1 | open BitVectors;; |
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2 | |
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3 | exception Byte7_conversion |
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4 | |
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5 | module Byte7Map = |
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6 | Map.Make (struct type t = byte7 let compare = Pervasives.compare end) |
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7 | module WordMap = |
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8 | Map.Make (struct type t = word let compare = Pervasives.compare end) |
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9 | |
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10 | let int_of_bit = |
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11 | function |
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12 | false -> 0 |
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13 | | true -> 1 |
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14 | |
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15 | let byte7_of_byte b = |
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16 | let bits = to_bits b in |
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17 | match bits with |
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18 | [false;b1;b2;b3;b4;b5;b6;b7] -> mk_byte7 b1 b2 b3 (mk_nibble b4 b5 b6 b7) |
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19 | | _ -> raise Byte7_conversion |
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20 | |
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21 | let add8_with_c (b1 : [`Eight] vect) (b2 : [`Eight] vect) (c : bit) = |
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22 | let n1 = int_of_vect b1 in |
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23 | let n2 = int_of_vect b2 in |
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24 | let c = int_of_bit c in |
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25 | let res = n1 + n2 + c in |
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26 | let ac = n1 mod 16 + n2 mod 16 + c >= 16 in |
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27 | let c6 = n1 mod 128 + n2 mod 128 + c >= 128 in |
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28 | let res,c = res mod 256, res >= 256 in |
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29 | let ov = c <> c6 in |
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30 | vect_of_int res `Eight,c,ac,ov |
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31 | ;; |
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32 | |
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33 | let subb8_with_c (b1 : [`Eight] vect) (b2 : [`Eight] vect) (c : bit) = |
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34 | let n1 = int_of_vect b1 in |
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35 | let n2 = int_of_vect b2 in |
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36 | let c = int_of_bit c in |
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37 | let res = n1 - n2 - c in |
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38 | let ac = n1 mod 16 - n2 mod 16 - c < 0 in |
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39 | let c6 = n1 mod 128 - n2 mod 128 - c < 0 in |
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40 | let res,c = |
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41 | if res >= 0 then res,false |
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42 | else n1 + 256 - n2 - c, true in |
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43 | let ov = c <> c6 in |
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44 | (vect_of_int res `Eight,c,ac,ov) |
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45 | ;; |
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46 | |
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47 | let dec b = |
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48 | let res = int_of_vect b - 1 in |
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49 | if res < 0 then vect_of_int 255 `Eight |
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50 | else vect_of_int res `Eight |
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51 | ;; |
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52 | |
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53 | let inc b = |
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54 | let res = int_of_vect b + 1 in |
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55 | if res > 255 then (vect_of_int 0 `Eight : byte) |
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56 | else (vect_of_int res `Eight : byte) |
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57 | ;; |
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58 | |
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59 | let byte7_of_bit b = |
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60 | [false;false;false;false;false;false;b] |
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61 | ;; |
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62 | |
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63 | let byte_of_byte7 ([b1;b2;b3]::n) = |
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64 | [false;b1;b2;b3]::n |
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65 | ;; |
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