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Use QEMU Monitor to Inspect BIOS Entry State

easy2/8

Document the Full Power-On Sequence: From PSU to OS Understand the Reset Vector: Why CPU Starts at 0xFFFFFFF0

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Compiler

2.0s Limit 256MB

Submit and pass all tests to enable saving to GitHub.

Implementation

Use QEMU to inspect the CPU state immediately after power-on.

Requirements:

Start QEMU x86-64 with monitor enabled using -monitor stdio
Pause immediately after start (QEMU pauses by default in monitor mode)
Use info registers to view all register values
Examine memory at the reset vector 0xFFFFFFF0
Document the CS and IP register values
Document the first instruction at the reset vector
Explain why the CPU starts in real mode
Print your findings in a structured format
Use system() to spawn QEMU process and capture output

Why This Matters

QEMU's monitor and its default SeaBIOS firmware are the exact tools OSDev-wiki hobbyists and Linux kernel developers use to single-step a kernel before it ever touches real hardware. The `info registers` / `x/i $pc` workflow you practice here is the same one used to debug why a bootloader hangs before printing a single character.

Hints

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Validation Suite

main.c

Workspace 1.0

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