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Re: Reload problems with only one base reg for "base + offset" addressing mode


Hi Denis,

I read the "out_movqi_r_mr" code of the AVR port. I see that following
exception are

handled:

1. "REG_X+offset", which is not supported by AVR.
2. "REGY+offset", with offset larger than 63, which is not supported by AVR.

Seems reload can not handle the targets that has some base regs are
offsetable, and some can't.

I will follow your method to handle my port.

Thanks!

2010/8/1 Denis Chertykov <chertykov@gmail.com>:
> 2010/7/31 redriver jiang <jiang.redriver@gmail.com>:
>> Hi,
>>
>> Seems there are still some exceptions.
>>
>> During my testing, the compiler complains:
>>
>> ./os_core.c: In function 'OS_EventTaskWait':
>> ./os_core.c:747: error: unable to find a register to spill in class
>> 'POINTER_REGS'
>> ./os_core.c:747: error: this is the insn:
>> (insn 7 6 8 2 ./os_core.c:739 (set (mem/s/f:HI (plus:HI (reg/f:HI 16
>> R16 [orig:39 OSTCBCur.39 ] [39])
>> ? ? ? ? ? ? ? ?(const_int 13 [0xd])) [11 <variable>.OSTCBEventPtr+0 S2 A8])
>> ? ? ? ?(reg/v/f:HI 2 R2 [orig:40 pevent ] [40])) 48 {*movhi} (nil))
>> ./os_core.c:747: confused by earlier errors, bailing out
>>
>>
>> I guess that it is caused by that there is only one register "R18" in
>> "POINTER_REGS" class.
>>
>> I have changed "LEGITIMIZE_RELOAD_ADDRESS" several times, but still can't work.
>>
>> Do I miss some "macro" definition?
>>
>> Could someone give some direction?
>
> I have a lot of experiments with reloading memory addresses while I
> debug AVR port.
> Finally I have emulated memory addressing with infinite displacement.
>
> Look carefully at avr.c: out_movhi_r_mr
>
> Denis.
>


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