Fixnum's in ECL are those integers in the range (-2^29)
to (2^29-1), inclusive. They are represented as immediate data, so no
memory allocation is involved when using fixnum's. Other
integers are bignums. Thus 25 factorial (25!)
15511210043330985984000000
is definitely a bignum in ECL.
Common-Lisp constants related to integers have the following values in ECL.
most-positive-fixnum = 536870911 = 2^29-1
most-negative-fixnum = -536870912 = - 2^29
boole-1 = 3
boole-2 = 5
boole-and = 1
boole-andc1 = 4
boole-andc2 = 2
boole-c1 = 12
boole-c2 = 10
boole-clr = 0
boole-eqv = 9
boole-ior = 7
boole-nand = 14
boole-nor = 8
boole-orc1 = 13
boole-orc2 = 11
boole-set = 15
boole-xor = 6
See Chapter 12 of [see Steele:84] for their meanings.