/arch/ia64/lib/carta_random.S

https://bitbucket.org/evzijst/gittest · Assembly · 54 lines · 29 code · 3 blank · 22 comment · 0 complexity · 3a03cbc559f2d4f10592d66a6c802b32 MD5 · raw file 

    

  1. /*
    2. 

  2.  * Fast, simple, yet decent quality random number generator based on
    3. 

  3.  * a paper by David G. Carta ("Two Fast Implementations of the
    4. 

  4.  * `Minimal Standard' Random Number Generator," Communications of the
    5. 

  5.  * ACM, January, 1990).
    6. 

  6.  *
    7. 

  7.  * Copyright (C) 2002 Hewlett-Packard Co
    8. 

  8.  *	David Mosberger-Tang <davidm@hpl.hp.com>
    9. 

  9.  */
    10. 

  10. 

  11. #include <asm/asmmacro.h>
    12. 

  12. 

  13. #define a	r2
    14. 

  14. #define m	r3
    15. 

  15. #define lo	r8
    16. 

  16. #define hi	r9
    17. 

  17. #define t0	r16
    18. 

  18. #define t1	r17
    19. 

  19. #define	seed	r32
    20. 

  20. 

  21. GLOBAL_ENTRY(carta_random32)
    22. 

  22. 	movl	a = (16807 << 16) | 16807
    23. 

  23. 	;;
    24. 

  24. 	pmpyshr2.u t0 = a, seed, 0
    25. 

  25. 	pmpyshr2.u t1 = a, seed, 16
    26. 

  26. 	;;
    27. 

  27. 	unpack2.l t0 = t1, t0
    28. 

  28. 	dep	m = -1, r0, 0, 31
    29. 

  29. 	;;
    30. 

  30. 	zxt4	lo = t0
    31. 

  31. 	shr.u	hi = t0, 32
    32. 

  32. 	;;
    33. 

  33. 	dep	t0 = 0, hi, 15, 49	// t0 = (hi & 0x7fff)
    34. 

  34. 	;;
    35. 

  35. 	shl	t0 = t0, 16		// t0 = (hi & 0x7fff) << 16
    36. 

  36. 	shr	t1 = hi, 15		// t1 = (hi >> 15)
    37. 

  37. 	;;
    38. 

  38. 	add	lo = lo, t0
    39. 

  39. 	;;
    40. 

  40. 	cmp.gtu	p6, p0 = lo, m
    41. 

  41. 	;;
    42. 

  42. (p6)	and	lo = lo, m
    43. 

  43. 	;;
    44. 

  44. (p6)	add	lo = 1, lo
    45. 

  45. 	;;
    46. 

  46. 	add	lo = lo, t1
    47. 

  47. 	;;
    48. 

  48. 	cmp.gtu p6, p0 = lo, m
    49. 

  49. 	;;
    50. 

  50. (p6)	and	lo = lo, m
    51. 

  51. 	;;
    52. 

  52. (p6)	add	lo = 1, lo
    53. 

  53. 	br.ret.sptk.many rp
    54. 

  54. END(carta_random32)
    55.