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| |
| <title>SunSpider bitops-3bit-bits-in-byte</title> |
| <link rel="stylesheet" href="sunspider.css"> |
| </head> |
| |
| <body> |
| <h3>bitops-3bit-bits-in-byte</h3> |
| <div id="console"> |
| </div> |
| <script src="sunspider-record-result.js"></script> |
| <script> |
| |
| var _sunSpiderStartDate = new Date(); |
| |
| // Copyright (c) 2004 by Arthur Langereis (arthur_ext at domain xfinitegames, tld com |
| |
| // 1 op = 6 ANDs, 3 SHRs, 3 SHLs, 4 assigns, 2 ADDs |
| // O(1) |
| function fast3bitlookup(b) { |
| var c, bi3b = 0xE994; // 0b1110 1001 1001 0100; // 3 2 2 1 2 1 1 0 |
| c = 3 & (bi3b >> ((b << 1) & 14)); |
| c += 3 & (bi3b >> ((b >> 2) & 14)); |
| c += 3 & (bi3b >> ((b >> 5) & 6)); |
| return c; |
| |
| /* |
| lir4,0xE994; 9 instructions, no memory access, minimal register dependence, 6 shifts, 2 adds, 1 inline assign |
| rlwinmr5,r3,1,28,30 |
| rlwinmr6,r3,30,28,30 |
| rlwinmr7,r3,27,29,30 |
| rlwnmr8,r4,r5,30,31 |
| rlwnmr9,r4,r6,30,31 |
| rlwnmr10,r4,r7,30,31 |
| addr3,r8,r9 |
| addr3,r3,r10 |
| */ |
| } |
| |
| |
| function TimeFunc(func) { |
| var x, y, t; |
| for(var x=0; x<500; x++) |
| for(var y=0; y<256; y++) func(y); |
| } |
| |
| TimeFunc(fast3bitlookup); |
| |
| |
| var _sunSpiderInterval = new Date() - _sunSpiderStartDate; |
| |
| record(_sunSpiderInterval); |
| </script> |
| |
| |
| </body> |
| </html> |
