Compiler

A minimal C compiler for my custom 16-bit RISC architecture, capable of compiling itself.

Currently does two passes:

1. Parse to AST (also analyzes variable lifetime)
2. Generate Code from AST (no IR, fprintf straight to output file)

Example

Source	Assembly
struct coord { int x; int y; }; int foo (int n, struct coord* coords) { int sum = 0; for (int i = 0; i < n; i++) sum += coords[i].x * coords[i].y; return sum; }	_foo: mov r0, 0 mov r1, 0 for_loop0: sub rz, r1, [sp-2] jmp_ns for_break0 mul r2, r1, 2 add r2, [sp-3] mul r3, r1, 2 add r3, [sp-3] add r3, 1 mov r5, [r3] mul r4, [r2], r5 add r0, r4 for_continue0: add r1, 1 jmp for_loop0 for_break0: mov [sp-2], r0 sub sp, 1 mov ip, [sp]

Limitations

This is not a conformant C compiler (at all!). Here are the most important things that are missing or different

• Type conversion behaviour is different
• Parsing is not quite the same as in standard C
• Preprocessor only supports #include, #define, #ifdef, and #pragma once
• Primitives are:
  • int (alias int16, int16_t)
  • uint (alias uint16, uint16_t, size_t, char)
  • int32 (alias int32_t)
  • uint32 (alias uint32_t)
  • fixed (8.8 fixed point)

These are just off the top of my head, there surely are many others!

Building

Just a CMake project, so

> mkdir bin
> cd bin
> cmake ..

followed by

> cmake --build .

Usage

There are no command-line switches as of now, so just

> ./comp [SOURCE FILES..]

This will generate assembly in out.s and data in data.bin.