      # L : load first quadword ($16  may be misaligned)
+        lda     $2, -1($31)     # E :
+        insqh   $2, $16, $2     # U :
+        andnot  $16, 7, $0      # E :
+
+        or      $2, $1, $1      # E :
+        cmpbge  $31, $1, $2     # E : $2  <- bitmask: bit i == 1 <==> i-th byte == 0
+        nop                     # E :
+        bne     $2, $found      # U :
+
+$loop:  ldq     $1, 8($0)       # L :
+        addq    $0, 8, $0       # E : addr += 8
+        cmpbge  $31, $1, $2     # E :
+        beq     $2, $loop       # U :
+
+$found:
+        cttz    $2, $3          # U0 :
+        addq    $0, $3, $0      # E :
+        subq    $0, $16, $0     # E :
+        ret     $31, ($26)      # L0 :
+
+        .end    strlen