1 structure ROOT = |
|
2 struct |
|
3 |
|
4 structure Integer = |
|
5 struct |
|
6 |
|
7 datatype bit = B0 | B1; |
|
8 |
|
9 datatype int = Pls | Min | Bit of int * bit | Number_of_int of int; |
|
10 |
|
11 fun pred (Bit (k, B0)) = Bit (pred k, B1) |
|
12 | pred (Bit (k, B1)) = Bit (k, B0) |
|
13 | pred Min = Bit (Min, B0) |
|
14 | pred Pls = Min; |
|
15 |
|
16 fun succ (Bit (k, B0)) = Bit (k, B1) |
|
17 | succ (Bit (k, B1)) = Bit (succ k, B0) |
|
18 | succ Min = Pls |
|
19 | succ Pls = Bit (Pls, B1); |
|
20 |
|
21 fun plus_int (Number_of_int v) (Number_of_int w) = |
|
22 Number_of_int (plus_int v w) |
|
23 | plus_int k Min = pred k |
|
24 | plus_int k Pls = k |
|
25 | plus_int (Bit (k, B1)) (Bit (l, B1)) = Bit (plus_int k (succ l), B0) |
|
26 | plus_int (Bit (k, B1)) (Bit (l, B0)) = Bit (plus_int k l, B1) |
|
27 | plus_int (Bit (k, B0)) (Bit (l, b)) = Bit (plus_int k l, b) |
|
28 | plus_int Min k = pred k |
|
29 | plus_int Pls k = k; |
|
30 |
|
31 fun uminus_int (Number_of_int w) = Number_of_int (uminus_int w) |
|
32 | uminus_int (Bit (k, B0)) = Bit (uminus_int k, B0) |
|
33 | uminus_int (Bit (k, B1)) = Bit (pred (uminus_int k), B1) |
|
34 | uminus_int Min = Bit (Pls, B1) |
|
35 | uminus_int Pls = Pls; |
|
36 |
|
37 fun times_int (Number_of_int v) (Number_of_int w) = |
|
38 Number_of_int (times_int v w) |
|
39 | times_int (Bit (k, B0)) l = Bit (times_int k l, B0) |
|
40 | times_int (Bit (k, B1)) l = plus_int (Bit (times_int k l, B0)) l |
|
41 | times_int Min k = uminus_int k |
|
42 | times_int Pls w = Pls; |
|
43 |
|
44 end; (*struct Integer*) |
|
45 |
|
46 structure Codegen = |
|
47 struct |
|
48 |
|
49 fun double_inc k = |
|
50 Integer.plus_int |
|
51 (Integer.times_int |
|
52 (Integer.Number_of_int |
|
53 (Integer.Bit (Integer.Bit (Integer.Pls, Integer.B1), Integer.B0))) |
|
54 k) |
|
55 (Integer.Number_of_int (Integer.Bit (Integer.Pls, Integer.B1))); |
|
56 |
|
57 end; (*struct Codegen*) |
|
58 |
|
59 end; (*struct ROOT*) |
|