diff options
Diffstat (limited to 'PerformanceTests/SunSpider/tests/sunspider-0.9.1/bitops-3bit-bits-in-byte.js')
-rw-r--r-- | PerformanceTests/SunSpider/tests/sunspider-0.9.1/bitops-3bit-bits-in-byte.js | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/PerformanceTests/SunSpider/tests/sunspider-0.9.1/bitops-3bit-bits-in-byte.js b/PerformanceTests/SunSpider/tests/sunspider-0.9.1/bitops-3bit-bits-in-byte.js new file mode 100644 index 0000000..1d85406 --- /dev/null +++ b/PerformanceTests/SunSpider/tests/sunspider-0.9.1/bitops-3bit-bits-in-byte.js @@ -0,0 +1,32 @@ +// 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); |