Speeding up virtual memory
if (n <= 1) return;
。Line官方版本下载对此有专业解读
Александра Лисица (Редактор отдела «Забота о себе»)
The 386 microcode sequencer has a one-cycle pipeline delay: when a jump or RNI (run next instruction) is decoded, the micro-instruction immediately after it has already been fetched and will execute before the jump takes effect. This "delay slot" is a basic property of the sequencer, and the microcode is written to fill it with useful work rather than waste a cycle on a bubble. The examples in the PTSAV section above show this: at 582/5AE, the micro-instruction after LCALL executes before the subroutine begins.