ISORTD - descending signed integer sort.

call isortd(array, nrec, lrs, key1 [, key2, ... keyN])

array: is the name of the array to be sorted.
nrec: is the number of elements (or "records") to be sorted.
lrs: is the number of words in each element.
key1 [, key2 ... keyN]: are the keys to sort on. Each key specifies a word (0 <= key < lrs) within an element to sort on. The keys are specified in decreasing order of importance.

ISORTD sorts an array of things in descending order. Each key is sorted in signed integer (arithmetic compare) order.