LXR linux/arch/avr32/lib/memset.S

   1/*
   2 * Copyright (C) 2004-2006 Atmel Corporation
   3 *
   4 * Based on linux/arch/arm/lib/memset.S
   5 *   Copyright (C) 1995-2000 Russell King
   6 *
   7 * This program is free software; you can redistribute it and/or modify
   8 * it under the terms of the GNU General Public License version 2 as
   9 * published by the Free Software Foundation.
  10 *
  11 * ASM optimised string functions
  12 */
  13#include <asm/asm.h>
  14
  15        /*
  16         * r12: void *b
  17         * r11: int c
  18         * r10: size_t len
  19         *
  20         * Returns b in r12
  21         */
  22        .text
  23        .global memset
  24        .type   memset, @function
  25        .align  5
  26memset:
  27        mov     r9, r12
  28        mov     r8, r12
  29        or      r11, r11, r11 << 8
  30        andl    r9, 3, COH
  31        brne    1f
  32
  332:      or      r11, r11, r11 << 16
  34        sub     r10, 4
  35        brlt    5f
  36
  37        /* Let's do some real work */
  384:      st.w    r8++, r11
  39        sub     r10, 4
  40        brge    4b
  41
  42        /*
  43         * When we get here, we've got less than 4 bytes to set. r10
  44         * might be negative.
  45         */
  465:      sub     r10, -4
  47        reteq   r12
  48
  49        /* Fastpath ends here, exactly 32 bytes from memset */
  50
  51        /* Handle unaligned count or pointer */
  52        bld     r10, 1
  53        brcc    6f
  54        st.b    r8++, r11
  55        st.b    r8++, r11
  56        bld     r10, 0
  57        retcc   r12
  586:      st.b    r8++, r11
  59        retal   r12
  60
  61        /* Handle unaligned pointer */
  621:      sub     r10, 4
  63        brlt    5b
  64        add     r10, r9
  65        lsl     r9, 1
  66        add     pc, r9
  67        st.b    r8++, r11
  68        st.b    r8++, r11
  69        st.b    r8++, r11
  70        rjmp    2b
  71
  72        .size   memset, . - memset
  73