1 (* |
|
2 Author: Jeremy Dawson and Gerwin Klein, NICTA |
|
3 |
|
4 contains theorems to do with shifting, rotating, splitting words |
|
5 *) |
|
6 |
|
7 header {* Shifting, Rotating, and Splitting Words *} |
|
8 |
|
9 theory WordShift |
|
10 imports WordBitwise |
|
11 begin |
|
12 |
|
13 subsection "Bit shifting" |
|
14 |
|
15 lemma shiftl1_number [simp] : |
|
16 "shiftl1 (number_of w) = number_of (w BIT bit.B0)" |
|
17 apply (unfold shiftl1_def word_number_of_def) |
|
18 apply (simp add: word_ubin.norm_eq_iff [symmetric] word_ubin.eq_norm |
|
19 del: BIT_simps) |
|
20 apply (subst refl [THEN bintrunc_BIT_I, symmetric]) |
|
21 apply (subst bintrunc_bintrunc_min) |
|
22 apply simp |
|
23 done |
|
24 |
|
25 lemma shiftl1_0 [simp] : "shiftl1 0 = 0" |
|
26 unfolding word_0_no shiftl1_number by auto |
|
27 |
|
28 lemmas shiftl1_def_u = shiftl1_def [folded word_number_of_def] |
|
29 |
|
30 lemma shiftl1_def_s: "shiftl1 w = number_of (sint w BIT bit.B0)" |
|
31 by (rule trans [OF _ shiftl1_number]) simp |
|
32 |
|
33 lemma shiftr1_0 [simp] : "shiftr1 0 = 0" |
|
34 unfolding shiftr1_def |
|
35 by simp (simp add: word_0_wi) |
|
36 |
|
37 lemma sshiftr1_0 [simp] : "sshiftr1 0 = 0" |
|
38 apply (unfold sshiftr1_def) |
|
39 apply simp |
|
40 apply (simp add : word_0_wi) |
|
41 done |
|
42 |
|
43 lemma sshiftr1_n1 [simp] : "sshiftr1 -1 = -1" |
|
44 unfolding sshiftr1_def by auto |
|
45 |
|
46 lemma shiftl_0 [simp] : "(0::'a::len0 word) << n = 0" |
|
47 unfolding shiftl_def by (induct n) auto |
|
48 |
|
49 lemma shiftr_0 [simp] : "(0::'a::len0 word) >> n = 0" |
|
50 unfolding shiftr_def by (induct n) auto |
|
51 |
|
52 lemma sshiftr_0 [simp] : "0 >>> n = 0" |
|
53 unfolding sshiftr_def by (induct n) auto |
|
54 |
|
55 lemma sshiftr_n1 [simp] : "-1 >>> n = -1" |
|
56 unfolding sshiftr_def by (induct n) auto |
|
57 |
|
58 lemma nth_shiftl1: "shiftl1 w !! n = (n < size w & n > 0 & w !! (n - 1))" |
|
59 apply (unfold shiftl1_def word_test_bit_def) |
|
60 apply (simp add: nth_bintr word_ubin.eq_norm word_size) |
|
61 apply (cases n) |
|
62 apply auto |
|
63 done |
|
64 |
|
65 lemma nth_shiftl' [rule_format]: |
|
66 "ALL n. ((w::'a::len0 word) << m) !! n = (n < size w & n >= m & w !! (n - m))" |
|
67 apply (unfold shiftl_def) |
|
68 apply (induct "m") |
|
69 apply (force elim!: test_bit_size) |
|
70 apply (clarsimp simp add : nth_shiftl1 word_size) |
|
71 apply arith |
|
72 done |
|
73 |
|
74 lemmas nth_shiftl = nth_shiftl' [unfolded word_size] |
|
75 |
|
76 lemma nth_shiftr1: "shiftr1 w !! n = w !! Suc n" |
|
77 apply (unfold shiftr1_def word_test_bit_def) |
|
78 apply (simp add: nth_bintr word_ubin.eq_norm) |
|
79 apply safe |
|
80 apply (drule bin_nth.Suc [THEN iffD2, THEN bin_nth_uint_imp]) |
|
81 apply simp |
|
82 done |
|
83 |
|
84 lemma nth_shiftr: |
|
85 "\<And>n. ((w::'a::len0 word) >> m) !! n = w !! (n + m)" |
|
86 apply (unfold shiftr_def) |
|
87 apply (induct "m") |
|
88 apply (auto simp add : nth_shiftr1) |
|
89 done |
|
90 |
|
91 (* see paper page 10, (1), (2), shiftr1_def is of the form of (1), |
|
92 where f (ie bin_rest) takes normal arguments to normal results, |
|
93 thus we get (2) from (1) *) |
|
94 |
|
95 lemma uint_shiftr1: "uint (shiftr1 w) = bin_rest (uint w)" |
|
96 apply (unfold shiftr1_def word_ubin.eq_norm bin_rest_trunc_i) |
|
97 apply (subst bintr_uint [symmetric, OF order_refl]) |
|
98 apply (simp only : bintrunc_bintrunc_l) |
|
99 apply simp |
|
100 done |
|
101 |
|
102 lemma nth_sshiftr1: |
|
103 "sshiftr1 w !! n = (if n = size w - 1 then w !! n else w !! Suc n)" |
|
104 apply (unfold sshiftr1_def word_test_bit_def) |
|
105 apply (simp add: nth_bintr word_ubin.eq_norm |
|
106 bin_nth.Suc [symmetric] word_size |
|
107 del: bin_nth.simps) |
|
108 apply (simp add: nth_bintr uint_sint del : bin_nth.simps) |
|
109 apply (auto simp add: bin_nth_sint) |
|
110 done |
|
111 |
|
112 lemma nth_sshiftr [rule_format] : |
|
113 "ALL n. sshiftr w m !! n = (n < size w & |
|
114 (if n + m >= size w then w !! (size w - 1) else w !! (n + m)))" |
|
115 apply (unfold sshiftr_def) |
|
116 apply (induct_tac "m") |
|
117 apply (simp add: test_bit_bl) |
|
118 apply (clarsimp simp add: nth_sshiftr1 word_size) |
|
119 apply safe |
|
120 apply arith |
|
121 apply arith |
|
122 apply (erule thin_rl) |
|
123 apply (case_tac n) |
|
124 apply safe |
|
125 apply simp |
|
126 apply simp |
|
127 apply (erule thin_rl) |
|
128 apply (case_tac n) |
|
129 apply safe |
|
130 apply simp |
|
131 apply simp |
|
132 apply arith+ |
|
133 done |
|
134 |
|
135 lemma shiftr1_div_2: "uint (shiftr1 w) = uint w div 2" |
|
136 apply (unfold shiftr1_def bin_rest_div) |
|
137 apply (rule word_uint.Abs_inverse) |
|
138 apply (simp add: uints_num pos_imp_zdiv_nonneg_iff) |
|
139 apply (rule xtr7) |
|
140 prefer 2 |
|
141 apply (rule zdiv_le_dividend) |
|
142 apply auto |
|
143 done |
|
144 |
|
145 lemma sshiftr1_div_2: "sint (sshiftr1 w) = sint w div 2" |
|
146 apply (unfold sshiftr1_def bin_rest_div [symmetric]) |
|
147 apply (simp add: word_sbin.eq_norm) |
|
148 apply (rule trans) |
|
149 defer |
|
150 apply (subst word_sbin.norm_Rep [symmetric]) |
|
151 apply (rule refl) |
|
152 apply (subst word_sbin.norm_Rep [symmetric]) |
|
153 apply (unfold One_nat_def) |
|
154 apply (rule sbintrunc_rest) |
|
155 done |
|
156 |
|
157 lemma shiftr_div_2n: "uint (shiftr w n) = uint w div 2 ^ n" |
|
158 apply (unfold shiftr_def) |
|
159 apply (induct "n") |
|
160 apply simp |
|
161 apply (simp add: shiftr1_div_2 mult_commute |
|
162 zdiv_zmult2_eq [symmetric]) |
|
163 done |
|
164 |
|
165 lemma sshiftr_div_2n: "sint (sshiftr w n) = sint w div 2 ^ n" |
|
166 apply (unfold sshiftr_def) |
|
167 apply (induct "n") |
|
168 apply simp |
|
169 apply (simp add: sshiftr1_div_2 mult_commute |
|
170 zdiv_zmult2_eq [symmetric]) |
|
171 done |
|
172 |
|
173 subsubsection "shift functions in terms of lists of bools" |
|
174 |
|
175 lemmas bshiftr1_no_bin [simp] = |
|
176 bshiftr1_def [where w="number_of w", unfolded to_bl_no_bin, standard] |
|
177 |
|
178 lemma bshiftr1_bl: "to_bl (bshiftr1 b w) = b # butlast (to_bl w)" |
|
179 unfolding bshiftr1_def by (rule word_bl.Abs_inverse) simp |
|
180 |
|
181 lemma shiftl1_of_bl: "shiftl1 (of_bl bl) = of_bl (bl @ [False])" |
|
182 unfolding uint_bl of_bl_no |
|
183 by (simp add: bl_to_bin_aux_append bl_to_bin_def) |
|
184 |
|
185 lemma shiftl1_bl: "shiftl1 (w::'a::len0 word) = of_bl (to_bl w @ [False])" |
|
186 proof - |
|
187 have "shiftl1 w = shiftl1 (of_bl (to_bl w))" by simp |
|
188 also have "\<dots> = of_bl (to_bl w @ [False])" by (rule shiftl1_of_bl) |
|
189 finally show ?thesis . |
|
190 qed |
|
191 |
|
192 lemma bl_shiftl1: |
|
193 "to_bl (shiftl1 (w :: 'a :: len word)) = tl (to_bl w) @ [False]" |
|
194 apply (simp add: shiftl1_bl word_rep_drop drop_Suc drop_Cons') |
|
195 apply (fast intro!: Suc_leI) |
|
196 done |
|
197 |
|
198 lemma shiftr1_bl: "shiftr1 w = of_bl (butlast (to_bl w))" |
|
199 apply (unfold shiftr1_def uint_bl of_bl_def) |
|
200 apply (simp add: butlast_rest_bin word_size) |
|
201 apply (simp add: bin_rest_trunc [symmetric, unfolded One_nat_def]) |
|
202 done |
|
203 |
|
204 lemma bl_shiftr1: |
|
205 "to_bl (shiftr1 (w :: 'a :: len word)) = False # butlast (to_bl w)" |
|
206 unfolding shiftr1_bl |
|
207 by (simp add : word_rep_drop len_gt_0 [THEN Suc_leI]) |
|
208 |
|
209 |
|
210 (* relate the two above : TODO - remove the :: len restriction on |
|
211 this theorem and others depending on it *) |
|
212 lemma shiftl1_rev: |
|
213 "shiftl1 (w :: 'a :: len word) = word_reverse (shiftr1 (word_reverse w))" |
|
214 apply (unfold word_reverse_def) |
|
