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Write a PS/2 Keyboard Driver

hard8/15

Program the PIT for Kernel Preemption Implement Serial Port Output for Kernel Debugging

Language

Compiler

2.0s Limit 256MB

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Implementation

Implement a PS/2 keyboard driver simulation in C.

Requirements:

Define scan code to ASCII lookup tables (unshifted and shifted)
Implement keyboard_handler() that processes scan codes
Distinguish make codes from break codes (break = make + 0x80)
Handle modifier keys: Shift, Ctrl, Alt, Caps Lock
Implement a circular buffer for keystrokes
Implement keyboard_read() that returns translated ASCII
Show scan code translation for letters, numbers, and special keys
Handle special keys: Enter (0x1C), Backspace (0x0E), Escape (0x01)
Print the state of modifier flags as they change

Test:

Show scan code 0x1E ('a') being translated
Show shift handling for scan code 0x1E ('A')
Show caps lock toggling
Show buffer reading multiple keystrokes

Why This Matters

The PS/2 scan-code translation you implement here — make codes, break codes, the shift/caps-lock XOR trick — is exactly what every BIOS and early Linux console driver did before USB HID keyboards became standard. Confusing a break code for a make code is a classic bug that makes a kernel think a key is still held down forever after it's released.

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Validation Suite

main.c

Workspace 1.0

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