[fpc-pascal] Free Pascal Support for ARM Architecture

Jonas Maebe jonas.maebe at elis.ugent.be
Mon Dec 8 21:17:14 CET 2008


On 08 Dec 2008, at 20:43, Prince Riley wrote:

> What I keep asking here and not getting a precise answer about is what
> specific ARM opcodes does the FP support What is its default ARM
> architecture is the opcode spec based on?

The problem was that you never asked for which ARM architecture FPC  
generates assembler code, but only which ARM sub-architecture  
parameter FPC passes to the GNU assembler. Those are two completely  
separate questions (and unrelated in this case).

By default, FPC generates ARMv4 architecture code. You can also ask  
for ARMv5 and ARMv6 code (using the -Cp command line option, see  
"ppcrossarm -i" for the possible options).

In practice, the only difference at this time is that the prefetch()  
statement is not translated into assembler code unless you target  
ARMv6 (because earlier ARM cpus do not have a prefect assembler  
instruction).

> To be clear ARM5 and ARM7 aren't
> variants, they are RISC family processors to be sure, but they are
> 'different.'

They are variants of the same processor family (just like the i386 and  
the Core2Duo are variants of the same processor family). The fact that  
they are variants does not mean that they support exactly the same  
instruction set.


Jonas



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