NAME
    pmod - integral power of an integer modulo a specified integer

SYNOPSIS
    pmod(x, n, md)

TYPES
    x		integer
    n		nonnegative integer
    md		integer

    return	integer

DESCRIPTION
    pmod(x, n, md) returns the integer value of the canonical residue
    of x^n modulo md, where the set of canonical residues is determined
    by md and bits 0, 2, and 4 of config("mod") (other bits are ignored).

    If md is zero, the value is simply x^n.

    For nonzero md, the canonical residues v modulo md are as follows:

		config("mod")	  md > 0	      md < 0

		    0		0 < v < md	   md < v < 0
		    1	      -md < v < 0	    0 < v < -md
		    4		0 < v < md	    0 < v < -md
		    5         -md < v < 0	   md < v < 0
		   16	    -md/2 < v <= md/2   md/2 <= v < -md/2
		   17      -md/2 <= v < md/2     md/2 < v <= -md/2
		   20	    -md/2 < v <= md/2    md/2 < v <= -md/2
		   21	   -md/2 <= v < md/2    md/2 <= v < -md/2

EXAMPLE
    > c = config("mod",0)
    > print pmod(2,3,10), pmod(2,5,10), pmod(2,3,-10), pod(2,5,-10)
    8 2 -2 -8

    > c = config("mod",16)
    > print pmod(2,3,10), pmod(2,5,10), pmod(2,3,-10), pmod(2,5,-10)
    -2 2 -2 2

LIMITS
    none

LIBRARY
    NUMBER *qpowermod(NUMBER *x, NUMBER *n, NUMBER *md)

SEE ALSO
    mod, minv