Re: [Caml-list] The tag bit

["Marcin 'Qrczak' Kowalczyk" <qrczak@knm.org.pl>]

W liście z czw, 12-08-2004, godz. 16:31 +0200, Bauer, Christoph napisał:

> why is the tag bit for a int/pointer is stored in and not next to a
> int/pointer.  
> Isn't it possible to divide the memory in blocks of 33 (65 on 64 bit
> machines)  
> Words and the first Word contains all the tag bits?

Value passing would be more complicated.

If you apply a function to 2 arguments, now you pass it 2 words. In your
scheme you would have to find and pass it 2 words plus 2 tag bits in a
3rd register.

Currently a list of ints uses 3 words per element (a block whose first
word is the header, and remaining words are head and tail). With your
scheme it would be 4 words, i.e. 1/3 larger, not 1/32 larger.

-- 
   __("<         Marcin Kowalczyk
   \__/       qrczak@knm.org.pl
    ^^     http://qrnik.knm.org.pl/~qrczak/

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