SDCC's z80 crt0 puts the reset vector at 0x0000 (jp init) and the init stub
(set SP, call _main) at an absolute .org 0x100. Passing `--code-loc 0x100`
relocated the _CODE segment on top of that init stub, so on reset the CPU
jumped into __clock/_exit (rst 0x08 then ret with a garbage stack) and
derailed into NOP land before ever reaching main — every Z80 C program ran
but drove nothing (z80-led-chaser-c compiled yet the LEDs never moved).
Verified via a standalone chip-WASM harness: with the flag the chaser does 0
LED writes; without it, it walks the bit (8 writes). Pairs with the z80-cpu
RAM map now covering 0x8000-0xFFFF so the crt0's SP=0 stack is real RAM.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Adds a third format to /api/compile-rom: `c` (C source compiled by SDCC
to Z80 bytes). Same chip-program flow as 8080/Z80 asm — write C in a
project file, click Compile, click Run.
Backend:
- backend/app/services/c_compile.py — async SDCC wrapper. Locates the
sdcc binary on PATH (or via SDCC env var, or common Windows install
paths) and shells out with target=mz80 + --code-loc 0x100 --data-loc
0x8000. Parses the resulting Intel HEX into raw ROM bytes. Pure 8080
is rejected with a clear error (SDCC has no 8080 backend; Z80 ROMs
also run on the i8080-cpu chip if you avoid Z80-only ops).
- rom_compile.py: compile_rom is now async; the new c branch delegates
to c_compile. compile_rom_endpoint awaits it.
Frontend:
- romCompileService: RomFormat gains 'c'; formatForFile maps .c/.cpp to
'c'. isChipProgramFile intentionally still excludes .c — disambiguation
happens at the EditorToolbar level.
- EditorToolbar: the chip-program path also fires when a custom-chip
has programFile === activeFile.name (regardless of extension). That
lets .c files route to /api/compile-rom (SDCC) when bound to a CPU
chip, while .c files NOT bound to any chip continue to route to
arduino-cli as before.
Docker:
- Dockerfile.standalone adds `sdcc` to the apt-get install list, so the
prod image ships with SDCC out of the box.
Example:
- /examples/z80-led-chaser-c — z80-cpu chip + chaser.c (a Larson
scanner written in C with __at() MMIO definitions). Compiles cleanly
with SDCC's --code-loc 0x100 default crt0.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
David Montero