[MUD-Dev] Re: Bruce Sterling on Virtual Community goals

Jon A. Lambert jlsysinc at ix.netcom.com
Thu Oct 22 20:24:33 New Zealand Daylight Time 1998


On 21 Oct 98, Chris Gray wrote:
> [Jon A. Lambert:]
> 
>  >IIRC, Java makes use of 4 psuedo-registers in addition to a stack.
> 
> Nitpick time. I've read the JVM book, and just went and looked. All
> I could find was an SP and a PC per thread. Nothing else. Given
> implementations might find it useful to have a frame pointer or
> perhaps a pointer to the constant pool.
> 
> In my byte-code I added a frame pointer. That was really only to make
> the disassemblies easier to read, if I remember correctly. You can
> always address locals and parameters relative to the SP, by having
> the code generator keep track of changing stack height.
> 

Program counter, Optop, Frame and Vars are the ones listed in
the book I've been reading, QUE books "Using Java 1.1".
It also claims the operand stack is FIFO.  I thought this was odd.
Each method gets it's own stack frame.  Perhaps this is peculiar
to Microsoft's or Symantec's VM.  The book is not really clear on
whose implementation is being referenced.   And I don't know if 
it's authoritative, it may well be misleading.  
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