lib_avr32/memset.S

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * See file CREDITS for list of people who contributed to this
   5  * project.
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License as
   9  * published by the Free Software Foundation; either version 2 of
  10  * the License, or (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  20  * MA 02111-1307 USA
  21  */
  22
  23         /*
  24          * r12: void *b
  25          * r11: int c
  26          * r10: size_t len
  27          *
  28          * Returns b in r12
  29          */
  30         .section .text.memset, "ax", @progbits
  31
  32         .global memset
  33         .type   memset, @function
  34         .align  2
  35 memset:
  36         mov     r9, r12
  37         mov     r8, r12
  38         or      r11, r11, r11 << 8
  39         andl    r9, 3, COH
  40         brne    1f
  41
  42 2:      or      r11, r11, r11 << 16
  43         sub     r10, 4
  44         brlt    5f
  45
  46         /* Let's do some real work */
  47 4:      st.w    r8++, r11
  48         sub     r10, 4
  49         brge    4b
  50
  51         /*
  52          * When we get here, we've got less than 4 bytes to set. r10
  53          * might be negative.
  54          */
  55 5:      sub     r10, -4
  56         reteq   r12
  57
  58         /* Fastpath ends here, exactly 32 bytes from memset */
  59
  60         /* Handle unaligned count or pointer */
  61         bld     r10, 1
  62         brcc    6f
  63         st.b    r8++, r11
  64         st.b    r8++, r11
  65         bld     r10, 0
  66         retcc   r12
  67 6:      st.b    r8++, r11
  68         mov     pc, lr
  69
  70         /* Handle unaligned pointer */
  71 1:      sub     r10, 4
  72         brlt    5b
  73         add     r10, r9
  74         lsl     r9, 1
  75         add     pc, r9
  76         st.b    r8++, r11
  77         st.b    r8++, r11
  78         st.b    r8++, r11
  79         rjmp    2b
  80
  81         .size   memset, . - memset