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Re: PATCH:[darwin] fix load of a misaligned double word


David:

Thanks, this fixes the performance degradation I was seeing (to within
benchmark measurement error).

I'll have to think a bit more about how to implement data-tagged languages like
Lisp or Scheme on PPC64.  A tag of 0 is too useful for fixnums to use it
for anything else, and if one uses two tag bits, then tags of 1, 2, or 3 for
memory-allocated objects will require an extra addition to clear the tag.  So
it appears that for a 64-bit Scheme/Lisp on PPC64 one should use at least
three tag bits with a tag value of 4 for memory-allocated objects.

Brad


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