readme stuff, pls check if outdated

BUILD_WITH_CMAKE.md

@@ -73,7 +73,7 @@ The romeo-obsw binary can now be found in the `build_z7` directory. The next ste
 
 ## Linux
 
-The obsw can also be compiled and run on linux using the gcc-posix port of FreeRTOS.
+The obsw can also be compiled and run on linux using the `gcc-posix` port of FreeRTOS.
 
 ### build
 

README.md

@@ -43,6 +43,22 @@ The current working steps are:
 Consider using Docker or setting up a local compile toolchain.
 Please refer to [BUILD_WITH_DOCKER.md](./BUILD_WITH_DOCKER.md) or [BUILD_WITH_CMAKE.md](./BUILD_WITH_CMAKE.md).
 
+### Compiling Annotations
+Bare metal rust on the Zynq requires the use of C-libraries, which affects the compilation. 
+The current setup includes `cmake` which calls `cargo`to compile the rust `mission` and `framework` creates as `static libraries`. 
+Then, `gcc` is used to link those two libraries , the `Xilinx Board Support Packages (BSP)` (incl. all hardware drivers), and supplier libraries in the final binary.
+
+The canocial compiler is debian bookkworm's `arm-none-eabi-gcc 12.2` using `newlib 3.3.0`.
+
+The **minimum** set of **compiler** (not linker) **flags** (as used by Xilinx to build the First Stage Bootloader (FSBL)) are
++ hardware (HW) type: `-mcpu=cortex-a9 -mfpu=vfpv3 -mfloat-abi=hard`
++ function and data sections, to be able to garbage-collect unused code: `-ffunction-sections -fdata-sections`
++ optimization for release: `-O2`
+
+Link Time Optimization (LTO) TBD
+<!--Currently LTO is not enabled, as it might break linkage with the static STR library, TBC with STR supplier.
+
+... to be completed ... TODO PAUL-->
 ## How to debug on hardware?
 
 Please refer to [DEBUG_ON_ZEDBOARD.md](./DEBUG_ON_ZEDBOARD.md)