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* correct ofset for saving floating point registers + explanation behind

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the calculation (fixes make cycle on ARMHF)

git-svn-id: trunk@25777 -
This commit is contained in:
Jonas Maebe 2013-10-14 12:49:31 +00:00
parent 31a3122b91
commit 5276159e77
1 changed files with 41 additions and 2 deletions
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43
compiler/arm/cpupi.pas
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@ -186,9 +186,48 @@ unit cpupi;
end;
floatsavesize:=align(floatsavesize,max(current_settings.alignment.localalignmin,4));
result:=Align(tg.direction*tg.lasttemp,max(current_settings.alignment.localalignmin,4))+maxpushedparasize+aint(floatsavesize);
floatregstart:=tg.direction*result+maxpushedparasize;
{ Note: in cgcpu "-floatregstart" is subtracted -> reason based on
"adding floatregstart" to avoid double negation
tg.direction=1 -> no framepointer ->
1) save used int registers
2) allocate stacksize (= subtracting result, which is positive,
from the stackpointer)
3) add floatregstart to the stackpointer to get the offset where
to store the floating point registers (-> floatregstart
should be positive)
4) store the floating point registers from this offset with IA
(i.e., this offset and higher addresses -> offset should
point to lower end of area)
-> newsp+(result) points to lower end of saved int registers area
-> newsp+(result-floatsavesize) points to lower end of float reg
saving area
tg.direction=-1 -> with framepointer ->
1) save stack pointer in framepointer
2) save used int registers using stackpointer
3) allocate stacksize (= subtracting result, which is positive,
from the stack pointer)
4) add floatregstart" to the framepointer to get the offset
where to store the floating point registers (-> floatregstart
should be negative)
5) store the floating point registers from this offset with IA
(i.e., this offset and higher addresses -> offset should
point to lower end of area)
o in this case, firsttemp starts right after the saved int
registers area (or a bit further, because it's calculated for
the worst-case scenario, when all non-volative integer
registers have to be saved) -> we store the floating point
registers between the last temp and the parameter pushing area
-> fp+(-result) points to the top of the stack (= end of
parameter pushing area)
-> fp+(-result+maxpushedparasize) points to the start of the
parameter pushing area = lower end of float reg saving area
}
if tg.direction=1 then
dec(floatregstart,floatsavesize);
floatregstart:=result-aint(floatsavesize)
else
floatregstart:=-result+maxpushedparasize;
end;
end;