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gforth mmap - can't connect?

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I want to connect support tools for Forth chips like the 
b16 and j1 to my development tools, so that I can 
interactively write code and debug on a simulation of the 
hardware. The tools can the be later connected to the 
FPGA hardware to continue testing at higher speed. 

Small FPGA boards often include a USB comm port for debug, 
so there is no problem connecting tools to real chip, but 
in order to connect up for simulation I need a byte-wide 
bi-directional pipe. To make this easy to port to Windows 
I chose to implement this myself using mmap. 

Getting this working at the chip tools end, in Python, was 
not too difficult, but I cannot seem to get it connecting 
in gforth.  The mmap'd file has only one writer. 


This is the read end setup in Python:

import os
fd_in = os.open('/home/jan/tmp/mmaptest', os.O_RDONLY)
buf = mmap.mmap(fd_in, mmap.PAGESIZE, mmap.MAP_SHARED, mmap.PROT_READ)


This is my gforth read setup:

include mmap_0.7.9.fs
s" /home/jan/tmp/mmaptest"  r/o open-file throw  Value fd_in
here >pagealign here - allot 
here pagesize allot  constant buf
\ buf pagesize PROT_READ MAP_SHARED fd_in  off  mmap      
\ buf pagesize PROT_READ MAP_SHARED fd_in  -1   mmap      
  buf pagesize PROT_READ MAP_SHARED fd_in   0   mmap      

I do not know what 'iff' is, and having looked at mmap docs 
for C still can't guess. Or perhaps my problem is elsewhere?  
I'm not seeing any errors, but buff remains empty, while I 
can see another receiver working correctly. 


The gforth version is Gforth 0.7.0, running under ubuntu. 
Any ideas, updated source or docs, would be appreciated. 


Jan Coombs
-- 
email valid, else fix dots and hyphen
jan4clf2014@murrayhyphenmicroftdotcodotuk

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gforth mmap - can't connect? Jan Coombs <Jan-54 <jenfhaomndgfwutc@murmic.plus.com>> - 2015-04-03 12:07 +0100
  Re: gforth mmap - can't connect? anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2015-04-03 12:03 +0000

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