LXR linux/arch/x86/lib/cmpxchg8b

   1/*
   2 *      This program is free software; you can redistribute it and/or
   3 *      modify it under the terms of the GNU General Public License
   4 *      as published by the Free Software Foundation; version 2
   5 *      of the License.
   6 *
   7 */
   8
   9#include <linux/linkage.h>
  10#include <asm/dwarf2.h>
  11
  12.text
  13
  14/*
  15 * Inputs:
  16 * %esi : memory location to compare
  17 * %eax : low 32 bits of old value
  18 * %edx : high 32 bits of old value
  19 * %ebx : low 32 bits of new value
  20 * %ecx : high 32 bits of new value
  21 */
  22ENTRY(cmpxchg8b_emu)
  23CFI_STARTPROC
  24
  25#
  26# Emulate 'cmpxchg8b (%esi)' on UP except we don't
  27# set the whole ZF thing (caller will just compare
  28# eax:edx with the expected value)
  29#
  30        pushfl_cfi
  31        cli
  32
  33        cmpl  (%esi), %eax
  34        jne .Lnot_same
  35        cmpl 4(%esi), %edx
  36        jne .Lhalf_same
  37
  38        movl %ebx,  (%esi)
  39        movl %ecx, 4(%esi)
  40
  41        CFI_REMEMBER_STATE
  42        popfl_cfi
  43        ret
  44
  45        CFI_RESTORE_STATE
  46.Lnot_same:
  47        movl  (%esi), %eax
  48.Lhalf_same:
  49        movl 4(%esi), %edx
  50
  51        popfl_cfi
  52        ret
  53
  54CFI_ENDPROC
  55ENDPROC(cmpxchg8b_emu)
  56