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, 88 insertions, 0 deletions

diff --git a/arch/alpha/lib/ev67-strchr.S b/arch/alpha/lib/ev67-strchr.S
new file mode 100644
index 000000000000..fbb7b4ffade9
--- /dev/null
+++ b/arch/alpha/lib/ev67-strchr.S
@@ -0,0 +1,88 @@
+/*
+ * arch/alpha/lib/ev67-strchr.S
+ * 21264 version contributed by Rick Gorton <rick.gorton@alpha-processor.com>
+ *
+ * Return the address of a given character within a null-terminated
+ * string, or null if it is not found.
+ *
+ * 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.
+ */
+
+#include <asm/regdef.h>
+
+        .set noreorder
+        .set noat
+
+        .align 4
+        .globl strchr
+        .ent strchr
+strchr:
+        .frame sp, 0, ra
+        .prologue 0
+
+        ldq_u   t0, 0(a0)       # L : load first quadword Latency=3
+        and     a1, 0xff, t3    # E : 00000000000000ch
+        insbl   a1, 1, t5       # U : 000000000000ch00
+        insbl   a1, 7, a2       # U : ch00000000000000
+
+        insbl   t3, 6, a3       # U : 00ch000000000000
+        or      t5, t3, a1      # E : 000000000000chch
+        andnot  a0, 7, v0       # E : align our loop pointer
+        lda     t4, -1          # E : build garbage mask
+
+        mskqh   t4, a0, t4      # U : only want relevant part of first quad
+        or      a2, a3, a2      # E : chch000000000000
+        inswl   a1, 2, t5       # E : 00000000chch0000
+        inswl   a1, 4, a3       # E : 0000chch00000000
+
+        or      a1, a2, a1      # E : chch00000000chch
+        or      a3, t5, t5      # E : 0000chchchch0000
+        cmpbge  zero, t0, t2    # E : bits set iff byte == zero
+        cmpbge  zero, t4, t4    # E : bits set iff byte is garbage
+
+        /* This quad is _very_ serialized.  Lots of stalling happens */
+        or      t5, a1, a1      # E : chchchchchchchch
+        xor     t0, a1, t1      # E : make bytes == c zero
+        cmpbge  zero, t1, t3    # E : bits set iff byte == c
+        or      t2, t3, t0      # E : bits set iff char match or zero match
+
+        andnot  t0, t4, t0      # E : clear garbage bits
+        cttz    t0, a2          # U0 : speculative (in case we get a match)
+        nop                     # E :
+        bne     t0, $found      # U :
+
+        /*
+         * Yuk.  This loop is going to stall like crazy waiting for the
+         * data to be loaded.  Not much can be done about it unless it's
+         * unrolled multiple times - is that safe to do in kernel space?
+         * Or would exception handling recovery code do the trick here?
+         */
+$loop:  ldq     t0, 8(v0)       # L : Latency=3
+        addq    v0, 8, v0       # E :
+        xor     t0, a1, t1      # E :
+        cmpbge  zero, t0, t2    # E : bits set iff byte == 0
+
+        cmpbge  zero, t1, t3    # E : bits set iff byte == c
+        or      t2, t3, t0      # E :
+        cttz    t3, a2          # U0 : speculative (in case we get a match)
+        beq     t0, $loop       # U :
+
+$found: negq    t0, t1          # E : clear all but least set bit
+        and     t0, t1, t0      # E :
+        and     t0, t3, t1      # E : bit set iff byte was the char
+        addq    v0, a2, v0      # E : Add in the bit number from above
+
+        cmoveq  t1, $31, v0     # E : Two mapping slots, latency = 2
+        nop
+        nop
+        ret                     # L0 :
+
+        .end strchr