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lessons 8, 9, 10, entering 32-bit mode

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Carlos Fenollosa 2014-10-09 11:42:38 +02:00
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09-32bit-gdt/README.md
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@ -19,9 +19,9 @@ but it's good enough to boot, we'll fix this later with a higher language.
As a curiosity, the first GDT entry must be `0x00` to make sure that the As a curiosity, the first GDT entry must be `0x00` to make sure that the
programmer didn't make any mistakes managing addresses. programmer didn't make any mistakes managing addresses.
Furthermore, since the CPU needs to know how long the GDT is, we'll use Furthermore, the CPU can't directly load the GDT address, but it requires
a meta structure called the "GDT descriptor" with the size (16b) and address a meta structure called the "GDT descriptor" with the size (16b) and address
(32b) of our actual GDT. (32b) of our actual GDT. It is loaded with the `lgdt` operation.
Let's directly jump to the GDT code in assembly. Again, to understand Let's directly jump to the GDT code in assembly. Again, to understand
all the segment flags, refer to the os-dev.pdf document. The theory for all the segment flags, refer to the os-dev.pdf document. The theory for