Re: gas: additional macro functionality (patch attached)

[Nick Clifton]

Hi Olaf,

> I missed the possibility to reference
> a) the individual invocation count of each macro and b) the previous 
> invocation count for each macro.

Actually this can be done using the current macro features of gas.

> Problem: I need to build a single linked list at assemble time. This is 
> traditionally done with somethink like:
>
>         .set LINK, 0
>
> .macro    HEAD foo, bar
>         ...
>         .word    LINK
>         .set        LINK,.
>         .endm
>
> This does not work with gas assembling msp430 code on a PPC Mac, because
> LINK only gets resoved at relocation time, so all LINK fields are the 
> same :-(

Ah, but that is because you are setting LINK to the value of "." which is the 
location counter which needs to be resolved at link time.  If instead you use a 
static count for the macro then you can achieve the results you want.  Like this:

        .set LINK, 0

  .macro HEAD
        .word  LINK
        .set   LINK, LINK + 1
        .endm

You can also use expressions like "(LINK +1)" and "(LINK - 1)" to get the next 
and previous invocation counts.

Cheers
  Nick