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kernel/linux-rt-4.4.41/arch/x86/lib/atomic64_cx8_32.S 2.71 KB
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  /*
   * atomic64_t for 586+
   *
   * Copyright © 2010  Luca Barbieri
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   */
  
  #include <linux/linkage.h>
  #include <asm/alternative-asm.h>
  
  .macro read64 reg
  	movl %ebx, %eax
  	movl %ecx, %edx
  /* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
  	LOCK_PREFIX
  	cmpxchg8b (\reg)
  .endm
  
  ENTRY(atomic64_read_cx8)
  	read64 %ecx
  	ret
  ENDPROC(atomic64_read_cx8)
  
  ENTRY(atomic64_set_cx8)
  1:
  /* we don't need LOCK_PREFIX since aligned 64-bit writes
   * are atomic on 586 and newer */
  	cmpxchg8b (%esi)
  	jne 1b
  
  	ret
  ENDPROC(atomic64_set_cx8)
  
  ENTRY(atomic64_xchg_cx8)
  1:
  	LOCK_PREFIX
  	cmpxchg8b (%esi)
  	jne 1b
  
  	ret
  ENDPROC(atomic64_xchg_cx8)
  
  .macro addsub_return func ins insc
  ENTRY(atomic64_\func\()_return_cx8)
  	pushl %ebp
  	pushl %ebx
  	pushl %esi
  	pushl %edi
  
  	movl %eax, %esi
  	movl %edx, %edi
  	movl %ecx, %ebp
  
  	read64 %ecx
  1:
  	movl %eax, %ebx
  	movl %edx, %ecx
  	\ins\()l %esi, %ebx
  	\insc\()l %edi, %ecx
  	LOCK_PREFIX
  	cmpxchg8b (%ebp)
  	jne 1b
  
  10:
  	movl %ebx, %eax
  	movl %ecx, %edx
  	popl %edi
  	popl %esi
  	popl %ebx
  	popl %ebp
  	ret
  ENDPROC(atomic64_\func\()_return_cx8)
  .endm
  
  addsub_return add add adc
  addsub_return sub sub sbb
  
  .macro incdec_return func ins insc
  ENTRY(atomic64_\func\()_return_cx8)
  	pushl %ebx
  
  	read64 %esi
  1:
  	movl %eax, %ebx
  	movl %edx, %ecx
  	\ins\()l $1, %ebx
  	\insc\()l $0, %ecx
  	LOCK_PREFIX
  	cmpxchg8b (%esi)
  	jne 1b
  
  10:
  	movl %ebx, %eax
  	movl %ecx, %edx
  	popl %ebx
  	ret
  ENDPROC(atomic64_\func\()_return_cx8)
  .endm
  
  incdec_return inc add adc
  incdec_return dec sub sbb
  
  ENTRY(atomic64_dec_if_positive_cx8)
  	pushl %ebx
  
  	read64 %esi
  1:
  	movl %eax, %ebx
  	movl %edx, %ecx
  	subl $1, %ebx
  	sbb $0, %ecx
  	js 2f
  	LOCK_PREFIX
  	cmpxchg8b (%esi)
  	jne 1b
  
  2:
  	movl %ebx, %eax
  	movl %ecx, %edx
  	popl %ebx
  	ret
  ENDPROC(atomic64_dec_if_positive_cx8)
  
  ENTRY(atomic64_add_unless_cx8)
  	pushl %ebp
  	pushl %ebx
  /* these just push these two parameters on the stack */
  	pushl %edi
  	pushl %ecx
  
  	movl %eax, %ebp
  	movl %edx, %edi
  
  	read64 %esi
  1:
  	cmpl %eax, 0(%esp)
  	je 4f
  2:
  	movl %eax, %ebx
  	movl %edx, %ecx
  	addl %ebp, %ebx
  	adcl %edi, %ecx
  	LOCK_PREFIX
  	cmpxchg8b (%esi)
  	jne 1b
  
  	movl $1, %eax
  3:
  	addl $8, %esp
  	popl %ebx
  	popl %ebp
  	ret
  4:
  	cmpl %edx, 4(%esp)
  	jne 2b
  	xorl %eax, %eax
  	jmp 3b
  ENDPROC(atomic64_add_unless_cx8)
  
  ENTRY(atomic64_inc_not_zero_cx8)
  	pushl %ebx
  
  	read64 %esi
  1:
  	movl %eax, %ecx
  	orl %edx, %ecx
  	jz 3f
  	movl %eax, %ebx
  	xorl %ecx, %ecx
  	addl $1, %ebx
  	adcl %edx, %ecx
  	LOCK_PREFIX
  	cmpxchg8b (%esi)
  	jne 1b
  
  	movl $1, %eax
  3:
  	popl %ebx
  	ret
  ENDPROC(atomic64_inc_not_zero_cx8)