215 apply (rule word_bl.Rep_inverse' [symmetric]) |
|
216 apply (simp add: bl_shiftl1 bl_shiftr1 word_bl.Abs_inverse) |
|
217 apply (cases "to_bl w") |
|
218 apply auto |
|
219 done |
|
220 |
|
221 lemma shiftl_rev: |
|
222 "shiftl (w :: 'a :: len word) n = word_reverse (shiftr (word_reverse w) n)" |
|
223 apply (unfold shiftl_def shiftr_def) |
|
224 apply (induct "n") |
|
225 apply (auto simp add : shiftl1_rev) |
|
226 done |
|
227 |
|
228 lemmas rev_shiftl = |
|
229 shiftl_rev [where w = "word_reverse w", simplified, standard] |
|
230 |
|
231 lemmas shiftr_rev = rev_shiftl [THEN word_rev_gal', standard] |
|
232 lemmas rev_shiftr = shiftl_rev [THEN word_rev_gal', standard] |
|
233 |
|
234 lemma bl_sshiftr1: |
|
235 "to_bl (sshiftr1 (w :: 'a :: len word)) = hd (to_bl w) # butlast (to_bl w)" |
|
236 apply (unfold sshiftr1_def uint_bl word_size) |
|
237 apply (simp add: butlast_rest_bin word_ubin.eq_norm) |
|
238 apply (simp add: sint_uint) |
|
239 apply (rule nth_equalityI) |
|
240 apply clarsimp |
|
241 apply clarsimp |
|
242 apply (case_tac i) |
|
243 apply (simp_all add: hd_conv_nth length_0_conv [symmetric] |
|
244 nth_bin_to_bl bin_nth.Suc [symmetric] |
|
245 nth_sbintr |
|
246 del: bin_nth.Suc) |
|
247 apply force |
|
248 apply (rule impI) |
|
249 apply (rule_tac f = "bin_nth (uint w)" in arg_cong) |
|
250 apply simp |
|
251 done |
|
252 |
|
253 lemma drop_shiftr: |
|
254 "drop n (to_bl ((w :: 'a :: len word) >> n)) = take (size w - n) (to_bl w)" |
|
255 apply (unfold shiftr_def) |
|
256 apply (induct n) |
|
257 prefer 2 |
|
258 apply (simp add: drop_Suc bl_shiftr1 butlast_drop [symmetric]) |
|
259 apply (rule butlast_take [THEN trans]) |
|
260 apply (auto simp: word_size) |
|
261 done |
|
262 |
|
263 lemma drop_sshiftr: |
|
264 "drop n (to_bl ((w :: 'a :: len word) >>> n)) = take (size w - n) (to_bl w)" |
|
265 apply (unfold sshiftr_def) |
|
266 apply (induct n) |
|
267 prefer 2 |
|
268 apply (simp add: drop_Suc bl_sshiftr1 butlast_drop [symmetric]) |
|
269 apply (rule butlast_take [THEN trans]) |
|
270 apply (auto simp: word_size) |
|
271 done |
|
272 |
|
273 lemma take_shiftr [rule_format] : |
|
274 "n <= size (w :: 'a :: len word) --> take n (to_bl (w >> n)) = |
|
275 replicate n False" |
|
276 apply (unfold shiftr_def) |
|
277 apply (induct n) |
|
278 prefer 2 |
|
279 apply (simp add: bl_shiftr1) |
|
280 apply (rule impI) |
|
281 apply (rule take_butlast [THEN trans]) |
|
282 apply (auto simp: word_size) |
|
283 done |
|
284 |
|
285 lemma take_sshiftr' [rule_format] : |
|
286 "n <= size (w :: 'a :: len word) --> hd (to_bl (w >>> n)) = hd (to_bl w) & |
|
287 take n (to_bl (w >>> n)) = replicate n (hd (to_bl w))" |
|
288 apply (unfold sshiftr_def) |
|
289 apply (induct n) |
|
290 prefer 2 |
|
291 apply (simp add: bl_sshiftr1) |
|
292 apply (rule impI) |
|
293 apply (rule take_butlast [THEN trans]) |
|
294 apply (auto simp: word_size) |
|
295 done |
|
296 |
|
297 lemmas hd_sshiftr = take_sshiftr' [THEN conjunct1, standard] |
|
298 lemmas take_sshiftr = take_sshiftr' [THEN conjunct2, standard] |
|
299 |
|
300 lemma atd_lem: "take n xs = t ==> drop n xs = d ==> xs = t @ d" |
|
301 by (auto intro: append_take_drop_id [symmetric]) |
|
302 |
|
303 lemmas bl_shiftr = atd_lem [OF take_shiftr drop_shiftr] |
|
304 lemmas bl_sshiftr = atd_lem [OF take_sshiftr drop_sshiftr] |
|
305 |
|
306 lemma shiftl_of_bl: "of_bl bl << n = of_bl (bl @ replicate n False)" |
|
307 unfolding shiftl_def |
|
308 by (induct n) (auto simp: shiftl1_of_bl replicate_app_Cons_same) |
|
309 |
|
310 lemma shiftl_bl: |
|
311 "(w::'a::len0 word) << (n::nat) = of_bl (to_bl w @ replicate n False)" |
|
312 proof - |
|
313 have "w << n = of_bl (to_bl w) << n" by simp |
|
314 also have "\<dots> = of_bl (to_bl w @ replicate n False)" by (rule shiftl_of_bl) |
|
315 finally show ?thesis . |
|
316 qed |
|
317 |
|
318 lemmas shiftl_number [simp] = shiftl_def [where w="number_of w", standard] |
|
319 |
|
320 lemma bl_shiftl: |
|
321 "to_bl (w << n) = drop n (to_bl w) @ replicate (min (size w) n) False" |
|
322 by (simp add: shiftl_bl word_rep_drop word_size) |
|
323 |
|
324 lemma shiftl_zero_size: |
|
325 fixes x :: "'a::len0 word" |
|
326 shows "size x <= n ==> x << n = 0" |
|
327 apply (unfold word_size) |
|
328 apply (rule word_eqI) |
|
329 apply (clarsimp simp add: shiftl_bl word_size test_bit_of_bl nth_append) |
|
330 done |
|
331 |
|
332 (* note - the following results use 'a :: len word < number_ring *) |
|
333 |
|
334 lemma shiftl1_2t: "shiftl1 (w :: 'a :: len word) = 2 * w" |
|
335 apply (simp add: shiftl1_def_u) |
|
336 apply (simp only: double_number_of_Bit0 [symmetric]) |
|
337 apply simp |
|
338 done |
|
339 |
|
340 lemma shiftl1_p: "shiftl1 (w :: 'a :: len word) = w + w" |
|
341 apply (simp add: shiftl1_def_u) |
|
342 apply (simp only: double_number_of_Bit0 [symmetric]) |
|
343 apply simp |
|
344 done |
|
345 |
|
346 lemma shiftl_t2n: "shiftl (w :: 'a :: len word) n = 2 ^ n * w" |
|
347 unfolding shiftl_def |
|
348 by (induct n) (auto simp: shiftl1_2t power_Suc) |
|
349 |
|
350 lemma shiftr1_bintr [simp]: |
|
351 "(shiftr1 (number_of w) :: 'a :: len0 word) = |
|
352 number_of (bin_rest (bintrunc (len_of TYPE ('a)) w))" |
|
353 unfolding shiftr1_def word_number_of_def |
|
354 by (simp add : word_ubin.eq_norm) |
|
355 |
|
356 lemma sshiftr1_sbintr [simp] : |
|
357 "(sshiftr1 (number_of w) :: 'a :: len word) = |
|
358 number_of (bin_rest (sbintrunc (len_of TYPE ('a) - 1) w))" |
|
359 unfolding sshiftr1_def word_number_of_def |
|
360 by (simp add : word_sbin.eq_norm) |
|
361 |
|
362 lemma shiftr_no': |
|
363 "w = number_of bin ==> |
|
364 (w::'a::len0 word) >> n = number_of ((bin_rest ^^ n) (bintrunc (size w) bin))" |
|
365 apply clarsimp |
|
366 apply (rule word_eqI) |
|
367 apply (auto simp: nth_shiftr nth_rest_power_bin nth_bintr word_size) |
|
368 done |
|
369 |
|
370 lemma sshiftr_no': |
|
371 "w = number_of bin ==> w >>> n = number_of ((bin_rest ^^ n) |
|
372 (sbintrunc (size w - 1) bin))" |
|
373 apply clarsimp |
|
374 apply (rule word_eqI) |
|
375 apply (auto simp: nth_sshiftr nth_rest_power_bin nth_sbintr word_size) |
|
376 apply (subgoal_tac "na + n = len_of TYPE('a) - Suc 0", simp, simp)+ |
|
377 done |
|
378 |
|
379 lemmas sshiftr_no [simp] = |
|
380 sshiftr_no' [where w = "number_of w", OF refl, unfolded word_size, standard] |
|
381 |
|
382 lemmas shiftr_no [simp] = |
|
383 shiftr_no' [where w = "number_of w", OF refl, unfolded word_size, standard] |
|
384 |
|
385 lemma shiftr1_bl_of': |
|
386 "us = shiftr1 (of_bl bl) ==> length bl <= size us ==> |
|
387 us = of_bl (butlast bl)" |
|
388 by (clarsimp simp: shiftr1_def of_bl_def word_size butlast_rest_bl2bin |
|
389 word_ubin.eq_norm trunc_bl2bin) |
|
390 |
|
391 lemmas shiftr1_bl_of = refl [THEN shiftr1_bl_of', unfolded word_size] |
|
392 |
|
393 lemma shiftr_bl_of' [rule_format]: |
|
394 "us = of_bl bl >> n ==> length bl <= size us --> |
|
395 us = of_bl (take (length bl - n) bl)" |
|
396 apply (unfold shiftr_def) |
|
397 apply hypsubst |
|
398 apply (unfold word_size) |
|
399 apply (induct n) |
|
400 apply clarsimp |
|
401 apply clarsimp |
|
402 apply (subst shiftr1_bl_of) |
|
403 apply simp |
|
404 apply (simp add: butlast_take) |
|
405 done |
|
406 |
|
407 lemmas shiftr_bl_of = refl [THEN shiftr_bl_of', unfolded word_size] |
|
408 |
|
409 lemmas shiftr_bl = word_bl.Rep' [THEN eq_imp_le, THEN shiftr_bl_of, |
|
410 simplified word_size, simplified, THEN eq_reflection, standard] |
|
411 |
|
412 lemma msb_shift': "msb (w::'a::len word) <-> (w >> (size w - 1)) ~= 0" |
|
413 apply (unfold shiftr_bl word_msb_alt) |
|
414 apply (simp add: word_size Suc_le_eq take_Suc) |
