Lab 3 Tasks

Requested Functions

• int kbc_read_status(uint8_t *status)
• int kbc_read_output(uint8_t *byte)
• int kbc_write_command(uint8_t command)
• int kbd_process_byte(uint8_t byte)
• int kbd_get_scancode(uint8_t bytes[2], uint8_t *size, int *make)

Guided Gaps

• Check output pointer arguments.
• Ignore reads when no byte is available.
• Detect controller error bits.
• Store a pending 0xE0 prefix.
• Report make and break without losing original bytes.

IMPORTANT

Do not treat every byte as a complete scancode. Extended scancodes must be assembled before the API reports an event.

Common Mistakes

• Clearing parser state too early.
• Reporting a scancode before all bytes arrived.
• Treating break codes as normal key presses.
• Reading output without checking status.

Next: checks and references.