arch/arm/lib/changebit.S

   1 /*
   2  *  linux/arch/arm/lib/changebit.S
   3  *
   4  *  Copyright (C) 1995-1996 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10 #include <linux/linkage.h>
  11 #include <asm/assembler.h>
  12                 .text
  13
  14 /* Purpose  : Function to change a bit
  15  * Prototype: int change_bit(int bit, void *addr)
  16  */
  17 ENTRY(_change_bit_be)
  18                 eor     r0, r0, #0x18           @ big endian byte ordering
  19 ENTRY(_change_bit_le)
  20                 and     r2, r0, #7
  21                 mov     r3, #1
  22                 mov     r3, r3, lsl r2
  23                 save_and_disable_irqs ip, r2
  24                 ldrb    r2, [r1, r0, lsr #3]
  25                 eor     r2, r2, r3
  26                 strb    r2, [r1, r0, lsr #3]
  27                 restore_irqs ip
  28                 RETINSTR(mov,pc,lr)