DEFCFUN and unsigned-long-long behaving badly on 64-bit Allegro CL

[Luís Oliveira]

Bug report sent to Franz.

(in-package :cl-user)

#||

#include <limits.h>

unsigned long long ullong(unsigned long long n)
{
    printf("ullong(%llu)\n", n);
    return n == ULLONG_MAX ? n : 42;
}

||#

(ff:def-foreign-call (ullong "ullong")
    ((n :unsigned-nat (unsigned-byte 64)))
  :returning (:unsigned-nat (unsigned-byte 64))
  :call-direct t ; setting this to nil fixes the symptoms.
  :arg-checking nil
  :strings-convert nil)

(defun test-ullong ()
  (ullong (1- (expt 2 64))))

;; CL-USER> (ullong (1- (expt 2 64)))
;; ullong(18446744073709551615)
;; 18446744073709551615 ; OK
;;
;; But when :call-direct kicks in:
;; CL-USER> (test-ullong)
;; ullong(18446744073709551615) ; argument was fine
;; -1 ; but return value is wrong