0xffff0和BIOS [英] 0xffff0 and the BIOS

问题描述

首次启动PC时，它将从物理地址0xffff0开始执行.该地址包含对BIOS的jmp指令.

When a pc first boots up, it starts executing at physical address 0xffff0. This address contains a jmp instruction to the BIOS.

现在，对于我的问题，我始终假设物理地址已映射到RAM.如果RAM最初包含垃圾值，那么究竟将jmp指令放入0xffff0是什么呢?对于不同的BIOS，jmp指令是否总是相同或不同?那么0xffff0是否会从RAM映射到BIOS(意味着它是硬映射")?

Now for my question, I always assume the physical addresses are mapped to RAM. If RAM initially contains garbage values, what exactly puts the jmp instruction in 0xffff0? Is the jmp instruction always the same or is it different for different BIOS's? Does 0xffff0 map from RAM to BIOS then (meaning it's "hard mapped")?

推荐答案

前64kB左右映射到BIOS ROM，而不是RAM.

The top 64kB or so are mapped to BIOS ROM, not RAM.

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