LUA_PACK_VALUE setXvalue side effect order fix

[szakharchenko]

No description provided.

[bogdanm]

Hi,

Is this meant to fix #69?

Thanks,
Bogdan

[szakharchenko]

No, this is meant to make the two implementations (LUA_PACK_VALUE/!LUA_PACK_VALUE) agree. Vanilla Lua 5.1.4 shouldn't care about the side effect order in set*macros. Seems like the emergency GC patch, or some other patch in eLua, breaks this. Otherwise, why would it bother to reorder the side effects, e.g:

--- a/src/lobject.h
+++ b/src/lobject.h

...

#define setnvalue(obj,x) \
-{ TValue *i_o=(obj); i_o->value.n=(x); i_o->tt=LUA_TNUMBER; }
+{ lua_Number i_x = (x); TValue *i_o=(obj); i_o->value.n=i_x; i_o->tt=LUA_TNUMBER; }

However, the NaN value packing patch is based on the old version of the same code, which now (thanks to other patches) works incorrectly, and needs to be adjusted to match the EGC patch behavior.

When I asked about this on the list, Roberto replied it would be better to use proper temporary variables for this. See the emails for how to reproduce the issue I saw. I may create a proper issue if/when I have time if you need it.

[bogdanm]

Thanks a lot for the fix!