Hello everyone,
I am currenly porting a large project (a fuzzy robot controller/AI system)
consisting of both C and lisp code to run under CMUCL and have encountered
some difficutlies with foreign function calls and the way integers are
handled within CMUCL. I hope someone can help me with this.
The main problem is that in the lisp code is commonly giving arrays of
integers and floats which the C functions return values in. For the floats it
work good to do eg:
C-code:
void loc_update_robot(float pos83],float unc[128]) { .... }
Lisp
(alien:def-alien-routine ("loc_update_robot"
loc_update_robot0) void
(pos (* single-float) :in)
(unc (* single-float) :in))
(defmacro loc_update_robot (pos unc)
`(sys:without-gcing (loc_update_robot0
(system:vector-sap ,pos) (system:vector-sap ,unc))))
And then call the function with global array of floats created using eg:
(defvar *robot-unc* (make-array 128 :element-type 'single-float)))
However, this method doesn't work for integers since the implemention of
integers in CMUCL differs from ordinary C-integers which leads to some realy
strange errors (the 2 lowermost bits are used as type and gc information?)
What is the easiest way of handling arrays of integers. Since the code is
running very often (the control loop cycle is < 100ms) I would prefer if
possible not to do converstions between the lisp and C side. Is it eg.
possible to somehow create and use "normal" 32bit integers in CMUCL?
thankfull for any help you can give =)
/ Mathias Broxvall