|
415 apply (cases "hd (to_bl w)") |
|
416 apply (auto simp: word_1_bl word_0_bl |
|
417 of_bl_rep_False [where n=1 and bs="[]", simplified]) |
|
418 done |
|
419 |
|
420 lemmas msb_shift = msb_shift' [unfolded word_size] |
|
421 |
|
422 lemma align_lem_or [rule_format] : |
|
423 "ALL x m. length x = n + m --> length y = n + m --> |
|
424 drop m x = replicate n False --> take m y = replicate m False --> |
|
425 map2 op | x y = take m x @ drop m y" |
|
426 apply (induct_tac y) |
|
427 apply force |
|
428 apply clarsimp |
|
429 apply (case_tac x, force) |
|
430 apply (case_tac m, auto) |
|
431 apply (drule sym) |
|
432 apply auto |
|
433 apply (induct_tac list, auto) |
|
434 done |
|
435 |
|
436 lemma align_lem_and [rule_format] : |
|
437 "ALL x m. length x = n + m --> length y = n + m --> |
|
438 drop m x = replicate n False --> take m y = replicate m False --> |
|
439 map2 op & x y = replicate (n + m) False" |
|
440 apply (induct_tac y) |
|
441 apply force |
|
442 apply clarsimp |
|
443 apply (case_tac x, force) |
|
444 apply (case_tac m, auto) |
|
445 apply (drule sym) |
|
446 apply auto |
|
447 apply (induct_tac list, auto) |
|
448 done |
|
449 |
|
450 lemma aligned_bl_add_size': |
|
451 "size x - n = m ==> n <= size x ==> drop m (to_bl x) = replicate n False ==> |
|
452 take m (to_bl y) = replicate m False ==> |
|
453 to_bl (x + y) = take m (to_bl x) @ drop m (to_bl y)" |
|
454 apply (subgoal_tac "x AND y = 0") |
|
455 prefer 2 |
|
456 apply (rule word_bl.Rep_eqD) |
|
457 apply (simp add: bl_word_and to_bl_0) |
|
458 apply (rule align_lem_and [THEN trans]) |
|
459 apply (simp_all add: word_size)[5] |
|
460 apply simp |
|
461 apply (subst word_plus_and_or [symmetric]) |
|
462 apply (simp add : bl_word_or) |
|
463 apply (rule align_lem_or) |
|
464 apply (simp_all add: word_size) |
|
465 done |
|
466 |
|
467 lemmas aligned_bl_add_size = refl [THEN aligned_bl_add_size'] |
|
468 |
|
469 subsubsection "Mask" |
|
470 |
|
471 lemma nth_mask': "m = mask n ==> test_bit m i = (i < n & i < size m)" |
|
472 apply (unfold mask_def test_bit_bl) |
|
473 apply (simp only: word_1_bl [symmetric] shiftl_of_bl) |
|
474 apply (clarsimp simp add: word_size) |
|
475 apply (simp only: of_bl_no mask_lem number_of_succ add_diff_cancel2) |
|
476 apply (fold of_bl_no) |
|
477 apply (simp add: word_1_bl) |
|
478 apply (rule test_bit_of_bl [THEN trans, unfolded test_bit_bl word_size]) |
|
479 apply auto |
|
480 done |
|
481 |
|
482 lemmas nth_mask [simp] = refl [THEN nth_mask'] |
|
483 |
|
484 lemma mask_bl: "mask n = of_bl (replicate n True)" |
|
485 by (auto simp add : test_bit_of_bl word_size intro: word_eqI) |
|
486 |
|
487 lemma mask_bin: "mask n = number_of (bintrunc n Int.Min)" |
|
488 by (auto simp add: nth_bintr word_size intro: word_eqI) |
|
489 |
|
490 lemma and_mask_bintr: "w AND mask n = number_of (bintrunc n (uint w))" |
|
491 apply (rule word_eqI) |
|
492 apply (simp add: nth_bintr word_size word_ops_nth_size) |
|
493 apply (auto simp add: test_bit_bin) |
|
494 done |
|
495 |
|
496 lemma and_mask_no: "number_of i AND mask n = number_of (bintrunc n i)" |
|
497 by (auto simp add : nth_bintr word_size word_ops_nth_size intro: word_eqI) |
|
498 |
|
499 lemmas and_mask_wi = and_mask_no [unfolded word_number_of_def] |
|
500 |
|
501 lemma bl_and_mask: |
|
502 "to_bl (w AND mask n :: 'a :: len word) = |
|
503 replicate (len_of TYPE('a) - n) False @ |
|
504 drop (len_of TYPE('a) - n) (to_bl w)" |
|
505 apply (rule nth_equalityI) |
|
506 apply simp |
|
507 apply (clarsimp simp add: to_bl_nth word_size) |
|
508 apply (simp add: word_size word_ops_nth_size) |
|
509 apply (auto simp add: word_size test_bit_bl nth_append nth_rev) |
|
510 done |
|
511 |
|
512 lemmas and_mask_mod_2p = |
|
513 and_mask_bintr [unfolded word_number_of_alt no_bintr_alt] |
|
514 |
|
515 lemma and_mask_lt_2p: "uint (w AND mask n) < 2 ^ n" |
|
516 apply (simp add : and_mask_bintr no_bintr_alt) |
|
517 apply (rule xtr8) |
|
518 prefer 2 |
|
519 apply (rule pos_mod_bound) |
|
520 apply auto |
|
521 done |
|
522 |
|
523 lemmas eq_mod_iff = trans [symmetric, OF int_mod_lem eq_sym_conv] |
|
524 |
|
525 lemma mask_eq_iff: "(w AND mask n) = w <-> uint w < 2 ^ n" |
|
526 apply (simp add: and_mask_bintr word_number_of_def) |
|
527 apply (simp add: word_ubin.inverse_norm) |
|
528 apply (simp add: eq_mod_iff bintrunc_mod2p min_def) |
|
529 apply (fast intro!: lt2p_lem) |
|
530 done |
|
531 |
|
532 lemma and_mask_dvd: "2 ^ n dvd uint w = (w AND mask n = 0)" |
|
533 apply (simp add: dvd_eq_mod_eq_0 and_mask_mod_2p) |
|
534 apply (simp add: word_uint.norm_eq_iff [symmetric] word_of_int_homs) |
|
535 apply (subst word_uint.norm_Rep [symmetric]) |
|
536 apply (simp only: bintrunc_bintrunc_min bintrunc_mod2p [symmetric] min_def) |
|
537 apply auto |
|
538 done |
|
539 |
|
540 lemma and_mask_dvd_nat: "2 ^ n dvd unat w = (w AND mask n = 0)" |
|
541 apply (unfold unat_def) |
|
542 apply (rule trans [OF _ and_mask_dvd]) |
|
543 apply (unfold dvd_def) |
|
544 apply auto |
|
545 apply (drule uint_ge_0 [THEN nat_int.Abs_inverse' [simplified], symmetric]) |
|
546 apply (simp add : int_mult int_power) |
|
547 apply (simp add : nat_mult_distrib nat_power_eq) |
|
548 done |
|
549 |
|
550 lemma word_2p_lem: |
|
551 "n < size w ==> w < 2 ^ n = (uint (w :: 'a :: len word) < 2 ^ n)" |
|
552 apply (unfold word_size word_less_alt word_number_of_alt) |
|
553 apply (clarsimp simp add: word_of_int_power_hom word_uint.eq_norm |
|
554 int_mod_eq' |
|
555 simp del: word_of_int_bin) |
|
556 done |
|
557 |
|
558 lemma less_mask_eq: "x < 2 ^ n ==> x AND mask n = (x :: 'a :: len word)" |
|
559 apply (unfold word_less_alt word_number_of_alt) |
|
560 apply (clarsimp simp add: and_mask_mod_2p word_of_int_power_hom |
|
561 word_uint.eq_norm |
|
562 simp del: word_of_int_bin) |
|
563 apply (drule xtr8 [rotated]) |
|
564 apply (rule int_mod_le) |
|
565 apply (auto simp add : mod_pos_pos_trivial) |
|
566 done |
|
567 |
|
568 lemmas mask_eq_iff_w2p = |
|
569 trans [OF mask_eq_iff word_2p_lem [symmetric], standard] |
|
570 |
|
571 lemmas and_mask_less' = |
|
572 iffD2 [OF word_2p_lem and_mask_lt_2p, simplified word_size, standard] |
|
573 |
|
574 lemma and_mask_less_size: "n < size x ==> x AND mask n < 2^n" |
|
575 unfolding word_size by (erule and_mask_less') |
|
576 |
|
577 lemma word_mod_2p_is_mask': |
|
578 "c = 2 ^ n ==> c > 0 ==> x mod c = (x :: 'a :: len word) AND mask n" |
|
579 by (clarsimp simp add: word_mod_def uint_2p and_mask_mod_2p) |
|
580 |
|
581 lemmas word_mod_2p_is_mask = refl [THEN word_mod_2p_is_mask'] |
|
582 |
|
583 lemma mask_eqs: |
|
584 "(a AND mask n) + b AND mask n = a + b AND mask n" |
|
585 "a + (b AND mask n) AND mask n = a + b AND mask n" |
|
586 "(a AND mask n) - b AND mask n = a - b AND mask n" |
|
587 "a - (b AND mask n) AND mask n = a - b AND mask n" |
|
588 "a * (b AND mask n) AND mask n = a * b AND mask n" |
|
589 "(b AND mask n) * a AND mask n = b * a AND mask n" |
|
590 "(a AND mask n) + (b AND mask n) AND mask n = a + b AND mask n" |
|
591 "(a AND mask n) - (b AND mask n) AND mask n = a - b AND mask n" |
|
592 "(a AND mask n) * (b AND mask n) AND mask n = a * b AND mask n" |
|
593 "- (a AND mask n) AND mask n = - a AND mask n" |
|
594 "word_succ (a AND mask n) AND mask n = word_succ a AND mask n" |
|
595 "word_pred (a AND mask n) AND mask n = word_pred a AND mask n" |
|
596 using word_of_int_Ex [where x=a] word_of_int_Ex [where x=b] |
|
597 by (auto simp: and_mask_wi bintr_ariths bintr_arith1s new_word_of_int_homs) |
|
598 |
|
599 lemma mask_power_eq: |
|
600 "(x AND mask n) ^ k AND mask n = x ^ k AND mask n" |
