게임보이 어드밴스 상의 유닉스

The simulator contains SIMH at its core. I have attempted to make minimal modifications to SIMH itself, abstracting GBA specific functionality into a logically separate layer that SIMH talks to. This layer could be thought of as having the following components:

TTY Output: gbaunix provides an illusion of a text terminal to SIMH. All TTY output is re-routed to GBA routines that format it, and send it to the GBA's framebuffer. Text-scrolling is done, if necessary. printf() is implicitly converted to a two step operation: sprintf() into a formatting buffer, followed by displaying the buffer on the screen.
TTY Input: gbaunix does not have an input mechanism currently. You can only execute a canned sequence of UNIX shell commands. The sequence must be specified at compile-time as an array of strings in gba/gba_kbd.h in the source. While UNIX is running, pressing the START button feeds the next command line into the TTY's input buffer. gbaunix can either simply poll for keypresses, or can use the GBA's keypad interrupt. The latter ensures that no keypresses are missed. An example sequence is shown below:

/* gba/gba_kbd.h */

const char *gba_kbdinput[] = {
"unix\r",
"root\r",
"chdir /work\r",
"ls -l\r",
"./fact 100\r",
"cat hanoi.c\r",
"./hanoi\r",
"./hanoi 3\r",
"chdir /tmp\r",
"echo 'main() { printf(\"Hello, World!\\n\"); }' \
> hello.c\r",
"cc hello.c\r",
"./a.out\r",
... /* more commands */
NULL,
};