arch/avr32/lib/clear_user.S

   1 /*
   2  * Copyright 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  */
   8 #include <asm/page.h>
   9 #include <asm/thread_info.h>
  10 #include <asm/asm.h>
  11
  12         .text
  13         .align  1
  14         .global clear_user
  15         .type   clear_user, "function"
  16 clear_user:
  17         branch_if_kernel r8, __clear_user
  18         ret_if_privileged r8, r12, r11, r11
  19
  20         .global __clear_user
  21         .type   __clear_user, "function"
  22 __clear_user:
  23         mov     r9, r12
  24         mov     r8, 0
  25         andl    r9, 3, COH
  26         brne    5f
  27
  28 1:      sub     r11, 4
  29         brlt    2f
  30
  31 10:     st.w    r12++, r8
  32         sub     r11, 4
  33         brge    10b
  34
  35 2:      sub     r11, -4
  36         reteq   0
  37
  38         /* Unaligned count or address */
  39         bld     r11, 1
  40         brcc    12f
  41 11:     st.h    r12++, r8
  42         sub     r11, 2
  43         reteq   0
  44 12:     st.b    r12++, r8
  45         retal   0
  46
  47         /* Unaligned address */
  48 5:      cp.w    r11, 4
  49         brlt    2b
  50
  51         lsl     r9, 2
  52         add     pc, pc, r9
  53 13:     st.b    r12++, r8
  54         sub     r11, 1
  55 14:     st.b    r12++, r8
  56         sub     r11, 1
  57 15:     st.b    r12++, r8
  58         sub     r11, 1
  59         rjmp    1b
  60
  61         .size   clear_user, . - clear_user
  62         .size   __clear_user, . - __clear_user
  63
  64         .section .fixup, "ax"
  65         .align  1
  66 18:     sub     r11, -4
  67 19:     retal   r11
  68
  69         .section __ex_table, "a"
  70         .align  2
  71         .long   10b, 18b
  72         .long   11b, 19b
  73         .long   12b, 19b
  74         .long   13b, 19b
  75         .long   14b, 19b
  76         .long   15b, 19b