Using a Restrained C-language to define processor and memory

As introduced in chapter 2, we describe, as a target language, the processor and the memory models, using a subset of the standard C-language, called Restrained-C or . This provides us with a kind of ``virtual target machine'' for our specifications.

Therefore, the restrained C-language will be used for two purposes:

1. Define memory-objects, i.e. pieces of memory which contain some data on which we want to do apply pieces of code. Very restrictive aspects will be introduced, since we want:
   • To avoid any erroneous addressing, i.e. to able to demonstrate at compilation time that no memory violation or overflow wil occur.
   • To be able to compute the memory addressing time.
2. Define pieces of codes, i.e. certain sequences of instructions which modifies the value of a memory object. Similarly, very restrictive properties are required, since we want: :
   • To avoid any infinite loops or spurious jumps in the code, and to calculate the computation time, in function of the input data.
   • To be able to predict the semantic of the action performed by the piece of code.

However, it is important to note that we are not going to analyse what, in the C-language, can fit with the previous requirements and what cannot, but simply utilize a minimal set of C-features to define the memory structure and generate pieces of code.

Here the presentation of the set of C-features to be used in the ReViMoGe system to define the memory structure and to generate pieces of code.