SN-0804 已核对来源，附原文与上下文。
谢谢 virtualcoin，完美的对比。
Thanks virtualcoin, that's a perfect comparison.
32 位 Windows（2310k）到 32 位 Linux（2500k）的 8% 提速，大概来自 Linux 上更新的 GCC（4.4.3 对 3.4.5）。
The 8% speedup from 32-bit Windows (2310k) to 32-bit Linux (2500k) is probably from the newer version of GCC on Linux (4.4.3 vs 3.4.5).
32 位到 64 位 Linux 的 15% 提速就更神秘了。代码是完全的 32 位。
The 15% speedup from 32-bit to 64-bit Linux is more of a mystery. The code is completely 32-bit.
嗯，我想是 x86-64 多出的那 8 个寄存器在起作用。如果 SHA 能把大部分 16 个状态变量装进寄存器，那会带来显著差异。
Hmm, I think the 8 extra registers added by x86-64 must be what's helping. That would make a significant difference to SHA if it could hold most of the 16 state variables in registers.
