Threaded Mode | Linear Mode

Eddie W. Shore · (This post was last modified: 06-15-2017 01:30 PM by Gene.)

The program solves for x in the equation:

A * x = B mod N

Examples:

4 * x = 6 mod 7
A = 4, B = 6, N = 7
Solution: 5

5 * x = 3 mod 17
A = 5, B = 3, N = 17
Solution: 4

11 * x = 3 mod 16
A = 11, B = 3, N = 16
Solution: 9

Main Routine: Label C
Subroutines: D, E
No pre-storing any variables required. If there is no solution, an error is produced.
To Run: XEQ C

Code:

C01 LBL C

C02 INPUT A

C03 INPUT B

C04 INPUT N

C05 1

C06 STO I

D01 LBL D

D02 RCL I

D03 RCL × A

D04 RCL - B

D05 RCL ÷ N

D06 FP

D07 x ≠ 0?

D08 GTO E

D09 RCL I

D010 RTN

E01 LBL E

E02 1

E03 STO + I

E04 RCL I

E05 RCL N

E06 x > y?

E07 GTO D

E08 0

E09 1/x

E10 RTN