[PicForth] question - recycling GPR variables

[David McNab]

Hi,

In writing another PicForth driver, I'm in a situation of having to 
handle about 8 values simultaneously.

Having them all on the stack is out of the question. Yes, there's now a 
'pick' word, but there are no corresponding words to support storing 
back to location n in the stack, nor is there anything like rot, -rot, 
roll or -roll. Also, PIC architecture forces inefficiencies when 
addressing variable locations.

So my only option is to allocate variables for these values, and operate 
directly on the variables.

With other HLLs such as C, the compiler avoids a data stack altogether, 
and allocates cells in absolute GPR locations instead. It then uses 
heuristics to analyse the call tree and recycle these GPRs wherever 
possible.

Is there anything like this in PicForth? I'm trying to conserve data 
memory, and would prefer not to have 9 GPRs permanently allocated for 
just this one driver alone.

-- 
Cheers
David