|
601 using word_of_int_Ex [where x=x] |
|
602 by (clarsimp simp: and_mask_wi word_of_int_power_hom bintr_ariths) |
|
603 |
|
604 |
|
605 subsubsection "Revcast" |
|
606 |
|
607 lemmas revcast_def' = revcast_def [simplified] |
|
608 lemmas revcast_def'' = revcast_def' [simplified word_size] |
|
609 lemmas revcast_no_def [simp] = |
|
610 revcast_def' [where w="number_of w", unfolded word_size, standard] |
|
611 |
|
612 lemma to_bl_revcast: |
|
613 "to_bl (revcast w :: 'a :: len0 word) = |
|
614 takefill False (len_of TYPE ('a)) (to_bl w)" |
|
615 apply (unfold revcast_def' word_size) |
|
616 apply (rule word_bl.Abs_inverse) |
|
617 apply simp |
|
618 done |
|
619 |
|
620 lemma revcast_rev_ucast': |
|
621 "cs = [rc, uc] ==> rc = revcast (word_reverse w) ==> uc = ucast w ==> |
|
622 rc = word_reverse uc" |
|
623 apply (unfold ucast_def revcast_def' Let_def word_reverse_def) |
|
624 apply (clarsimp simp add : to_bl_of_bin takefill_bintrunc) |
|
625 apply (simp add : word_bl.Abs_inverse word_size) |
|
626 done |
|
627 |
|
628 lemmas revcast_rev_ucast = revcast_rev_ucast' [OF refl refl refl] |
|
629 |
|
630 lemmas revcast_ucast = revcast_rev_ucast |
|
631 [where w = "word_reverse w", simplified word_rev_rev, standard] |
|
632 |
|
633 lemmas ucast_revcast = revcast_rev_ucast [THEN word_rev_gal', standard] |
|
634 lemmas ucast_rev_revcast = revcast_ucast [THEN word_rev_gal', standard] |
|
635 |
|
636 |
|
637 -- "linking revcast and cast via shift" |
|
638 |
|
639 lemmas wsst_TYs = source_size target_size word_size |
|
640 |
|
641 lemma revcast_down_uu': |
|
642 "rc = revcast ==> source_size rc = target_size rc + n ==> |
|
643 rc (w :: 'a :: len word) = ucast (w >> n)" |
|
644 apply (simp add: revcast_def') |
|
645 apply (rule word_bl.Rep_inverse') |
|
646 apply (rule trans, rule ucast_down_drop) |
|
647 prefer 2 |
|
648 apply (rule trans, rule drop_shiftr) |
|
649 apply (auto simp: takefill_alt wsst_TYs) |
|
650 done |
|
651 |
|
652 lemma revcast_down_us': |
|
653 "rc = revcast ==> source_size rc = target_size rc + n ==> |
|
654 rc (w :: 'a :: len word) = ucast (w >>> n)" |
|
655 apply (simp add: revcast_def') |
|
656 apply (rule word_bl.Rep_inverse') |
|
657 apply (rule trans, rule ucast_down_drop) |
|
658 prefer 2 |
|
659 apply (rule trans, rule drop_sshiftr) |
|
660 apply (auto simp: takefill_alt wsst_TYs) |
|
661 done |
|
662 |
|
663 lemma revcast_down_su': |
|
664 "rc = revcast ==> source_size rc = target_size rc + n ==> |
|
665 rc (w :: 'a :: len word) = scast (w >> n)" |
|
666 apply (simp add: revcast_def') |
|
667 apply (rule word_bl.Rep_inverse') |
|
668 apply (rule trans, rule scast_down_drop) |
|
669 prefer 2 |
|
670 apply (rule trans, rule drop_shiftr) |
|
671 apply (auto simp: takefill_alt wsst_TYs) |
|
672 done |
|
673 |
|
674 lemma revcast_down_ss': |
|
675 "rc = revcast ==> source_size rc = target_size rc + n ==> |
|
676 rc (w :: 'a :: len word) = scast (w >>> n)" |
|
677 apply (simp add: revcast_def') |
|
678 apply (rule word_bl.Rep_inverse') |
|
679 apply (rule trans, rule scast_down_drop) |
|
680 prefer 2 |
|
681 apply (rule trans, rule drop_sshiftr) |
|
682 apply (auto simp: takefill_alt wsst_TYs) |
|
683 done |
|
684 |
|
685 lemmas revcast_down_uu = refl [THEN revcast_down_uu'] |
|
686 lemmas revcast_down_us = refl [THEN revcast_down_us'] |
|
687 lemmas revcast_down_su = refl [THEN revcast_down_su'] |
|
688 lemmas revcast_down_ss = refl [THEN revcast_down_ss'] |
|
689 |
|
690 lemma cast_down_rev: |
|
691 "uc = ucast ==> source_size uc = target_size uc + n ==> |
|
692 uc w = revcast ((w :: 'a :: len word) << n)" |
|
693 apply (unfold shiftl_rev) |
|
694 apply clarify |
|
695 apply (simp add: revcast_rev_ucast) |
|
696 apply (rule word_rev_gal') |
|
697 apply (rule trans [OF _ revcast_rev_ucast]) |
|
698 apply (rule revcast_down_uu [symmetric]) |
|
699 apply (auto simp add: wsst_TYs) |
|
700 done |
|
701 |
|
702 lemma revcast_up': |
|
703 "rc = revcast ==> source_size rc + n = target_size rc ==> |
|
704 rc w = (ucast w :: 'a :: len word) << n" |
|
705 apply (simp add: revcast_def') |
|
706 apply (rule word_bl.Rep_inverse') |
|
707 apply (simp add: takefill_alt) |
|
708 apply (rule bl_shiftl [THEN trans]) |
|
709 apply (subst ucast_up_app) |
|
710 apply (auto simp add: wsst_TYs) |
|
711 done |
|
712 |
|
713 lemmas revcast_up = refl [THEN revcast_up'] |
|
714 |
|
715 lemmas rc1 = revcast_up [THEN |
|
716 revcast_rev_ucast [symmetric, THEN trans, THEN word_rev_gal, symmetric]] |
|
717 lemmas rc2 = revcast_down_uu [THEN |
|
718 revcast_rev_ucast [symmetric, THEN trans, THEN word_rev_gal, symmetric]] |
|
719 |
|
720 lemmas ucast_up = |
|
721 rc1 [simplified rev_shiftr [symmetric] revcast_ucast [symmetric]] |
|
722 lemmas ucast_down = |
|
723 rc2 [simplified rev_shiftr revcast_ucast [symmetric]] |
|
724 |
|
725 |
|
726 subsubsection "Slices" |
|
727 |
|
728 lemmas slice1_no_bin [simp] = |
|
729 slice1_def [where w="number_of w", unfolded to_bl_no_bin, standard] |
|
730 |
|
731 lemmas slice_no_bin [simp] = |
|
732 trans [OF slice_def [THEN meta_eq_to_obj_eq] |
|
733 slice1_no_bin [THEN meta_eq_to_obj_eq], |
|
734 unfolded word_size, standard] |
|
735 |
|
736 lemma slice1_0 [simp] : "slice1 n 0 = 0" |
|
737 unfolding slice1_def by (simp add : to_bl_0) |
|
738 |
|
739 lemma slice_0 [simp] : "slice n 0 = 0" |
|
740 unfolding slice_def by auto |
|
741 |
|
742 lemma slice_take': "slice n w = of_bl (take (size w - n) (to_bl w))" |
|
743 unfolding slice_def' slice1_def |
|
744 by (simp add : takefill_alt word_size) |
|
745 |
|
746 lemmas slice_take = slice_take' [unfolded word_size] |
|
747 |
|
748 -- "shiftr to a word of the same size is just slice, |
|
749 slice is just shiftr then ucast" |
|
750 lemmas shiftr_slice = trans |
|
751 [OF shiftr_bl [THEN meta_eq_to_obj_eq] slice_take [symmetric], standard] |
|
752 |
|
753 lemma slice_shiftr: "slice n w = ucast (w >> n)" |
|
754 apply (unfold slice_take shiftr_bl) |
|
755 apply (rule ucast_of_bl_up [symmetric]) |
|
756 apply (simp add: word_size) |
|
757 done |
|
758 |
|
759 lemma nth_slice: |
|
760 "(slice n w :: 'a :: len0 word) !! m = |
|
761 (w !! (m + n) & m < len_of TYPE ('a))" |
|
762 unfolding slice_shiftr |
|
763 by (simp add : nth_ucast nth_shiftr) |
|
764 |
|
765 lemma slice1_down_alt': |
|
766 "sl = slice1 n w ==> fs = size sl ==> fs + k = n ==> |
|
767 to_bl sl = takefill False fs (drop k (to_bl w))" |
|
768 unfolding slice1_def word_size of_bl_def uint_bl |
|
769 by (clarsimp simp: word_ubin.eq_norm bl_bin_bl_rep_drop drop_takefill) |
|
770 |
|
771 lemma slice1_up_alt': |
|
772 "sl = slice1 n w ==> fs = size sl ==> fs = n + k ==> |
|
773 to_bl sl = takefill False fs (replicate k False @ (to_bl w))" |
|
774 apply (unfold slice1_def word_size of_bl_def uint_bl) |
|
775 apply (clarsimp simp: word_ubin.eq_norm bl_bin_bl_rep_drop |
|
776 takefill_append [symmetric]) |
|
777 apply (rule_tac f = "%k. takefill False (len_of TYPE('a)) |
|
778 (replicate k False @ bin_to_bl (len_of TYPE('b)) (uint w))" in arg_cong) |
|
779 apply arith |
|
780 done |
|
781 |
|
782 lemmas sd1 = slice1_down_alt' [OF refl refl, unfolded word_size] |
|
783 lemmas su1 = slice1_up_alt' [OF refl refl, unfolded word_size] |
|
784 lemmas slice1_down_alt = le_add_diff_inverse [THEN sd1] |
|
785 lemmas slice1_up_alts = |
|
786 le_add_diff_inverse [symmetric, THEN su1] |
|
787 le_add_diff_inverse2 [symmetric, THEN su1] |
|
788 |
|
789 lemma ucast_slice1: "ucast w = slice1 (size w) w" |
|
790 unfolding slice1_def ucast_bl |
|
791 by (simp add : takefill_same' word_size) |
|
792 |
|
793 lemma ucast_slice: "ucast w = slice 0 w" |
|
