memset.S 2.9 KB

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  1. /*
  2. * linux/arch/alpha/lib/memset.S
  3. *
  4. * This is an efficient (and small) implementation of the C library "memset()"
  5. * function for the alpha.
  6. *
  7. * (C) Copyright 1996 Linus Torvalds
  8. *
  9. * This routine is "moral-ware": you are free to use it any way you wish, and
  10. * the only obligation I put on you is a moral one: if you make any improvements
  11. * to the routine, please send me your improvements for me to use similarly.
  12. *
  13. * The scheduling comments are according to the EV5 documentation (and done by
  14. * hand, so they might well be incorrect, please do tell me about it..)
  15. */
  16. .set noat
  17. .set noreorder
  18. .text
  19. .globl memset
  20. .globl __memset
  21. .globl __memsetw
  22. .globl __constant_c_memset
  23. .ent __memset
  24. .align 5
  25. __memset:
  26. .frame $30,0,$26,0
  27. .prologue 0
  28. and $17,255,$1 /* E1 */
  29. insbl $17,1,$17 /* .. E0 */
  30. bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
  31. sll $17,16,$1 /* E1 (p-c latency, next cycle) */
  32. bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
  33. sll $17,32,$1 /* E1 (p-c latency, next cycle) */
  34. bis $17,$1,$17 /* E0 (p-c latency, next cycle) */
  35. ldq_u $31,0($30) /* .. E1 */
  36. .align 5
  37. __constant_c_memset:
  38. addq $18,$16,$6 /* E0 */
  39. bis $16,$16,$0 /* .. E1 */
  40. xor $16,$6,$1 /* E0 */
  41. ble $18,end /* .. E1 */
  42. bic $1,7,$1 /* E0 */
  43. beq $1,within_one_quad /* .. E1 (note EV5 zero-latency forwarding) */
  44. and $16,7,$3 /* E0 */
  45. beq $3,aligned /* .. E1 (note EV5 zero-latency forwarding) */
  46. ldq_u $4,0($16) /* E0 */
  47. bis $16,$16,$5 /* .. E1 */
  48. insql $17,$16,$2 /* E0 */
  49. subq $3,8,$3 /* .. E1 */
  50. addq $18,$3,$18 /* E0 $18 is new count ($3 is negative) */
  51. mskql $4,$16,$4 /* .. E1 (and possible load stall) */
  52. subq $16,$3,$16 /* E0 $16 is new aligned destination */
  53. bis $2,$4,$1 /* .. E1 */
  54. bis $31,$31,$31 /* E0 */
  55. ldq_u $31,0($30) /* .. E1 */
  56. stq_u $1,0($5) /* E0 */
  57. bis $31,$31,$31 /* .. E1 */
  58. .align 4
  59. aligned:
  60. sra $18,3,$3 /* E0 */
  61. and $18,7,$18 /* .. E1 */
  62. bis $16,$16,$5 /* E0 */
  63. beq $3,no_quad /* .. E1 */
  64. .align 3
  65. loop:
  66. stq $17,0($5) /* E0 */
  67. subq $3,1,$3 /* .. E1 */
  68. addq $5,8,$5 /* E0 */
  69. bne $3,loop /* .. E1 */
  70. no_quad:
  71. bis $31,$31,$31 /* E0 */
  72. beq $18,end /* .. E1 */
  73. ldq $7,0($5) /* E0 */
  74. mskqh $7,$6,$2 /* .. E1 (and load stall) */
  75. insqh $17,$6,$4 /* E0 */
  76. bis $2,$4,$1 /* .. E1 */
  77. stq $1,0($5) /* E0 */
  78. ret $31,($26),1 /* .. E1 */
  79. .align 3
  80. within_one_quad:
  81. ldq_u $1,0($16) /* E0 */
  82. insql $17,$16,$2 /* E1 */
  83. mskql $1,$16,$4 /* E0 (after load stall) */
  84. bis $2,$4,$2 /* E0 */
  85. mskql $2,$6,$4 /* E0 */
  86. mskqh $1,$6,$2 /* .. E1 */
  87. bis $2,$4,$1 /* E0 */
  88. stq_u $1,0($16) /* E0 */
  89. end:
  90. ret $31,($26),1 /* E1 */
  91. .end __memset
  92. .align 5
  93. .ent __memsetw
  94. __memsetw:
  95. .prologue 0
  96. inswl $17,0,$1 /* E0 */
  97. inswl $17,2,$2 /* E0 */
  98. inswl $17,4,$3 /* E0 */
  99. or $1,$2,$1 /* .. E1 */
  100. inswl $17,6,$4 /* E0 */
  101. or $1,$3,$1 /* .. E1 */
  102. or $1,$4,$17 /* E0 */
  103. br __constant_c_memset /* .. E1 */
  104. .end __memsetw
  105. memset = __memset