Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / arch / cris / arch-v32 / lib / checksum.S

diff --git a/kernel/arch/cris/arch-v32/lib/checksum.S b/kernel/arch/cris/arch-v32/lib/checksum.S
new file mode 100644 (file)
index 0000000..4a72a94
--- /dev/null
+++ b/kernel/arch/cris/arch-v32/lib/checksum.S
@@ -0,0 +1,88 @@
+/*
+ * A fast checksum routine using movem
+ * Copyright (c) 1998-2007 Axis Communications AB
+ *
+ * csum_partial(const unsigned char * buff, int len, unsigned int sum)
+ */
+
+       .globl  csum_partial
+       .type   csum_partial,@function
+csum_partial:
+
+       ;; r10 - src
+       ;; r11 - length
+       ;; r12 - checksum
+
+       ;; Optimized for large packets
+       subq    10*4, $r11
+       blt     _word_loop
+       move.d  $r11, $acr
+
+       subq    9*4,$sp
+       clearf  c
+       movem   $r8,[$sp]
+
+       ;; do a movem checksum
+
+_mloop:        movem   [$r10+],$r9     ; read 10 longwords
+       ;; Loop count without touching the c flag.
+       addoq   -10*4, $acr, $acr
+       ;; perform dword checksumming on the 10 longwords
+
+       addc    $r0,$r12
+       addc    $r1,$r12
+       addc    $r2,$r12
+       addc    $r3,$r12
+       addc    $r4,$r12
+       addc    $r5,$r12
+       addc    $r6,$r12
+       addc    $r7,$r12
+       addc    $r8,$r12
+       addc    $r9,$r12
+
+       ;; test $acr without trashing carry.
+       move.d  $acr, $acr
+       bpl     _mloop
+       ;; r11 <= acr  is not really needed in the mloop, just using the dslot
+       ;; to prepare for what is needed after mloop.
+       move.d  $acr, $r11
+
+       ;; fold the last carry into r13
+       addc    0, $r12
+       movem   [$sp+],$r8      ; restore regs
+
+_word_loop:
+       addq    10*4,$r11       ; compensate for last loop underflowing length
+
+       moveq   -1,$r9          ; put 0xffff in r9, faster than move.d 0xffff,r9
+       lsrq    16,$r9
+
+       move.d  $r12,$r13
+       lsrq    16,$r13         ; r13 = checksum >> 16
+       and.d   $r9,$r12        ; checksum = checksum & 0xffff
+
+_no_fold:
+       subq    2,$r11
+       blt     _no_words
+       add.d   $r13,$r12       ; checksum += r13
+
+       ;; checksum the rest of the words
+_wloop:        subq    2,$r11
+       bge     _wloop
+       addu.w  [$r10+],$r12
+
+_no_words:
+       addq    2,$r11
+       ;; see if we have one odd byte more
+       bne     _do_byte
+       nop
+       ret
+       move.d  $r12,$r10
+
+_do_byte:
+       ;; copy and checksum the last byte
+       addu.b  [$r10],$r12
+       ret
+       move.d  $r12,$r10
+
+       .size   csum_partial, .-csum_partial