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| CPU Architecture |
LinuxDevCenter.com Real Mode vs Protected Mode
- -- After booting, the BIOS is NO longer used by linux --
- the BIOS procedures must be executed in real mode
- the kernel executes in protected mode
- A real mode address is composed of a segment and an offset
corresponding physical address is given by segment*16 + offset
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| Real vs Protected Addressing Modes |
DeinMeister.de Real vs Protected Mode ( local copy )
- 8086 Real Mode Addressing
- 8086 has 20 address line ( 2^20 = 1M address space )
- 8086 has 16-bit segment registers and 16-bit offset registers
- 80286 Protected Mode Addressing
- 80286 has 24 address line ( 16M Address space )
- 80286 has protected mode ( data and code segments )
- 80286 has paging and memory management
- 80386 Protected Mode Addressing
- 80386 has 32 address line ( 2^32 = 4GB address space )
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