Update README.md

README.md

@@ -1,12 +1,85 @@
-http://vxcc.vxcc.dev/
+# VXCC
+optimizing, small, simple, compiler backend.
 
-# building
-use the `./build.sh`
+VXCC uses SSA IR with block arguments instead of the commonly used phi-nodes.
 
-## deps 
+## compilation stages
+- frontend generates non-SSA IR
+- backend converts it to SSA
+- backend applies optimizations
+- backend converts it to "LL IR" (non-SSA + labels) and performs some more optimizations
+- simple code generation
+
+## goals
+- easily modifyable and readable code
+- not much special knowladge required
+- easy to implement code generation for any architecture
+- make it easy for people to learn about compiler backends
+- good-ish optimizations
+- beat QBE
+
+## **non**-goals
+- reach complexity of GCC or even LLVM
+- beat GCC or LLVM
+
+## frontends
+- [C3](https://c3-lang.org/) compiler [fork](https://github.com/alex-s168/c3c)
+
+## current status
+| goal                                    |   | progress |
+| --------------------------------------- | - | -------- |
+| x86 codegen                             | ![#33cc33](https://placehold.co/15x15/33cc33/33cc33.png) | done but will be re-made |
+| codegen of basic code involving loops   | ![#33cc33](https://placehold.co/15x15/33cc33/33cc33.png) | done    |
+| basic optimizations                     | ![#33cc33](https://placehold.co/15x15/33cc33/33cc33.png) | done    |
+| struct support                          | ![#ff9900](https://placehold.co/15x15/ff9900/ff9900.png) | soon    |
+| proper register allocator & ISEL rework | ![#ff9900](https://placehold.co/15x15/ff9900/ff9900.png) | soon    |
+| floating point numbers                  | ![#cc0000](https://placehold.co/15x15/cc0000/cc0000.png) | planned |
+
+## building
+use the `./build.sh build`
+
+## compile dependencies 
 `clang`: different C compiler can be used by doing `CC=someothercc ./build.sh [build|test]` (`test` can be executed after `build` to run all tests)
 
 `python3`: it is recommended to create a venv in the repository root using `python -m venv venv`
 
-## include into projects
-Link with `build/lib.a` and `build/x86.a`
+## including into projects
+Link with all files returned by `./build.sh libfiles` (at time of writing, `build/lib.a` and `allib/build/all.a`)
+
+## using VXCC in a compiler
+this is meant to be extremely easy to do (for the frontend developer)
+
+currently there is no documentation, but you can look at the [C3C fork](https://github.com/alex-s168/c3c) in the `src/compiler/vxcc_*` files.
+
+If you have any questions, you can ask me on Discord (`alex_s168`) or send me an [E-Mail](mailto:[email protected])
+
+## contributing
+all contributions are welcome! Don't hesitate to ask me if you have any questions.
+
+## current optimizations
+
+
+## code-gen example
+input:
+```c
+fn void strcpy(char* dest, char* src) @export 
+{
+    for (usz i = 0; src[i] != '\0'; i ++)
+        dest[i] = src[i];
+}
+```
+output:
+```asm
+strcpy:
+  xor r11d, r11d
+  .l0:
+  mov r9b, byte [rsi + 1 * r11]
+  test r9b, r9b
+  je .l1
+  mov byte [rdi + 1 * r11], r9b
+  lea r8, [r11 + 1]
+  mov r11, r8
+  jmp .l0
+  .l1:
+  ret
+```