Re: [SOLVED] Re: and/or missbehaviour in embedded lua 5.1

[Kein-Hong Man <mkh@...>]

Mike Pall wrote:
> [snip]
> Ok, this is a serious bug in Lua 5.1. It's only visible if
> sizeof(int)*2 < sizeof(lua_Number). I.e. it probably only affects
> 16 bit CPUs with lua_Number defined as a double. But the original
> assignments depend on a side-effect (full overlap) not guaranteed
> by the standard (even on 32/64 bit CPUs).
>
> But the fix bears the question: is union assignment part of C89?

Is the union necessary at all? The bunch of expdesc in the 
front-end doesn't look like it is a big memory hog. On x86, doing 
without a union increases the structure size from 20 bytes to 28 
bytes. I don't think this will eat up a lot more memory...

In fact, all the expdesc declarations look like they are local to 
functions and are allocated on the stack. Once the source is 
compiled, the memory used by expdesc structures ceases to be a 
problem...

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia