/js/src/metrics/jint/sunspider/bitops-3bit-bits-in-byte.js

http://github.com/zpao/v8monkey · JavaScript · 37 lines · 14 code · 5 blank · 18 comment · 2 complexity · 68289bcc2de42778b9baee081d3e02f9 MD5 · raw file 

    

  1. // Copyright (c) 2004 by Arthur Langereis (arthur_ext at domain xfinitegames, tld com
    2. 

  2. 

  3. // 1 op = 6 ANDs, 3 SHRs, 3 SHLs, 4 assigns, 2 ADDs
    4. 

  4. // O(1)
    5. 

  5. function fast3bitlookup(b) {
    6. 

  6. var c, bi3b = 0xE994; // 0b1110 1001 1001 0100; // 3 2 2 1  2 1 1 0
    7. 

  7. c  = 3 & (bi3b >> ((b << 1) & 14));
    8. 

  8. c += 3 & (bi3b >> ((b >> 2) & 14));
    9. 

  9. c += 3 & (bi3b >> ((b >> 5) & 6));
    10. 

  10. return c;
    11. 

  11. 

  12. /*
    13. 

  13. lir4,0xE994; 9 instructions, no memory access, minimal register dependence, 6 shifts, 2 adds, 1 inline assign
    14. 

  14. rlwinmr5,r3,1,28,30
    15. 

  15. rlwinmr6,r3,30,28,30
    16. 

  16. rlwinmr7,r3,27,29,30
    17. 

  17. rlwnmr8,r4,r5,30,31
    18. 

  18. rlwnmr9,r4,r6,30,31
    19. 

  19. rlwnmr10,r4,r7,30,31
    20. 

  20. addr3,r8,r9
    21. 

  21. addr3,r3,r10
    22. 

  22. */
    23. 

  23. }
    24. 

  24. 

  25. 

  26. function TimeFunc(func) {
    27. 

  27. var x, y, t;
    28. 

  28. /* BEGIN LOOP */
    29. 

  29. for(var x=0; x<500; x++) {
    30. 

  30. 	/* BEGIN LOOP */
    31. 

  31. for(var y=0; y<256; y++) func(y);
    32. 

  32. 	/* END LOOP */
    33. 

  33. }
    34. 

  34. /* END LOOP */
    35. 

  35. }
    36. 

  36. 

  37. TimeFunc(fast3bitlookup);
    38.