Understand the x86 Boot Sequence

Simulate the x86 boot sequence in C.

Requirements:

• Define BOOT_STAGE enum for each stage (POST, MBR_LOAD, STAGE1, STAGE2, KERNEL_ENTRY)
• Implement boot_sequence() that progresses through each stage
• Print what happens at each stage with addresses and actions
• Show the transition from real mode to protected mode conceptually
• Display key memory addresses (0x7C00, entry point)
• Simulate POST checking components (memory, disk, keyboard)
• Simulate MBR loading at 0x7C00
• Simulate bootloader loading kernel at 0x100000 (1MB)
• Print a summary of the complete boot flow

Test:

• Show POST completing
• Show MBR loading at 0x7C00
• Show kernel loading at 0x100000
• Show final kernel entry point reached