[Vm-dev] intAt from sqMemoryAccess.h does not extend sign

Nicolas Cellier nicolas.cellier.aka.nice at gmail.com
Tue Nov 8 02:29:05 UTC 2016

In this code:

  static inline sqInt intAtPointer(char *ptr)   { return
(sqInt)(*((unsigned int *)ptr)); }
  static inline sqInt intAtPointerput(char *ptr, int val)  { return
(sqInt)(*((unsigned int *)ptr)= val); }

the usage of unsigned int is questionable...
It means that intAt and long32At won't perform sign extension in 64bits
Spur VM.
Since it returns a signed result (sqInt), that's troubling.

The sole real sender of intAt seems to be primitiveIntegerAt: which fails
for this reason on 64bits spur when fed with negative integers.

For long32At, it's difficult to analyze: many senders!

IMO, if we don't want a signed quantity, we should better write
unsignedLong32At (or use lowcode uint32AtPointer which answers a 32 bits
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