| 
0
 | 
     1  | 
(*  Title: 	ZF/bin
  | 
| 
 | 
     2  | 
    ID:         $Id$
  | 
| 
 | 
     3  | 
    Author: 	Lawrence C Paulson, Cambridge University Computer Laboratory
  | 
| 
 | 
     4  | 
    Copyright   1993  University of Cambridge
  | 
| 
 | 
     5  | 
  | 
| 
 | 
     6  | 
Arithmetic on binary integers.
  | 
| 
 | 
     7  | 
*)
  | 
| 
 | 
     8  | 
  | 
| 
 | 
     9  | 
BinFn = Integ + Bin +
  | 
| 
 | 
    10  | 
consts
  | 
| 
 | 
    11  | 
  bin_rec          :: "[i, i, i, [i,i,i]=>i] => i"
  | 
| 
 | 
    12  | 
  integ_of_bin     :: "i=>i"
  | 
| 
 | 
    13  | 
  bin_succ         :: "i=>i"
  | 
| 
 | 
    14  | 
  bin_pred         :: "i=>i"
  | 
| 
 | 
    15  | 
  bin_minus        :: "i=>i"
  | 
| 
 | 
    16  | 
  bin_add,bin_mult :: "[i,i]=>i"
  | 
| 
 | 
    17  | 
  | 
| 
 | 
    18  | 
rules
  | 
| 
 | 
    19  | 
  | 
| 
 | 
    20  | 
  bin_rec_def
  | 
| 
 | 
    21  | 
      "bin_rec(z,a,b,h) == \
  | 
| 
 | 
    22  | 
\      Vrec(z, %z g. bin_case(a, b, %w x. h(w, x, g`w), z))"
  | 
| 
 | 
    23  | 
  | 
| 
 | 
    24  | 
  integ_of_bin_def 
  | 
| 
 | 
    25  | 
      "integ_of_bin(w) == bin_rec(w, $#0, $~($#1), %w x r. $#x $+ r $+ r)"
  | 
| 
 | 
    26  | 
  | 
| 
 | 
    27  | 
  bin_succ_def
  | 
| 
 | 
    28  | 
      "bin_succ(w0) == bin_rec(w0, Plus$$1, Plus, %w x r. cond(x, r$$0, w$$1))"
  | 
| 
 | 
    29  | 
  | 
| 
 | 
    30  | 
  bin_pred_def
  | 
| 
 | 
    31  | 
      "bin_pred(w0) == \
  | 
| 
 | 
    32  | 
\	bin_rec(w0, Minus, Minus$$0, %w x r. cond(x, w$$0, r$$1))"
  | 
| 
 | 
    33  | 
  | 
| 
 | 
    34  | 
  bin_minus_def
  | 
| 
 | 
    35  | 
      "bin_minus(w0) == \
  | 
| 
 | 
    36  | 
\	bin_rec(w0, Plus, Plus$$1, %w x r. cond(x, bin_pred(r$$0), r$$0))"
  | 
| 
 | 
    37  | 
  | 
| 
 | 
    38  | 
  bin_add_def
  | 
| 
 | 
    39  | 
      "bin_add(v0,w0) == 			\
  | 
| 
 | 
    40  | 
\       bin_rec(v0, 				\
  | 
| 
 | 
    41  | 
\         lam w:bin. w,       		\
  | 
| 
 | 
    42  | 
\         lam w:bin. bin_pred(w),	\
  | 
| 
 | 
    43  | 
\         %v x r. lam w1:bin. 		\
  | 
| 
 | 
    44  | 
\	           bin_rec(w1, v$$x, bin_pred(v$$x),	\
  | 
| 
 | 
    45  | 
\		     %w y s. (r`cond(x and y, bin_succ(w), w)) \
  | 
| 
 | 
    46  | 
\		             $$ (x xor y)))    ` w0"
  | 
| 
 | 
    47  | 
  | 
| 
 | 
    48  | 
  bin_mult_def
  | 
| 
 | 
    49  | 
      "bin_mult(v0,w) == 			\
  | 
| 
 | 
    50  | 
\       bin_rec(v0, Plus, bin_minus(w),		\
  | 
| 
 | 
    51  | 
\         %v x r. cond(x, bin_add(r$$0,w), r$$0))"
  | 
| 
 | 
    52  | 
end
  |