[PicForth] Large amounts of text seem to cause PicForth to generate bad code - updated

[Alex Holden]

I've made some progress in narrowing this bug down. The problem seems to 
be that the yield word in multitasker.fs generates bad code once the 
amount of program memory in use gets above 2K. I think it's probably 
just missing out the bank selects but I really don't understand how 
multitasker.fs works so I'm not sure how to fix it. The large amounts of 
text thing was a red herring- I believe an equal amount of instruction 
code would have caused the same problem to appear.

Here's an example task:

task : alarm begin [char] a emit yield again ;

And here's the generated code:

         ; name: alarm
         ; max return-stack depth: 3
0x07B2  3061    movlw   0x61
0x07B3  20BB    call    0x0BB   ; emit (rs depth: 2)
0x07B4  3007    movlw   0x07
0x07B5  00BF    movwf   0x3F
0x07B6  30B8    movlw   0xB8
0x07B7  2927    goto    0x127   ; flash-write + 0x001
0x07B8  2FB2    goto    0x7B2   ; alarm (rs depth: 3)

In fact 0x127 is not flash-write + 0x001 (it's in the middle of a word 
called /mod) and it's not part of the code generated by 'multitasker' - 
that is at around 0x927 ie. 0x800 (2K) higher than the generated address.

-- 
------------ Alex Holden - http://www.linuxhacker.org ------------
If it doesn't work, you're not hitting it with a big enough hammer