[fpc-devel] Questions regarding pushing more onto assembler

[Florian Klaempfl]

Peter Vreman wrote:

>>I have some questions regarding porting of FPC to another machine type.
>>One of the things I am considering doing is the "pushing" of more of the
>>code processing onto the assembler, and whether this might be a better
>>idea, or if it was thought about and rejected for some reasons and it
>>might be worth noting if it was thought about.
>>
>>For example, I am thinking that code such as
>>
>>               if  xray = 5 then
>>                    do_something
>>               else
>>                    do_something_else;
>>
>>Where 'do_something' and 'do_something_else' could be one line or a
>>BEGIN / END block.  This could, with use of a good macro assembler, be
>>handled as something like
>>
>>                 IF   XRAY,EQ,F5
>>                        do_something                    ; code as
>>generated
>>                 ELSE
>>                        do_something_else            ; more code
>>                 ENDIF
>>
>>F5             DC     F'5'                                 Constant
>>defined
>>
>>Now, the idea is the IF, ELSE and ENDIF macros will handle the creation
>>of the particular code for testing and such.
>>
>>There are a number of (already written) macros available to do this, and
>>I think it will reduce the complexity of the compiler (at a slight
>>increase in complexity of the generated code via macros) .  I am
>>wondering if there are any thoughts on this idea.
> 
> 
> This is not possible with fpc. The compiler is made to generate the
> instructions itself in a list. See cgobj.pas and cgcpu.pas what is
> required for a new processor.

Preferably arm and sparc because they are the easiest.