Re: Porting binutils to mips r5900 (ie Playstation2 EE cpu)

[Thiemo Seufer <ths at networkno dot de>]

Julien Etienne wrote:
> Hello,
> 
> For sometimes I have been using an unofficial toolchain for the mips
> r5900 cpu used in the playstation 2.
> I would like to update the toolchain to fit it in the official
> binutils tree. I will not start from the scratch since the existing
> patch already works, but I would like to modify it according to your
> requirements.
> 
> >From the previous mails on this list about the r5900, I have
> understood that it should be implemented by starting from a r1000

ITYM R3000 here, not r1000.

> basis. It is more close to the r3000, but it lacks r3000 instructions
> and adds new ones.

I wasn't aware it lacks R3000 instructions. Could you check if that's
really true?

AFAIR it is R4000 like, but misses ll/sc/lld/scd and double FP
instructions. The atomic operations are required for MIPS-II and above,
so MIPS-I (with R3000 as a model of it) is the lowest common denominator.

> If you have any recommendations, or if anyone on the list is already
> working on it, do not hesitate to leave me a message.

Define it as a MIPS-I CPU, and add the subset with higher MIPS ISA
variants as well as the R5900 special instructions as R5900 specific.

Most of that will go in in opcodes/mips-opc.c and include/opcode/mips.h.
The R3900 needed something similiar in libopcodes, use it as an example.


Thiemo