gethex
extern int gethex ANSI((CONST char**, FPI*, Long*, Bigint**, int));
gethex( CONST char **sp, FPI *fpi, Long *exp, Bigint **bp, int sign)
switch((i = gethex(&s, &fpi1, &exp, &bb, sign)) & STRTOG_Retmask) {
irv = gethex(&s, fpi, exp, &rvb, sign);