[fpc-pascal] Free Pascal Support for ARM Architecture

[Jonas Maebe]

On 08 Dec 2008, at 00:33, Prince Riley wrote:

> On Sun, Dec 7, 2008 at 4:53 PM, Jonas Maebe  
> <jonas.maebe at elis.ugent.be>wrote:
>
>> On 07 Dec 2008, at 23:01, Prince Riley wrote:
>>
>> "FPC does not specify any particular sub-architecture to the  
>> assembler."
>> was not an opinion or a guess, but a fact. What sub-architecture  
>> the GNU
>> assembler picks in that case (i.e., by default) was the guess.
>>
> My point is saying 'guess' was not to discredit your statement about  
> what
> the FP compiler does, rather to say that no one seems to know  
> exactly what
> ARM option FP sends to the GNU Assembler and what that option value  
> actually
> is.

I don't understand how the following are not in contradiction:
a) "FPC does not specify any particular sub-architecture to the  
assembler." (me)
b) "no one seems to know exactly what ARM option FP sends to the GNU  
Assembler" (you)

The answer is still "FPC passes no ARM sub-architecture option to the  
assembler."

> Reading the GNU as manual, the arch parameter value needs to be set  
> to one
> of several values. It can also specify generic ARM architecture, but  
> that
> choice in addition to being imprecise, could result in code that  
> either is
> not optimized for the target ARM processor, or fail to execute as  
> expected.

It will at most cause the assembler to reject opcodes for particular  
ARM sub-architectures that do not exist in the default sub- 
architecture (which without a doubt is a generic and common ARM  
variant). Crashes only occur if you tell the assembler to accept e.g.  
ARMv6 opcodes, and you genere such opcodes, and then you try to run  
the program on an ARMv4 cpu. I'm not aware of any optimisations that  
the assembler can perform for different ARM architectures (except for  
some small THUMB things, but FPC doesn't generate THUMB code).


Jonas