js/src/jit-test/tests/sunspider/check-bitops-3bit-bits-in-byte.js@6474c204b198 (annotated)
js/src/jit-test/tests/sunspider/check-bitops-3bit-bits-in-byte.js
Wed, 31 Dec 2014 06:09:35 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Wed, 31 Dec 2014 06:09:35 +0100
- changeset 0
- 6474c204b198
- permissions
- -rw-r--r--
Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.
| michael@0 | 1 | // Copyright (c) 2004 by Arthur Langereis (arthur_ext at domain xfinitegames, tld com |
| michael@0 | 2 | |
| michael@0 | 3 | // 1 op = 6 ANDs, 3 SHRs, 3 SHLs, 4 assigns, 2 ADDs |
| michael@0 | 4 | // O(1) |
| michael@0 | 5 | function fast3bitlookup(b) { |
| michael@0 | 6 | var c, bi3b = 0xE994; // 0b1110 1001 1001 0100; // 3 2 2 1 2 1 1 0 |
| michael@0 | 7 | c = 3 & (bi3b >> ((b << 1) & 14)); |
| michael@0 | 8 | c += 3 & (bi3b >> ((b >> 2) & 14)); |
| michael@0 | 9 | c += 3 & (bi3b >> ((b >> 5) & 6)); |
| michael@0 | 10 | return c; |
| michael@0 | 11 | |
| michael@0 | 12 | /* |
| michael@0 | 13 | lir4,0xE994; 9 instructions, no memory access, minimal register dependence, 6 shifts, 2 adds, 1 inline assign |
| michael@0 | 14 | rlwinmr5,r3,1,28,30 |
| michael@0 | 15 | rlwinmr6,r3,30,28,30 |
| michael@0 | 16 | rlwinmr7,r3,27,29,30 |
| michael@0 | 17 | rlwnmr8,r4,r5,30,31 |
| michael@0 | 18 | rlwnmr9,r4,r6,30,31 |
| michael@0 | 19 | rlwnmr10,r4,r7,30,31 |
| michael@0 | 20 | addr3,r8,r9 |
| michael@0 | 21 | addr3,r3,r10 |
| michael@0 | 22 | */ |
| michael@0 | 23 | } |
| michael@0 | 24 | |
| michael@0 | 25 | var ret = 0; |
| michael@0 | 26 | function TimeFunc(func) { |
| michael@0 | 27 | var x, y, t; |
| michael@0 | 28 | for(var x=0; x<500; x++) |
| michael@0 | 29 | for(var y=0; y<256; y++) { |
| michael@0 | 30 | ret += func(y); |
| michael@0 | 31 | } |
| michael@0 | 32 | } |
| michael@0 | 33 | |
| michael@0 | 34 | TimeFunc(fast3bitlookup); |
| michael@0 | 35 | assertEq(ret, 512000) |
