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Write a PS/2 Keyboard Interrupt Service Routine

hard4/8

Program the PIT for Precise Timing Implement Serial Port Output with UART 16550

Language

Compiler

2.0s Limit 256MB

Submit and pass all tests to enable saving to GitHub.

Implementation

Implement a PS/2 keyboard ISR in C.

Requirements:

Define scan code to ASCII tables
Implement keyboard_isr() that reads port 0x60
Distinguish make codes from break codes
Handle modifier keys: Shift, Ctrl, Alt, Caps Lock
Implement circular buffer for keystrokes
Implement keyboard_read() returning ASCII
Show scan code translation
Handle special keys: Enter, Backspace, Escape
Print modifier state changes
Send EOI in ISR

Test:

Show key press handled
Show shift+key producing uppercase
Show caps lock toggle
Show buffer reading
Show special keys handled

Why This Matters

The Linux kernel's drivers/input/keyboard/atkbd.c and every hobby OS keyboard driver on the OSDev wiki decode Scan Code Set 1 with this exact make-code/break-code (bit 7) distinction and a circular buffer to decouple the ISR from character processing. Forgetting to track Shift/Caps-Lock state independently from the base scancode table is a classic bug that makes a keyboard driver type the wrong case entirely.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0

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