program Horner's method
// Input:    x, n, a_n, . . ., a_2, a_1, a_0
// Output:   p_n(x) = a_n x^n + . . .  + a_2 x^2 + a_1 x + a_0
// Remarks:  polynomial evaluation via Horner's method
//           Idea:  p_3(x) = ((a_3 * x + a_2) * x + a_1) * x + a_0
//           Example 1 : to convert 765 decimal to hex, enter input
//                       A 2 7 6 5
//           Example 2:  to convert 100 1111 0011 from binary to hex, enter
//                       2 A 1 0 0 1 1 1 1 0 0 1 1
// -----------------------------------------------------------------------------
10: 7C00   R[C] <- 0000                  result c
11: 7101   R[1] <- 0001                  always 1
12: 82FF   read R[2]                     read x
13: 83FF   read R[3]                     read n

14: 84FF   read R[4]                     do { read a_i
15: 1A20   R[A] <- R[2]                  |
16: 1BC0   R[B] <- R[C]                  |    c *= x
17: FF30   R[F] <- pc; goto 30           |  
18: 1CC4   R[C] <- R[C] + R[4]                c += a_i
19: C31C   if (R[3] == 0) goto 1C        |
1A: 2331   R[3] <- R[3] - R[1]           | } while (i-- >= 0)
1B: C014   goto 14                       |

1C: 9CFF   write R[C]                    
1D: 0000   halt                          

function multiply
// Input:                R[A] and R[B] (should be passed by value)
// Return address:       R[F]
// Output:               R[C] = R[A] * R[B]
// Temporary variables:  R[1] = 1

30: 7C00   R[C] <- 0000                  
31: 7101   R[1] <- 0001                  
32: CA36   if (R[A] == 0) goto 36        
33: 1CCB   R[C] <- R[C] + R[B]           
34: 2AA1   R[A] <- R[A] - R[1]           
35: C032   goto 32                       
36: EF00   goto R[F]