Using Cache As Ram for K8

Bari Ari bari at onelabs.com
Thu Jun 24 17:48:00 CEST 2004


Eric W. Biederman wrote:

>>Eric,
>>What is the "effective" or "equalvalent" stack size of ROMCC ?
>>Is 448 bytes of stack adquant for ROMCC "linted" code in general ?
> 
> 
> 8 (gpr) + 8 (mmx) + 8 (sse) registers each 4 bytes long = 96 bytes.
> Looking at the hdama configuration my max inline depth is 14
> procedures so that likely totals to another 14 *4 = 56 bytes in
> return addresses.  So 448 bytes would be a small improvement.  
> 
> Note generally I have noticed romcc compiled does not even use all of
> the registers... 
> 
For comparison when using U-Boot for PPC:

"Note: on PPC, we could use a static initializer (since the address of 
the global data structure is known at compile time), but it turned out 
that reserving a register results in somewhat smaller code - although 
the code savings are not that big (on average for all boards 752 bytes 
for the whole U-Boot image, 624 text + 127 data)."

-Bari






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