The C compiler being used with the Rhino is HiTech's x86 cross compiler. It compiles ANSI C and also includes a scaled down version of a Microsoft style macro assembler. All of the code that has been developed for the Rhino up to when the HiTech compiler was purchased was written using turbo assembler. Because the HiTech assembler supports only a subset of the features offered by turbo assembler all of the assembly code already written for the Rhino needs to be rewritten using HiTech's assembler or the C compiler. Also, the compiler expects to have full control over the memory space so mixing the turbo assembler code and the HiTech code has proven to be very difficult.