794 unfolding slice_def by (simp add : ucast_slice1) |
|
795 |
|
796 lemmas slice_id = trans [OF ucast_slice [symmetric] ucast_id] |
|
797 |
|
798 lemma revcast_slice1': |
|
799 "rc = revcast w ==> slice1 (size rc) w = rc" |
|
800 unfolding slice1_def revcast_def' by (simp add : word_size) |
|
801 |
|
802 lemmas revcast_slice1 = refl [THEN revcast_slice1'] |
|
803 |
|
804 lemma slice1_tf_tf': |
|
805 "to_bl (slice1 n w :: 'a :: len0 word) = |
|
806 rev (takefill False (len_of TYPE('a)) (rev (takefill False n (to_bl w))))" |
|
807 unfolding slice1_def by (rule word_rev_tf) |
|
808 |
|
809 lemmas slice1_tf_tf = slice1_tf_tf' |
|
810 [THEN word_bl.Rep_inverse', symmetric, standard] |
|
811 |
|
812 lemma rev_slice1: |
|
813 "n + k = len_of TYPE('a) + len_of TYPE('b) \<Longrightarrow> |
|
814 slice1 n (word_reverse w :: 'b :: len0 word) = |
|
815 word_reverse (slice1 k w :: 'a :: len0 word)" |
|
816 apply (unfold word_reverse_def slice1_tf_tf) |
|
817 apply (rule word_bl.Rep_inverse') |
|
818 apply (rule rev_swap [THEN iffD1]) |
|
819 apply (rule trans [symmetric]) |
|
820 apply (rule tf_rev) |
|
821 apply (simp add: word_bl.Abs_inverse) |
|
822 apply (simp add: word_bl.Abs_inverse) |
|
823 done |
|
824 |
|
825 lemma rev_slice': |
|
826 "res = slice n (word_reverse w) ==> n + k + size res = size w ==> |
|
827 res = word_reverse (slice k w)" |
|
828 apply (unfold slice_def word_size) |
|
829 apply clarify |
|
830 apply (rule rev_slice1) |
|
831 apply arith |
|
832 done |
|
833 |
|
834 lemmas rev_slice = refl [THEN rev_slice', unfolded word_size] |
|
835 |
|
836 lemmas sym_notr = |
|
837 not_iff [THEN iffD2, THEN not_sym, THEN not_iff [THEN iffD1]] |
|
838 |
|
839 -- {* problem posed by TPHOLs referee: |
|
840 criterion for overflow of addition of signed integers *} |
|
841 |
|
842 lemma sofl_test: |
|
843 "(sint (x :: 'a :: len word) + sint y = sint (x + y)) = |
|
844 ((((x+y) XOR x) AND ((x+y) XOR y)) >> (size x - 1) = 0)" |
|
845 apply (unfold word_size) |
|
846 apply (cases "len_of TYPE('a)", simp) |
|
847 apply (subst msb_shift [THEN sym_notr]) |
|
848 apply (simp add: word_ops_msb) |
|
849 apply (simp add: word_msb_sint) |
|
850 apply safe |
|
851 apply simp_all |
|
852 apply (unfold sint_word_ariths) |
|
853 apply (unfold word_sbin.set_iff_norm [symmetric] sints_num) |
|
854 apply safe |
|
855 apply (insert sint_range' [where x=x]) |
|
856 apply (insert sint_range' [where x=y]) |
|
857 defer |
|
858 apply (simp (no_asm), arith) |
|
859 apply (simp (no_asm), arith) |
|
860 defer |
|
861 defer |
|
862 apply (simp (no_asm), arith) |
|
863 apply (simp (no_asm), arith) |
|
864 apply (rule notI [THEN notnotD], |
|
865 drule leI not_leE, |
|
866 drule sbintrunc_inc sbintrunc_dec, |
|
867 simp)+ |
|
868 done |
|
869 |
|
870 |
|
871 subsection "Split and cat" |
|
872 |
|
873 lemmas word_split_bin' = word_split_def [THEN meta_eq_to_obj_eq, standard] |
|
874 lemmas word_cat_bin' = word_cat_def [THEN meta_eq_to_obj_eq, standard] |
|
875 |
|
876 lemma word_rsplit_no: |
|
877 "(word_rsplit (number_of bin :: 'b :: len0 word) :: 'a word list) = |
|
878 map number_of (bin_rsplit (len_of TYPE('a :: len)) |
|
879 (len_of TYPE('b), bintrunc (len_of TYPE('b)) bin))" |
|
880 apply (unfold word_rsplit_def word_no_wi) |
|
881 apply (simp add: word_ubin.eq_norm) |
|
882 done |
|
883 |
|
884 lemmas word_rsplit_no_cl [simp] = word_rsplit_no |
|
885 [unfolded bin_rsplitl_def bin_rsplit_l [symmetric]] |
|
886 |
|
887 lemma test_bit_cat: |
|
888 "wc = word_cat a b ==> wc !! n = (n < size wc & |
|
889 (if n < size b then b !! n else a !! (n - size b)))" |
|
890 apply (unfold word_cat_bin' test_bit_bin) |
|
891 apply (auto simp add : word_ubin.eq_norm nth_bintr bin_nth_cat word_size) |
|
892 apply (erule bin_nth_uint_imp) |
|
893 done |
|
894 |
|
895 lemma word_cat_bl: "word_cat a b = of_bl (to_bl a @ to_bl b)" |
|
896 apply (unfold of_bl_def to_bl_def word_cat_bin') |
|
897 apply (simp add: bl_to_bin_app_cat) |
|
898 done |
|
899 |
|
900 lemma of_bl_append: |
|
901 "(of_bl (xs @ ys) :: 'a :: len word) = of_bl xs * 2^(length ys) + of_bl ys" |
|
902 apply (unfold of_bl_def) |
|
903 apply (simp add: bl_to_bin_app_cat bin_cat_num) |
|
904 apply (simp add: word_of_int_power_hom [symmetric] new_word_of_int_hom_syms) |
|
905 done |
|
906 |
|
907 lemma of_bl_False [simp]: |
|
908 "of_bl (False#xs) = of_bl xs" |
|
909 by (rule word_eqI) |
|
910 (auto simp add: test_bit_of_bl nth_append) |
|
911 |
|
912 lemma of_bl_True: |
|
913 "(of_bl (True#xs)::'a::len word) = 2^length xs + of_bl xs" |
|
914 by (subst of_bl_append [where xs="[True]", simplified]) |
|
915 (simp add: word_1_bl) |
|
916 |
|
917 lemma of_bl_Cons: |
|
918 "of_bl (x#xs) = of_bool x * 2^length xs + of_bl xs" |
|
919 by (cases x) (simp_all add: of_bl_True) |
|
920 |
|
921 lemma split_uint_lem: "bin_split n (uint (w :: 'a :: len0 word)) = (a, b) ==> |
|
922 a = bintrunc (len_of TYPE('a) - n) a & b = bintrunc (len_of TYPE('a)) b" |
|
923 apply (frule word_ubin.norm_Rep [THEN ssubst]) |
|
924 apply (drule bin_split_trunc1) |
|
925 apply (drule sym [THEN trans]) |
|
926 apply assumption |
|
927 apply safe |
|
928 done |
|
929 |
|
930 lemma word_split_bl': |
|
931 "std = size c - size b ==> (word_split c = (a, b)) ==> |
|
932 (a = of_bl (take std (to_bl c)) & b = of_bl (drop std (to_bl c)))" |
|
933 apply (unfold word_split_bin') |
|
934 apply safe |
|
935 defer |
|
936 apply (clarsimp split: prod.splits) |
|
937 apply (drule word_ubin.norm_Rep [THEN ssubst]) |
|
938 apply (drule split_bintrunc) |
|
939 apply (simp add : of_bl_def bl2bin_drop word_size |
|
940 word_ubin.norm_eq_iff [symmetric] min_def del : word_ubin.norm_Rep) |
|
941 apply (clarsimp split: prod.splits) |
|
942 apply (frule split_uint_lem [THEN conjunct1]) |
|
943 apply (unfold word_size) |
|
944 apply (cases "len_of TYPE('a) >= len_of TYPE('b)") |
|
945 defer |
|
946 apply (simp add: word_0_bl word_0_wi_Pls) |
|
947 apply (simp add : of_bl_def to_bl_def) |
|
948 apply (subst bin_split_take1 [symmetric]) |
|
949 prefer 2 |
|
950 apply assumption |
|
951 apply simp |
|
952 apply (erule thin_rl) |
|
953 apply (erule arg_cong [THEN trans]) |
|
954 apply (simp add : word_ubin.norm_eq_iff [symmetric]) |
|
955 done |
|
956 |
|
957 lemma word_split_bl: "std = size c - size b ==> |
|
958 (a = of_bl (take std (to_bl c)) & b = of_bl (drop std (to_bl c))) <-> |
|
959 word_split c = (a, b)" |
|
960 apply (rule iffI) |
|
961 defer |
|
962 apply (erule (1) word_split_bl') |
|
963 apply (case_tac "word_split c") |
|
964 apply (auto simp add : word_size) |
|
965 apply (frule word_split_bl' [rotated]) |
|
966 apply (auto simp add : word_size) |
|
967 done |
|
968 |
|
969 lemma word_split_bl_eq: |
|
970 "(word_split (c::'a::len word) :: ('c :: len0 word * 'd :: len0 word)) = |
|
971 (of_bl (take (len_of TYPE('a::len) - len_of TYPE('d::len0)) (to_bl c)), |
|
972 of_bl (drop (len_of TYPE('a) - len_of TYPE('d)) (to_bl c)))" |
|
973 apply (rule word_split_bl [THEN iffD1]) |
|
974 apply (unfold word_size) |
|
975 apply (rule refl conjI)+ |
|
976 done |
|
977 |
|
978 -- "keep quantifiers for use in simplification" |
|
979 lemma test_bit_split': |
|
980 "word_split c = (a, b) --> (ALL n m. b !! n = (n < size b & c !! n) & |
|
981 a !! m = (m < size a & c !! (m + size b)))" |
|
982 apply (unfold word_split_bin' test_bit_bin) |
|
983 apply (clarify) |
|
984 apply (clarsimp simp: word_ubin.eq_norm nth_bintr word_size split: prod.splits) |
|
985 apply (drule bin_nth_split) |
|
986 apply safe |
|
987 apply (simp_all add: add_commute) |
|
988 apply (erule bin_nth_uint_imp)+ |
|
989 done |
|
990 |
|
991 lemma test_bit_split: |
