The 386 Register Set
Figure 5-3 on page 45 illustrates the 386's register set. The following subsections provide a brief introduction to these registers and a detailed description of each of them can be found later in the book.
Figure 5-3. 386 Register Set
Control Registers
CR0
32 bits wide. Refer to Figure 5-4 on page 47 and Table 5-2 on page 46. CR0 in the 386 permitted the OS:
To control whether or not the processor is operating in Real or Protected Mode.
Assuming that the processor is in Protected Mode, to control whether or not Paging is enabled.
To discover whether or not a FPU is present.
Assuming that a x87 FPU coprocessor was present on ...
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