Eric Lee / smarc-fsl-linux-kernel

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Commit dfc349402de8e95f6a42e8341e9ea193b718eee3

Authored by Stuart Menefy
Committed by Paul Mundt
1 parent a0458b07c1

sh: Optimised memset for SH4 

Optimised version of memset for the SH4 which uses movca.l.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

Showing 2 changed files with 112 additions and 2 deletions Side-by-side Diff

arch/sh/lib/Makefile
Diff comments   View file @ dfc3494
... ... @@ -2,7 +2,7 @@
2 2 # Makefile for SuperH-specific library files..
3 3 #
4 4  
5   -lib-y = delay.o memset.o memmove.o memchr.o \
  5 +lib-y = delay.o memmove.o memchr.o \
6 6 checksum.o strlen.o div64.o div64-generic.o
7 7  
8 8 # Extracted from libgcc
9 9  
... ... @@ -23,9 +23,12 @@
23 23 memcpy-y := memcpy.o
24 24 memcpy-$(CONFIG_CPU_SH4) := memcpy-sh4.o
25 25  
  26 +memset-y := memset.o
  27 +memset-$(CONFIG_CPU_SH4) := memset-sh4.o
  28 +
26 29 lib-$(CONFIG_MMU) += copy_page.o __clear_user.o
27 30 lib-$(CONFIG_MCOUNT) += mcount.o
28   -lib-y += $(memcpy-y) $(udivsi3-y)
  31 +lib-y += $(memcpy-y) $(memset-y) $(udivsi3-y)
29 32  
30 33 EXTRA_CFLAGS += -Werror
arch/sh/lib/memset-sh4.S
Diff comments   View file @ dfc3494
  1 +/*
  2 + * "memset" implementation for SH4
  3 + *
  4 + * Copyright (C) 1999 Niibe Yutaka
  5 + * Copyright (c) 2009 STMicroelectronics Limited
  6 + * Author: Stuart Menefy <stuart.menefy:st.com>
  7 + */
  8 +
  9 +/*
  10 + * void *memset(void *s, int c, size_t n);
  11 + */
  12 +
  13 +#include <linux/linkage.h>
  14 +
  15 +ENTRY(memset)
  16 + mov #12,r0
  17 + add r6,r4
  18 + cmp/gt r6,r0
  19 + bt/s 40f ! if it's too small, set a byte at once
  20 + mov r4,r0
  21 + and #3,r0
  22 + cmp/eq #0,r0
  23 + bt/s 2f ! It's aligned
  24 + sub r0,r6
  25 +1:
  26 + dt r0
  27 + bf/s 1b
  28 + mov.b r5,@-r4
  29 +2: ! make VVVV
  30 + extu.b r5,r5
  31 + swap.b r5,r0 ! V0
  32 + or r0,r5 ! VV
  33 + swap.w r5,r0 ! VV00
  34 + or r0,r5 ! VVVV
  35 +
  36 + ! Check if enough bytes need to be copied to be worth the big loop
  37 + mov #0x40, r0 ! (MT)
  38 + cmp/gt r6,r0 ! (MT) 64 > len => slow loop
  39 +
  40 + bt/s 22f
  41 + mov r6,r0
  42 +
  43 + ! align the dst to the cache block size if necessary
  44 + mov r4, r3
  45 + mov #~(0x1f), r1
  46 +
  47 + and r3, r1
  48 + cmp/eq r3, r1
  49 +
  50 + bt/s 11f ! dst is already aligned
  51 + sub r1, r3 ! r3-r1 -> r3
  52 + shlr2 r3 ! number of loops
  53 +
  54 +10: mov.l r5,@-r4
  55 + dt r3
  56 + bf/s 10b
  57 + add #-4, r6
  58 +
  59 +11: ! dst is 32byte aligned
  60 + mov r6,r2
  61 + mov #-5,r0
  62 + shld r0,r2 ! number of loops
  63 +
  64 + add #-32, r4
  65 + mov r5, r0
  66 +12:
  67 + movca.l r0,@r4
  68 + mov.l r5,@(4, r4)
  69 + mov.l r5,@(8, r4)
  70 + mov.l r5,@(12,r4)
  71 + mov.l r5,@(16,r4)
  72 + mov.l r5,@(20,r4)
  73 + add #-0x20, r6
  74 + mov.l r5,@(24,r4)
  75 + dt r2
  76 + mov.l r5,@(28,r4)
  77 + bf/s 12b
  78 + add #-32, r4
  79 +
  80 + add #32, r4
  81 + mov #8, r0
  82 + cmp/ge r0, r6
  83 + bf 40f
  84 +
  85 + mov r6,r0
  86 +22:
  87 + shlr2 r0
  88 + shlr r0 ! r0 = r6 >> 3
  89 +3:
  90 + dt r0
  91 + mov.l r5,@-r4 ! set 8-byte at once
  92 + bf/s 3b
  93 + mov.l r5,@-r4
  94 + !
  95 + mov #7,r0
  96 + and r0,r6
  97 +
  98 + ! fill bytes (length may be zero)
  99 +40: tst r6,r6
  100 + bt 5f
  101 +4:
  102 + dt r6
  103 + bf/s 4b
  104 + mov.b r5,@-r4
  105 +5:
  106 + rts
  107 + mov r4,r0