[Tinycc-devel] Stack based target machine

[Nick Kelsey]

Hi,

I have spent most of the weekend looking through the TCC backend code... 
very impressed... this has the potential to be the ideal solution to the 
problem I have in mind.

TCC already covers the first requirement - a compiler that is practical 
to ship to end-users so they can write their own "scripts" that interact 
with our application.
On the server side TCC can compile to a native x86 machine - perfect.

We also have a number of different embedded platforms... the goal is to 
run a single program on any of these platforms.
Unfortunately they have insufficient resources to run TCC natively, so I 
am looking at compiling to a virtual machine.
Actually a virtual machine solves another problem - memory. We have two 
platforms that have limited core-addressable memory (one has less than 
4k) and a VM would allow us to make use of IO addressable external 
memory by making it c-addressable.

I am leaning towards the idea of a stack based VM to keep things simple 
on the VM side (ie no general purpose registers thus no register 
decoding and addressing required by the host cpu). In reality the 
hardest aspect will be the compiler port so that will dictate the VM 
architecture more than anything else.

I made a few hacks in the backend of TCC but I think I am still missing 
some concepts. In particular the register allocator (gv).

Time to pause and run the concept past you... I am happy to put time 
into coding but would appreciate your thoughts and advice.

BTW - I have written a few VMs in the past, including a cycle-accurate 
simulator of a pipelined processor that was used commercially for VLSI 
testing.

Great product, and I hope to be part of the TCC community.

Nick