[fpc-devel] How do I find out which registers are actually used in an interrupt procedure and need to get pushed

[Michael Ring]

This tip worked just fine, I was too blind to see how this works .....

Thank you Jonas!

Michael

Am 30.06.16 um 15:47 schrieb Jonas Maebe:
>
> Michael Ring wrote on Thu, 30 Jun 2016:
>
>> So far I understood the fpc code that registers s0-s7 are 
>> automagically flagged when used as those are the registers that must 
>> be saved in the context of a standard procedure/function call.
>>
>> Same does apply for some of the Floating Point Registers.
>>
>> But when I look at the list of registers to be saved the registers 
>> like $v0 and $v1 are not included, but usually used.
>
> You'll probably want to modify 
> tcpuparamanager.get_volatile_registers_(int/fpu) in 
> compiler/mips/cpupara.pas based on the passed calloption.
>
> Volatile registers are registers that do not need to be saved by the 
> callee according to the ABI, even if they are modified by the callee. 
> For interrupt routines, you'll probably want to return an empty set 
> there.
>
>
> Jonas
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