SCIENTIFIC CALCULATOR

摘要

1476954 Calculators HEWLETT-PACKARD CO 30 April 1974 [29 May 1973] 46149/76 Divided out of 1476951 Heading G4A An electronic calculator for calculating the factorial of a positive number entered into the calculator includes a first storage register for initially storing the entered number and for subsequently storing decremented values thereof, a second storage register, having a first field includings 1s and 10s digit positions for storing a preselected constant number in the 10s position and a second field initially storing zero, and a third storage register coupled to the first and second storage registers, having a first field including 1s and 10s digit positions for storing successively modified values of the entered value and a second field initially storing the entered number, a processing unit coupled to the three registers repetitively decrementing the entered number until it is zero and, following each such decrementing, transferring the contents of the second field of the third register to the second field of the second register and zeroing the second field of the third register, transferring each decremented value of the entered number to the first field of the third register, adding the first fields of the second and third registers and storing the result in the first field of the third register, adding the second fields of the second and third register and storing the result in the second field of the third register until the 10s digit position of the first field of the third register equals a first value (as described, zero) thereupon left shifting the numbers stored in the first and second fields of the third register whereupon a second series of additions of the contents of the first and second fields of the second and third registers is performed until the 10s position of the first field of the third register equals the first value, this process being repeated until the contents of the first register and the first field of the third register are both zero. Specifications 1,476,951, 1,476,952 and 1,476,954 are referred to.