Re: [Lightning] Runtime assembler in C++

[Paolo Bonzini]

Pippijn van Steenhoven wrote:
> I do not yet
> have differently sized types. Everything that is an immediate is passed
> as int32_t. This might cause breakage on 64 bit platforms but I don't
> know how to do the differently sized types, yet. I do not use the macros
> directly, anymore. Instead, for each mnemonic, I use a C++ function. This
> has produced many error messages. I fixed some, but I don't know whether
> the fixes are correct. As far as I can remember (unfortunately I didn't
> document my changes, so I'll probably redo them with documentation), I
> added an _s32P macro which was used but missing and the LEAQmr
> instruction for x86_64 which looks like this:
>
>   #define LEAQmr(MD, MB, MI, MS, RD)      (_REXQmr(MB, MI, RD),           
> _OO_r_X         (0x8d                ,_r8(RD)           ,MD,MB,MI,MS            
> ))

These two I will look at.

>  There is a long list of instructions that do not work on
> x86_64 because they do not exist or some other macro is being used
> incorrectly. I am aware that x86_64 support is new, but even on i386-32,
> many instructions do not exist. If you are interested, I can generate
> this list.

Yes, thanks!  This can indeed be helpful, if only to stress test the 
back-ends.

> By the way, is there any reason to have more than one "variable"?
> Variables are integers returned by an instruction. Currently, the only
> instructions that do this in my assembler are the lightning arg_*
> instructions.

Yes, I don't remember other instructions that return arbitrary integers. 
 I don't understand your question exactly, but: 1) there can be >1 
argument to a function; 2) you could use fixed names like $1, $2, $3 -- 
but then, checking that these fixed names were actually defined is 
almost as complicated as keeping the map<>.

Paolo