[VM] CompiledMethod header format?
Bob Arning
arning at charm.net
Sat Dec 30 02:54:34 UTC 2000
On Fri, 29 Dec 2000 20:22:48 -0500 (EST) "Matthew S. Davis" <mdavis at cse.psu.edu> wrote:
> I've determined the following header format from the Interpreter
>methods:
>
>bit 0 : constant 1 to indicate SmallInteger
>bits 1-9 : primitive index
>bits 10-17 : literal count
>bit 18 : not used?
>bits 19-25 : temporary count
>bits 25-28 : argument count
>bits 29-31 : primitive index
>
> Could someone please explain why bit 25 is shared between two
>fields? I'm not clear why this is the case. Should the temporary count
>really be in bit positions 18-24? If so, it does not look like they are.
Matthew,
Temporary count is definitely 6 bits in the header. Where did you see an indication that it was 7?
And the bit you have marked as unused is the Large/Small context flag.
Cheers,
Bob
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