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, 90 insertions, 0 deletions

diff --git a/arch/ia64/lib/ip_fast_csum.S b/arch/ia64/lib/ip_fast_csum.S
new file mode 100644
index 000000000000..19674ca2acfc
--- /dev/null
+++ b/arch/ia64/lib/ip_fast_csum.S
@@ -0,0 +1,90 @@
+/*
+ * Optmized version of the ip_fast_csum() function
+ * Used for calculating IP header checksum
+ *
+ * Return: 16bit checksum, complemented
+ *
+ * Inputs:
+ *      in0: address of buffer to checksum (char *)
+ *      in1: length of the buffer (int)
+ *
+ * Copyright (C) 2002 Intel Corp.
+ * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com>
+ */
+
+#include <asm/asmmacro.h>
+
+/*
+ * Since we know that most likely this function is called with buf aligned
+ * on 4-byte boundary and 20 bytes in length, we can execution rather quickly
+ * versus calling generic version of do_csum, which has lots of overhead in
+ * handling various alignments and sizes.  However, due to lack of constrains
+ * put on the function input argument, cases with alignment not on 4-byte or
+ * size not equal to 20 bytes will be handled by the generic do_csum function.
+ */
+
+#define in0     r32
+#define in1     r33
+#define ret0    r8
+
+GLOBAL_ENTRY(ip_fast_csum)
+        .prologue
+        .body
+        cmp.ne  p6,p7=5,in1     // size other than 20 byte?
+        and     r14=3,in0       // is it aligned on 4-byte?
+        add     r15=4,in0       // second source pointer
+        ;;
+        cmp.ne.or.andcm p6,p7=r14,r0
+        ;;
+(p7)    ld4     r20=[in0],8
+(p7)    ld4     r21=[r15],8
+(p6)    br.spnt .generic
+        ;;
+        ld4     r22=[in0],8
+        ld4     r23=[r15],8
+        ;;
+        ld4     r24=[in0]
+        add     r20=r20,r21
+        add     r22=r22,r23
+        ;;
+        add     r20=r20,r22
+        ;;
+        add     r20=r20,r24
+        ;;
+        shr.u   ret0=r20,16     // now need to add the carry
+        zxt2    r20=r20
+        ;;
+        add     r20=ret0,r20
+        ;;
+        shr.u   ret0=r20,16     // add carry again
+        zxt2    r20=r20
+        ;;
+        add     r20=ret0,r20
+        ;;
+        shr.u   ret0=r20,16
+        zxt2    r20=r20
+        ;;
+        add     r20=ret0,r20
+        ;;
+        andcm   ret0=-1,r20
+        .restore sp             // reset frame state
+        br.ret.sptk.many b0
+        ;;
+
+.generic:
+        .prologue
+        .save ar.pfs, r35
+        alloc   r35=ar.pfs,2,2,2,0
+        .save rp, r34
+        mov     r34=b0
+        .body
+        dep.z   out1=in1,2,30
+        mov     out0=in0
+        ;;
+        br.call.sptk.many b0=do_csum
+        ;;
+        andcm   ret0=-1,ret0
+        mov     ar.pfs=r35
+        mov     b0=r34
+        br.ret.sptk.many b0
+END(ip_fast_csum)