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Diffstat (limited to '')
| -rw-r--r-- | README.md | 40 |
1 files changed, 35 insertions, 5 deletions
@@ -193,12 +193,40 @@ void main(void) { } ``` +### libc + +`writes`, `putc`, `puts`, `nl`, `strlen`, `readc` (returns `EOF`=4 at end of +input), `getargs` (this program's argument string), `getpid`, `sexit`. +Arguments: the shell splits the command line at the first space and leaves +`"cmd\0args\0"` at `$A000`; the child inherits it through `fork`, and +`getargs()` returns the args. + +### CLI tools (in `c/`) + +| tool | what it does | +|------|--------------| +| `echo` | print its arguments (`echo hello world`) | +| `cat` | copy stdin to stdout until EOF (Ctrl-D / pipe end) | +| `uname`| print the system name | +| `pid` | print the process's pid (decimal) | +| `true` / `false` | exit 0 / 1 | +| `chello` | the C "hello" demo | + ``` -$ chello -hello from C on gbos! -my pid is 2 +$ uname +gbos sm83 (Game Boy Color) +$ echo C tools on a Game Boy +C tools on a Game Boy +$ pid +5 +$ cat +hi from cat +hi from cat ``` +Each tool is a separate `c/<name>.c`, built to a ROM-bank blob, INCBIN'd, and +registered in the program table + shell command table (`src/programs.asm`). + **Toolchain gotchas found the hard way:** SDCC's `--asm=rgbds` mode mis-orders instructions (emits `ld [hl],a` before the `ld hl,sp+0` that sets the pointer) — so we use SDCC's native asxxxx path and INCBIN the blob instead. String literals @@ -213,8 +241,10 @@ explicit lengths and emit newlines via `nl()`. - [ ] `exec` refinement: copy `.data` from ROM + zero `.bss` for RW globals - [x] a real shell program: `fork`+`exec`+`wait` driven from the serial console - [x] C toolchain: SDCC (sm83) + libc shim, C programs run as gbos processes -- [ ] grow libc (strings, a `main(argc,argv)`, more syscalls) + port real tools -- [ ] Makefile-drive multiple C programs (a `CPROGS` list) +- [x] grow libc (`puts`/`putc`/`strlen`/`getargs`/EOF) + args via the shell +- [x] CLI tools in C: `echo`, `cat`, `uname`, `pid`, `true`, `false` +- [x] Makefile builds all C programs (a `CBLOBS` list) +- [ ] more tools (`wc`, `head`, `rev`), a real `argc/argv`, a RAM filesystem - [ ] Preemptive scheduling: real context save in `TimerISR` → `hSwitchTo` - [ ] Use the `$D000-$DFFF` u-area (SVBK) for per-process kernel state / kstack - [ ] `brk`/heap allocator inside the task bank (heap up, stack down, collision = ENOMEM) |