Home Explore Help
Register Sign In
phyus
/
linux-vybrid_public
8
0
Fork 0
Files Issues 0 Pull Requests 0 Wiki
Tree: 1a34456bbb
Branches Tags
linux-vybrid_pu...
/
arch
/
x86_64
/
lib
/
clear_page.S

clear_page.S 791 B
History Raw

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950 
  1. /*
    2. 

  2.  * Zero a page. 	
    3. 

  3.  * rdi	page
    4. 

  4.  */			
    5. 

  5. 	.globl clear_page
    6. 

  6. 	.p2align 4
    7. 

  7. clear_page:
    8. 

  8. 	xorl   %eax,%eax
    9. 

  9. 	movl   $4096/64,%ecx
    10. 

  10. 	.p2align 4
    11. 

  11. .Lloop:
    12. 

  12. 	decl	%ecx
    13. 

  13. #define PUT(x) movq %rax,x*8(%rdi)
    14. 

  14. 	movq %rax,(%rdi)
    15. 

  15. 	PUT(1)
    16. 

  16. 	PUT(2)
    17. 

  17. 	PUT(3)
    18. 

  18. 	PUT(4)
    19. 

  19. 	PUT(5)
    20. 

  20. 	PUT(6)
    21. 

  21. 	PUT(7)
    22. 

  22. 	leaq	64(%rdi),%rdi
    23. 

  23. 	jnz	.Lloop
    24. 

  24. 	nop
    25. 

  25. 	ret
    26. 

  26. clear_page_end:
    27. 

  27. 

  28. 	/* Some CPUs run faster using the string instructions.
    29. 

  29. 	   It is also a lot simpler. Use this when possible */
    30. 

  30. 

  31. #include <asm/cpufeature.h>
    32. 

  32. 

  33. 	.section .altinstructions,"a"
    34. 

  34. 	.align 8
    35. 

  35. 	.quad  clear_page
    36. 

  36. 	.quad  clear_page_c
    37. 

  37. 	.byte  X86_FEATURE_REP_GOOD
    38. 

  38. 	.byte  clear_page_end-clear_page
    39. 

  39. 	.byte  clear_page_c_end-clear_page_c
    40. 

  40. 	.previous
    41. 

  41. 

  42. 	.section .altinstr_replacement,"ax"
    43. 

  43. clear_page_c:
    44. 

  44. 	movl $4096/8,%ecx
    45. 

  45. 	xorl %eax,%eax
    46. 

  46. 	rep 
    47. 

  47. 	stosq
    48. 

  48. 	ret
    49. 

  49. clear_page_c_end:
    50. 

  50. 	.previous
    51.