|
992 "word_split c = (a, b) \<Longrightarrow> |
|
993 (\<forall>n\<Colon>nat. b !! n \<longleftrightarrow> n < size b \<and> c !! n) \<and> (\<forall>m\<Colon>nat. a !! m \<longleftrightarrow> m < size a \<and> c !! (m + size b))" |
|
994 by (simp add: test_bit_split') |
|
995 |
|
996 lemma test_bit_split_eq: "word_split c = (a, b) <-> |
|
997 ((ALL n::nat. b !! n = (n < size b & c !! n)) & |
|
998 (ALL m::nat. a !! m = (m < size a & c !! (m + size b))))" |
|
999 apply (rule_tac iffI) |
|
1000 apply (rule_tac conjI) |
|
1001 apply (erule test_bit_split [THEN conjunct1]) |
|
1002 apply (erule test_bit_split [THEN conjunct2]) |
|
1003 apply (case_tac "word_split c") |
|
1004 apply (frule test_bit_split) |
|
1005 apply (erule trans) |
|
1006 apply (fastsimp intro ! : word_eqI simp add : word_size) |
|
1007 done |
|
1008 |
|
1009 -- {* this odd result is analogous to @{text "ucast_id"}, |
|
1010 result to the length given by the result type *} |
|
1011 |
|
1012 lemma word_cat_id: "word_cat a b = b" |
|
1013 unfolding word_cat_bin' by (simp add: word_ubin.inverse_norm) |
|
1014 |
|
1015 -- "limited hom result" |
|
1016 lemma word_cat_hom: |
|
1017 "len_of TYPE('a::len0) <= len_of TYPE('b::len0) + len_of TYPE ('c::len0) |
|
1018 ==> |
|
1019 (word_cat (word_of_int w :: 'b word) (b :: 'c word) :: 'a word) = |
|
1020 word_of_int (bin_cat w (size b) (uint b))" |
|
1021 apply (unfold word_cat_def word_size) |
|
1022 apply (clarsimp simp add: word_ubin.norm_eq_iff [symmetric] |
|
1023 word_ubin.eq_norm bintr_cat min_max.inf_absorb1) |
|
1024 done |
|
1025 |
|
1026 lemma word_cat_split_alt: |
|
1027 "size w <= size u + size v ==> word_split w = (u, v) ==> word_cat u v = w" |
|
1028 apply (rule word_eqI) |
|
1029 apply (drule test_bit_split) |
|
1030 apply (clarsimp simp add : test_bit_cat word_size) |
|
1031 apply safe |
|
1032 apply arith |
|
1033 done |
|
1034 |
|
1035 lemmas word_cat_split_size = |
|
1036 sym [THEN [2] word_cat_split_alt [symmetric], standard] |
|
1037 |
|
1038 |
|
1039 subsubsection "Split and slice" |
|
1040 |
|
1041 lemma split_slices: |
|
1042 "word_split w = (u, v) ==> u = slice (size v) w & v = slice 0 w" |
|
1043 apply (drule test_bit_split) |
|
1044 apply (rule conjI) |
|
1045 apply (rule word_eqI, clarsimp simp: nth_slice word_size)+ |
|
1046 done |
|
1047 |
|
1048 lemma slice_cat1': |
|
1049 "wc = word_cat a b ==> size wc >= size a + size b ==> slice (size b) wc = a" |
|
1050 apply safe |
|
1051 apply (rule word_eqI) |
|
1052 apply (simp add: nth_slice test_bit_cat word_size) |
|
1053 done |
|
1054 |
|
1055 lemmas slice_cat1 = refl [THEN slice_cat1'] |
|
1056 lemmas slice_cat2 = trans [OF slice_id word_cat_id] |
|
1057 |
|
1058 lemma cat_slices: |
|
1059 "a = slice n c ==> b = slice 0 c ==> n = size b ==> |
|
1060 size a + size b >= size c ==> word_cat a b = c" |
|
1061 apply safe |
|
1062 apply (rule word_eqI) |
|
1063 apply (simp add: nth_slice test_bit_cat word_size) |
|
1064 apply safe |
|
1065 apply arith |
|
1066 done |
|
1067 |
|
1068 lemma word_split_cat_alt: |
|
1069 "w = word_cat u v ==> size u + size v <= size w ==> word_split w = (u, v)" |
|
1070 apply (case_tac "word_split ?w") |
|
1071 apply (rule trans, assumption) |
|
1072 apply (drule test_bit_split) |
|
1073 apply safe |
|
1074 apply (rule word_eqI, clarsimp simp: test_bit_cat word_size)+ |
|
1075 done |
|
1076 |
|
1077 lemmas word_cat_bl_no_bin [simp] = |
|
1078 word_cat_bl [where a="number_of a" |
|
1079 and b="number_of b", |
|
1080 unfolded to_bl_no_bin, standard] |
|
1081 |
|
1082 lemmas word_split_bl_no_bin [simp] = |
|
1083 word_split_bl_eq [where c="number_of c", unfolded to_bl_no_bin, standard] |
|
1084 |
|
1085 -- {* this odd result arises from the fact that the statement of the |
|
1086 result implies that the decoded words are of the same type, |
|
1087 and therefore of the same length, as the original word *} |
|
1088 |
|
1089 lemma word_rsplit_same: "word_rsplit w = [w]" |
|
1090 unfolding word_rsplit_def by (simp add : bin_rsplit_all) |
|
1091 |
|
1092 lemma word_rsplit_empty_iff_size: |
|
1093 "(word_rsplit w = []) = (size w = 0)" |
|
1094 unfolding word_rsplit_def bin_rsplit_def word_size |
|
1095 by (simp add: bin_rsplit_aux_simp_alt Let_def split: Product_Type.split_split) |
|
1096 |
|
1097 lemma test_bit_rsplit: |
|
1098 "sw = word_rsplit w ==> m < size (hd sw :: 'a :: len word) ==> |
|
1099 k < length sw ==> (rev sw ! k) !! m = (w !! (k * size (hd sw) + m))" |
|
1100 apply (unfold word_rsplit_def word_test_bit_def) |
|
1101 apply (rule trans) |
|
1102 apply (rule_tac f = "%x. bin_nth x m" in arg_cong) |
|
1103 apply (rule nth_map [symmetric]) |
|
1104 apply simp |
|
1105 apply (rule bin_nth_rsplit) |
|
1106 apply simp_all |
|
1107 apply (simp add : word_size rev_map) |
|
1108 apply (rule trans) |
|
1109 defer |
|
1110 apply (rule map_ident [THEN fun_cong]) |
|
1111 apply (rule refl [THEN map_cong]) |
|
1112 apply (simp add : word_ubin.eq_norm) |
|
1113 apply (erule bin_rsplit_size_sign [OF len_gt_0 refl]) |
|
1114 done |
|
1115 |
|
1116 lemma word_rcat_bl: "word_rcat wl == of_bl (concat (map to_bl wl))" |
|
1117 unfolding word_rcat_def to_bl_def' of_bl_def |
|
1118 by (clarsimp simp add : bin_rcat_bl) |
|
1119 |
|
1120 lemma size_rcat_lem': |
|
1121 "size (concat (map to_bl wl)) = length wl * size (hd wl)" |
|
1122 unfolding word_size by (induct wl) auto |
|
1123 |
|
1124 lemmas size_rcat_lem = size_rcat_lem' [unfolded word_size] |
|
1125 |
|
1126 lemmas td_gal_lt_len = len_gt_0 [THEN td_gal_lt, standard] |
|
1127 |
|
1128 lemma nth_rcat_lem' [rule_format] : |
|
1129 "sw = size (hd wl :: 'a :: len word) ==> (ALL n. n < size wl * sw --> |
|
1130 rev (concat (map to_bl wl)) ! n = |
|
1131 rev (to_bl (rev wl ! (n div sw))) ! (n mod sw))" |
|
1132 apply (unfold word_size) |
|
1133 apply (induct "wl") |
|
1134 apply clarsimp |
|
1135 apply (clarsimp simp add : nth_append size_rcat_lem) |
|
1136 apply (simp (no_asm_use) only: mult_Suc [symmetric] |
|
1137 td_gal_lt_len less_Suc_eq_le mod_div_equality') |
|
1138 apply clarsimp |
|
1139 done |
|
1140 |
|
1141 lemmas nth_rcat_lem = refl [THEN nth_rcat_lem', unfolded word_size] |
|
1142 |
|
1143 lemma test_bit_rcat: |
|
1144 "sw = size (hd wl :: 'a :: len word) ==> rc = word_rcat wl ==> rc !! n = |
|
1145 (n < size rc & n div sw < size wl & (rev wl) ! (n div sw) !! (n mod sw))" |
|
1146 apply (unfold word_rcat_bl word_size) |
|
1147 apply (clarsimp simp add : |
|
1148 test_bit_of_bl size_rcat_lem word_size td_gal_lt_len) |
|
1149 apply safe |
|
1150 apply (auto simp add : |
|
1151 test_bit_bl word_size td_gal_lt_len [THEN iffD2, THEN nth_rcat_lem]) |
|
1152 done |
|
1153 |
|
1154 lemma foldl_eq_foldr [rule_format] : |
|
1155 "ALL x. foldl op + x xs = foldr op + (x # xs) (0 :: 'a :: comm_monoid_add)" |
|
1156 by (induct xs) (auto simp add : add_assoc) |
|
1157 |
|
1158 lemmas test_bit_cong = arg_cong [where f = "test_bit", THEN fun_cong] |
|
1159 |
|
1160 lemmas test_bit_rsplit_alt = |
|
1161 trans [OF nth_rev_alt [THEN test_bit_cong] |
|
1162 test_bit_rsplit [OF refl asm_rl diff_Suc_less]] |
|
1163 |
|
1164 -- "lazy way of expressing that u and v, and su and sv, have same types" |
|
1165 lemma word_rsplit_len_indep': |
|
1166 "[u,v] = p ==> [su,sv] = q ==> word_rsplit u = su ==> |
|
1167 word_rsplit v = sv ==> length su = length sv" |
|
1168 apply (unfold word_rsplit_def) |
|
1169 apply (auto simp add : bin_rsplit_len_indep) |
|
1170 done |
|
1171 |
|
1172 lemmas word_rsplit_len_indep = word_rsplit_len_indep' [OF refl refl refl refl] |
|
1173 |
|
1174 lemma length_word_rsplit_size: |
|
1175 "n = len_of TYPE ('a :: len) ==> |
