Dynabook hw cost

Daniel Lanovaz daniel at precedia.com
Fri May 25 00:36:43 UTC 2007


 >Oddly enough none of the sparc tag stuff turned out to help us with
 >that particular code generator; and the register windows stuff caused
 >so much hassle I think it was ignored as much as possible.

Peter (L. Peter Deutsch) created two versions of the
PPS translator for SPARC: one with and one without
the use of register windows.

The register window version was the default in the
shipping product (using the save/restore call-return
instructions). The call delay slot was typically
always utilized.

I was forced to use register windows in PPS's native
language and callback interfaces because that was the
default compiler setting on Sun platforms at the time.

We did not use SPARC's tagged instructions, as we
tagged in the low-order two bits, aligning all objects
on a four byte boundary, thus freeing the two bits.

Daniel



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