从“一个弹簧”到“一片森林”：
// Consumer provided a buffer - we MUST fill it (or part of it)
，详情可参考heLLoword翻译官方下载
When VM=1, the protected-mode bit goes low and the Entry PLA selects real-mode entry points -- MOV ES, reg takes the one-line path. Meanwhile, CPL is hardwired to 3 whenever VM=1, so the V86 task always runs at the lowest privilege level, under full paging protection. The OS can use paging to virtualize the 8086's 1 MB address space, even simulating A20 address line wraparound by mapping pages to the same physical frames.
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