|
1176 (length (word_rsplit w :: 'a word list) <= m) = (size w <= m * n)" |
|
1177 apply (unfold word_rsplit_def word_size) |
|
1178 apply (clarsimp simp add : bin_rsplit_len_le) |
|
1179 done |
|
1180 |
|
1181 lemmas length_word_rsplit_lt_size = |
|
1182 length_word_rsplit_size [unfolded Not_eq_iff linorder_not_less [symmetric]] |
|
1183 |
|
1184 lemma length_word_rsplit_exp_size: |
|
1185 "n = len_of TYPE ('a :: len) ==> |
|
1186 length (word_rsplit w :: 'a word list) = (size w + n - 1) div n" |
|
1187 unfolding word_rsplit_def by (clarsimp simp add : word_size bin_rsplit_len) |
|
1188 |
|
1189 lemma length_word_rsplit_even_size: |
|
1190 "n = len_of TYPE ('a :: len) ==> size w = m * n ==> |
|
1191 length (word_rsplit w :: 'a word list) = m" |
|
1192 by (clarsimp simp add : length_word_rsplit_exp_size given_quot_alt) |
|
1193 |
|
1194 lemmas length_word_rsplit_exp_size' = refl [THEN length_word_rsplit_exp_size] |
|
1195 |
|
1196 (* alternative proof of word_rcat_rsplit *) |
|
1197 lemmas tdle = iffD2 [OF split_div_lemma refl, THEN conjunct1] |
|
1198 lemmas dtle = xtr4 [OF tdle mult_commute] |
|
1199 |
|
1200 lemma word_rcat_rsplit: "word_rcat (word_rsplit w) = w" |
|
1201 apply (rule word_eqI) |
|
1202 apply (clarsimp simp add : test_bit_rcat word_size) |
|
1203 apply (subst refl [THEN test_bit_rsplit]) |
|
1204 apply (simp_all add: word_size |
|
1205 refl [THEN length_word_rsplit_size [simplified not_less [symmetric], simplified]]) |
|
1206 apply safe |
|
1207 apply (erule xtr7, rule len_gt_0 [THEN dtle])+ |
|
1208 done |
|
1209 |
|
1210 lemma size_word_rsplit_rcat_size': |
|
1211 "word_rcat (ws :: 'a :: len word list) = frcw ==> |
|
1212 size frcw = length ws * len_of TYPE ('a) ==> |
|
1213 size (hd [word_rsplit frcw, ws]) = size ws" |
|
1214 apply (clarsimp simp add : word_size length_word_rsplit_exp_size') |
|
1215 apply (fast intro: given_quot_alt) |
|
1216 done |
|
1217 |
|
1218 lemmas size_word_rsplit_rcat_size = |
|
1219 size_word_rsplit_rcat_size' [simplified] |
|
1220 |
|
1221 lemma msrevs: |
|
1222 fixes n::nat |
|
1223 shows "0 < n \<Longrightarrow> (k * n + m) div n = m div n + k" |
|
1224 and "(k * n + m) mod n = m mod n" |
|
1225 by (auto simp: add_commute) |
|
1226 |
|
1227 lemma word_rsplit_rcat_size': |
|
1228 "word_rcat (ws :: 'a :: len word list) = frcw ==> |
|
1229 size frcw = length ws * len_of TYPE ('a) ==> word_rsplit frcw = ws" |
|
1230 apply (frule size_word_rsplit_rcat_size, assumption) |
|
1231 apply (clarsimp simp add : word_size) |
|
1232 apply (rule nth_equalityI, assumption) |
|
1233 apply clarsimp |
|
1234 apply (rule word_eqI) |
|
1235 apply (rule trans) |
|
1236 apply (rule test_bit_rsplit_alt) |
|
1237 apply (clarsimp simp: word_size)+ |
|
1238 apply (rule trans) |
|
1239 apply (rule test_bit_rcat [OF refl refl]) |
|
1240 apply (simp add : word_size msrevs) |
|
1241 apply (subst nth_rev) |
|
1242 apply arith |
|
1243 apply (simp add : le0 [THEN [2] xtr7, THEN diff_Suc_less]) |
|
1244 apply safe |
|
1245 apply (simp add : diff_mult_distrib) |
|
1246 apply (rule mpl_lem) |
|
1247 apply (cases "size ws") |
|
1248 apply simp_all |
|
1249 done |
|
1250 |
|
1251 lemmas word_rsplit_rcat_size = refl [THEN word_rsplit_rcat_size'] |
|
1252 |
|
1253 |
|
1254 subsection "Rotation" |
|
1255 |
|
1256 lemmas rotater_0' [simp] = rotater_def [where n = "0", simplified] |
|
1257 |
|
1258 lemmas word_rot_defs = word_roti_def word_rotr_def word_rotl_def |
|
1259 |
|
1260 lemma rotate_eq_mod: |
|
1261 "m mod length xs = n mod length xs ==> rotate m xs = rotate n xs" |
|
1262 apply (rule box_equals) |
|
1263 defer |
|
1264 apply (rule rotate_conv_mod [symmetric])+ |
|
1265 apply simp |
|
1266 done |
|
1267 |
|
1268 lemmas rotate_eqs [standard] = |
|
1269 trans [OF rotate0 [THEN fun_cong] id_apply] |
|
1270 rotate_rotate [symmetric] |
|
1271 rotate_id |
|
1272 rotate_conv_mod |
|
1273 rotate_eq_mod |
|
1274 |
|
1275 |
|
1276 subsubsection "Rotation of list to right" |
|
1277 |
|
1278 lemma rotate1_rl': "rotater1 (l @ [a]) = a # l" |
|
1279 unfolding rotater1_def by (cases l) auto |
|
1280 |
|
1281 lemma rotate1_rl [simp] : "rotater1 (rotate1 l) = l" |
|
1282 apply (unfold rotater1_def) |
|
1283 apply (cases "l") |
|
1284 apply (case_tac [2] "list") |
|
1285 apply auto |
|
1286 done |
|
1287 |
|
1288 lemma rotate1_lr [simp] : "rotate1 (rotater1 l) = l" |
|
1289 unfolding rotater1_def by (cases l) auto |
|
1290 |
|
1291 lemma rotater1_rev': "rotater1 (rev xs) = rev (rotate1 xs)" |
|
1292 apply (cases "xs") |
|
1293 apply (simp add : rotater1_def) |
|
1294 apply (simp add : rotate1_rl') |
|
1295 done |
|
1296 |
|
1297 lemma rotater_rev': "rotater n (rev xs) = rev (rotate n xs)" |
|
1298 unfolding rotater_def by (induct n) (auto intro: rotater1_rev') |
|
1299 |
|
1300 lemmas rotater_rev = rotater_rev' [where xs = "rev ys", simplified, standard] |
|
1301 |
|
1302 lemma rotater_drop_take: |
|
1303 "rotater n xs = |
|
1304 drop (length xs - n mod length xs) xs @ |
|
1305 take (length xs - n mod length xs) xs" |
|
1306 by (clarsimp simp add : rotater_rev rotate_drop_take rev_take rev_drop) |
|
1307 |
|
1308 lemma rotater_Suc [simp] : |
|
1309 "rotater (Suc n) xs = rotater1 (rotater n xs)" |
|
1310 unfolding rotater_def by auto |
|
1311 |
|
1312 lemma rotate_inv_plus [rule_format] : |
|
1313 "ALL k. k = m + n --> rotater k (rotate n xs) = rotater m xs & |
|
1314 rotate k (rotater n xs) = rotate m xs & |
|
1315 rotater n (rotate k xs) = rotate m xs & |
|
1316 rotate n (rotater k xs) = rotater m xs" |
|
1317 unfolding rotater_def rotate_def |
|
1318 by (induct n) (auto intro: funpow_swap1 [THEN trans]) |
|
1319 |
|
1320 lemmas rotate_inv_rel = le_add_diff_inverse2 [symmetric, THEN rotate_inv_plus] |
|
1321 |
|
1322 lemmas rotate_inv_eq = order_refl [THEN rotate_inv_rel, simplified] |
|
1323 |
|
1324 lemmas rotate_lr [simp] = rotate_inv_eq [THEN conjunct1, standard] |
|
1325 lemmas rotate_rl [simp] = |
|
1326 rotate_inv_eq [THEN conjunct2, THEN conjunct1, standard] |
|
1327 |
|
1328 lemma rotate_gal: "(rotater n xs = ys) = (rotate n ys = xs)" |
|
1329 by auto |
|
1330 |
|
1331 lemma rotate_gal': "(ys = rotater n xs) = (xs = rotate n ys)" |
|
1332 by auto |
|
1333 |
|
1334 lemma length_rotater [simp]: |
|
1335 "length (rotater n xs) = length xs" |
|
1336 by (simp add : rotater_rev) |
|
1337 |
|
1338 lemmas rrs0 = rotate_eqs [THEN restrict_to_left, |
|
1339 simplified rotate_gal [symmetric] rotate_gal' [symmetric], standard] |
|
1340 lemmas rrs1 = rrs0 [THEN refl [THEN rev_iffD1]] |
|
1341 lemmas rotater_eqs = rrs1 [simplified length_rotater, standard] |
|
1342 lemmas rotater_0 = rotater_eqs (1) |
|
1343 lemmas rotater_add = rotater_eqs (2) |
|
1344 |
|
1345 |
|
1346 subsubsection "map, map2, commuting with rotate(r)" |
|
1347 |
|
1348 lemma last_map: "xs ~= [] ==> last (map f xs) = f (last xs)" |
|
1349 by (induct xs) auto |
|
1350 |
|
1351 lemma butlast_map: |
|
1352 "xs ~= [] ==> butlast (map f xs) = map f (butlast xs)" |
|
1353 by (induct xs) auto |
|
1354 |
|
1355 lemma rotater1_map: "rotater1 (map f xs) = map f (rotater1 xs)" |
|
1356 unfolding rotater1_def |
|
1357 by (cases xs) (auto simp add: last_map butlast_map) |
|
1358 |
|
1359 lemma rotater_map: |
|
1360 "rotater n (map f xs) = map f (rotater n xs)" |
|
1361 unfolding rotater_def |
|
1362 by (induct n) (auto simp add : rotater1_map) |
|
1363 |
|
1364 lemma but_last_zip [rule_format] : |
|
1365 "ALL ys. length xs = length ys --> xs ~= [] --> |
|
1366 last (zip xs ys) = (last xs, last ys) & |
|
1367 butlast (zip xs ys) = zip (butlast xs) (butlast ys)" |
|
1368 apply (induct "xs") |
