[LLVMdev] more mips16 puzzles

[Reed Kotler]

On 01/24/2012 06:27 PM, Reed Kotler wrote:
> 1. mips16 instructions (except for move) have a different encoding from
> normal mips32 instructions for two registers.
>
> however in the move register 2 operand instruction, one register takes
> the mips16 encoding and the other the mips32 encoding (so that gives
> mips16 access to the full register set).
>
it just occurred to me that since we are only talking about two cases of 
the move instruction, for registers s0 and s1, i could just invent an 
instruction variant of move which has s0 or s1 implicit
and hardcode the bit pattern for those registers.

moves0 ..
moves1


> how does one deal with multiple encodings of the same register? can you
> change it on an instruction basis? in the case of the move instruction,
> each field has a different encoding.
>
> 2. the extra registers beyond the 8 basic ones in mips16 could be used
> to spill registers (as opposed to using the stack). can llvm do this?
>
> tia.
>
> reed
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev