And so, finally, after all that setup, some code to read PGM files and how to make use of it. Next stage will be writing some files!
As always, the code can be found on github
Musings, parallel thoughts
Musings, parallel thoughts
And so, finally, after all that setup, some code to read PGM files and how to make use of it. Next stage will be writing some files!
As always, the code can be found on github
As I understand it, it works because it’s all enclosed in a bigger loop:
allpixels : loop
readline(pgmfile, l);
exit when l = null;
exit when l'length = 0;
loop in question-->
loop
read(l, int, good);
exit when not good;
ret(x, y) := int;
exit allpixels when x = width-1 and y = height-1;
x := x + 1;
if x >= width then
x := 0;
y := y + 1;
end if;
end loop;
end loop allpixels;
Now that I think of it, this confusion may be due to the format of my pgm files. Every pixel value is on a new line, as exported by Gimp. Example:
P2
# CREATOR: GIMP PNM Filter Version 1.1
450 375
255
119
120
...
That’s why the read() in question reads 1 character per line and then throws the error. I have run your testbench with the changes and it works the same. I’m using the Isim that comes with ISE 12.1 (M.53d)
I’m not sure that’s a valid fix in general (removing the loop and the exit) – it works fine for one number per line, but shouldn’t work when there’s more than one number per line. That may be a failing of my testcases!
I think the root-cause of the problem is really just that Isim is whinging a lot. I’ll see if I can replicate it here and come up with a better fix.