Adding interrupt handling to the bare metal x86 code
In the previous recipe, we displayed the "hello world" program on bare metal. Next, we'll add interrupt handling and enable keyboard support.
Getting ready
Get the code from the last recipe and ensure that it still compiles and runs. We will be adding to it here.
How to do it…
Execute the following steps to add interrupt handling to bare metal x86 code:
Declare the constants and data structures needed to communicate with the hardware. The definitions can be translated from the hardware manuals.
Write an empty interrupt handler with a
nakedinline assembly that does nothing except return with theiretdinstruction.Write a keyboard interrupt handler with a
nakedinline assembly. We'll need to read the byte using the keyboard from I/O port0x60using theinassembly instruction. Then, store it in a global variable, acknowledge the interrupt, then clean up. (The stack and all registers must be left in the same state they were in when we entered...