|
1369 apply auto |
|
1370 apply ((case_tac ys, auto simp: neq_Nil_conv)[1])+ |
|
1371 done |
|
1372 |
|
1373 lemma but_last_map2 [rule_format] : |
|
1374 "ALL ys. length xs = length ys --> xs ~= [] --> |
|
1375 last (map2 f xs ys) = f (last xs) (last ys) & |
|
1376 butlast (map2 f xs ys) = map2 f (butlast xs) (butlast ys)" |
|
1377 apply (induct "xs") |
|
1378 apply auto |
|
1379 apply (unfold map2_def) |
|
1380 apply ((case_tac ys, auto simp: neq_Nil_conv)[1])+ |
|
1381 done |
|
1382 |
|
1383 lemma rotater1_zip: |
|
1384 "length xs = length ys ==> |
|
1385 rotater1 (zip xs ys) = zip (rotater1 xs) (rotater1 ys)" |
|
1386 apply (unfold rotater1_def) |
|
1387 apply (cases "xs") |
|
1388 apply auto |
|
1389 apply ((case_tac ys, auto simp: neq_Nil_conv but_last_zip)[1])+ |
|
1390 done |
|
1391 |
|
1392 lemma rotater1_map2: |
|
1393 "length xs = length ys ==> |
|
1394 rotater1 (map2 f xs ys) = map2 f (rotater1 xs) (rotater1 ys)" |
|
1395 unfolding map2_def by (simp add: rotater1_map rotater1_zip) |
|
1396 |
|
1397 lemmas lrth = |
|
1398 box_equals [OF asm_rl length_rotater [symmetric] |
|
1399 length_rotater [symmetric], |
|
1400 THEN rotater1_map2] |
|
1401 |
|
1402 lemma rotater_map2: |
|
1403 "length xs = length ys ==> |
|
1404 rotater n (map2 f xs ys) = map2 f (rotater n xs) (rotater n ys)" |
|
1405 by (induct n) (auto intro!: lrth) |
|
1406 |
|
1407 lemma rotate1_map2: |
|
1408 "length xs = length ys ==> |
|
1409 rotate1 (map2 f xs ys) = map2 f (rotate1 xs) (rotate1 ys)" |
|
1410 apply (unfold map2_def) |
|
1411 apply (cases xs) |
|
1412 apply (cases ys, auto simp add : rotate1_def)+ |
|
1413 done |
|
1414 |
|
1415 lemmas lth = box_equals [OF asm_rl length_rotate [symmetric] |
|
1416 length_rotate [symmetric], THEN rotate1_map2] |
|
1417 |
|
1418 lemma rotate_map2: |
|
1419 "length xs = length ys ==> |
|
1420 rotate n (map2 f xs ys) = map2 f (rotate n xs) (rotate n ys)" |
|
1421 by (induct n) (auto intro!: lth) |
|
1422 |
|
1423 |
|
1424 -- "corresponding equalities for word rotation" |
|
1425 |
|
1426 lemma to_bl_rotl: |
|
1427 "to_bl (word_rotl n w) = rotate n (to_bl w)" |
|
1428 by (simp add: word_bl.Abs_inverse' word_rotl_def) |
|
1429 |
|
1430 lemmas blrs0 = rotate_eqs [THEN to_bl_rotl [THEN trans]] |
|
1431 |
|
1432 lemmas word_rotl_eqs = |
|
1433 blrs0 [simplified word_bl.Rep' word_bl.Rep_inject to_bl_rotl [symmetric]] |
|
1434 |
|
1435 lemma to_bl_rotr: |
|
1436 "to_bl (word_rotr n w) = rotater n (to_bl w)" |
|
1437 by (simp add: word_bl.Abs_inverse' word_rotr_def) |
|
1438 |
|
1439 lemmas brrs0 = rotater_eqs [THEN to_bl_rotr [THEN trans]] |
|
1440 |
|
1441 lemmas word_rotr_eqs = |
|
1442 brrs0 [simplified word_bl.Rep' word_bl.Rep_inject to_bl_rotr [symmetric]] |
|
1443 |
|
1444 declare word_rotr_eqs (1) [simp] |
|
1445 declare word_rotl_eqs (1) [simp] |
|
1446 |
|
1447 lemma |
|
1448 word_rot_rl [simp]: |
|
1449 "word_rotl k (word_rotr k v) = v" and |
|
1450 word_rot_lr [simp]: |
|
1451 "word_rotr k (word_rotl k v) = v" |
|
1452 by (auto simp add: to_bl_rotr to_bl_rotl word_bl.Rep_inject [symmetric]) |
|
1453 |
|
1454 lemma |
|
1455 word_rot_gal: |
|
1456 "(word_rotr n v = w) = (word_rotl n w = v)" and |
|
1457 word_rot_gal': |
|
1458 "(w = word_rotr n v) = (v = word_rotl n w)" |
|
1459 by (auto simp: to_bl_rotr to_bl_rotl word_bl.Rep_inject [symmetric] |
|
1460 dest: sym) |
|
1461 |
|
1462 lemma word_rotr_rev: |
|
1463 "word_rotr n w = word_reverse (word_rotl n (word_reverse w))" |
|
1464 by (simp add: word_bl.Rep_inject [symmetric] to_bl_word_rev |
|
1465 to_bl_rotr to_bl_rotl rotater_rev) |
|
1466 |
|
1467 lemma word_roti_0 [simp]: "word_roti 0 w = w" |
|
1468 by (unfold word_rot_defs) auto |
|
1469 |
|
1470 lemmas abl_cong = arg_cong [where f = "of_bl"] |
|
1471 |
|
1472 lemma word_roti_add: |
|
1473 "word_roti (m + n) w = word_roti m (word_roti n w)" |
|
1474 proof - |
|
1475 have rotater_eq_lem: |
|
1476 "\<And>m n xs. m = n ==> rotater m xs = rotater n xs" |
|
1477 by auto |
|
1478 |
|
1479 have rotate_eq_lem: |
|
1480 "\<And>m n xs. m = n ==> rotate m xs = rotate n xs" |
|
1481 by auto |
|
1482 |
|
1483 note rpts [symmetric, standard] = |
|
1484 rotate_inv_plus [THEN conjunct1] |
|
1485 rotate_inv_plus [THEN conjunct2, THEN conjunct1] |
|
1486 rotate_inv_plus [THEN conjunct2, THEN conjunct2, THEN conjunct1] |
|
1487 rotate_inv_plus [THEN conjunct2, THEN conjunct2, THEN conjunct2] |
|
1488 |
|
1489 note rrp = trans [symmetric, OF rotate_rotate rotate_eq_lem] |
|
1490 note rrrp = trans [symmetric, OF rotater_add [symmetric] rotater_eq_lem] |
|
1491 |
|
1492 show ?thesis |
|
1493 apply (unfold word_rot_defs) |
|
1494 apply (simp only: split: split_if) |
|
1495 apply (safe intro!: abl_cong) |
|
1496 apply (simp_all only: to_bl_rotl [THEN word_bl.Rep_inverse'] |
|
1497 to_bl_rotl |
|
1498 to_bl_rotr [THEN word_bl.Rep_inverse'] |
|
1499 to_bl_rotr) |
|
1500 apply (rule rrp rrrp rpts, |
|
1501 simp add: nat_add_distrib [symmetric] |
|
1502 nat_diff_distrib [symmetric])+ |
|
1503 done |
|
1504 qed |
|
1505 |
|
1506 lemma word_roti_conv_mod': "word_roti n w = word_roti (n mod int (size w)) w" |
|
1507 apply (unfold word_rot_defs) |
|
1508 apply (cut_tac y="size w" in gt_or_eq_0) |
|
1509 apply (erule disjE) |
|
1510 apply simp_all |
|
1511 apply (safe intro!: abl_cong) |
|
1512 apply (rule rotater_eqs) |
|
1513 apply (simp add: word_size nat_mod_distrib) |
|
1514 apply (simp add: rotater_add [symmetric] rotate_gal [symmetric]) |
|
1515 apply (rule rotater_eqs) |
|
1516 apply (simp add: word_size nat_mod_distrib) |
|
1517 apply (rule int_eq_0_conv [THEN iffD1]) |
|
1518 apply (simp only: zmod_int zadd_int [symmetric]) |
|
1519 apply (simp add: rdmods) |
|
1520 done |
|
1521 |
|
1522 lemmas word_roti_conv_mod = word_roti_conv_mod' [unfolded word_size] |
|
1523 |
|
1524 |
|
1525 subsubsection "Word rotation commutes with bit-wise operations" |
|
1526 |
|
1527 (* using locale to not pollute lemma namespace *) |
|
1528 locale word_rotate |
|
1529 |
|
1530 context word_rotate |
|
1531 begin |
|
1532 |
|
1533 lemmas word_rot_defs' = to_bl_rotl to_bl_rotr |
|
1534 |
|
1535 lemmas blwl_syms [symmetric] = bl_word_not bl_word_and bl_word_or bl_word_xor |
|
1536 |
|
1537 lemmas lbl_lbl = trans [OF word_bl.Rep' word_bl.Rep' [symmetric]] |
|
1538 |
|
1539 lemmas ths_map2 [OF lbl_lbl] = rotate_map2 rotater_map2 |
|
1540 |
|
1541 lemmas ths_map [where xs = "to_bl v", standard] = rotate_map rotater_map |
|
1542 |
|
1543 lemmas th1s [simplified word_rot_defs' [symmetric]] = ths_map2 ths_map |
|
1544 |
|
1545 lemma word_rot_logs: |
|
1546 "word_rotl n (NOT v) = NOT word_rotl n v" |
|
1547 "word_rotr n (NOT v) = NOT word_rotr n v" |
|
1548 "word_rotl n (x AND y) = word_rotl n x AND word_rotl n y" |
|
1549 "word_rotr n (x AND y) = word_rotr n x AND word_rotr n y" |
|
1550 "word_rotl n (x OR y) = word_rotl n x OR word_rotl n y" |
|
1551 "word_rotr n (x OR y) = word_rotr n x OR word_rotr n y" |
|
1552 "word_rotl n (x XOR y) = word_rotl n x XOR word_rotl n y" |
|
1553 "word_rotr n (x XOR y) = word_rotr n x XOR word_rotr n y" |
|
1554 by (rule word_bl.Rep_eqD, |
|
1555 rule word_rot_defs' [THEN trans], |
|
1556 simp only: blwl_syms [symmetric], |
|
1557 rule th1s [THEN trans], |
|
1558 rule refl)+ |
|
1559 end |
|
1560 |
|
1561 lemmas word_rot_logs = word_rotate.word_rot_logs |
|
1562 |
|
1563 lemmas bl_word_rotl_dt = trans [OF to_bl_rotl rotate_drop_take, |
|
1564 simplified word_bl.Rep', standard] |
|
1565 |
|
1566 lemmas bl_word_rotr_dt = trans [OF to_bl_rotr rotater_drop_take, |
|
1567 simplified word_bl.Rep', standard] |
|
1568 |
|
1569 lemma bl_word_roti_dt': |
|
1570 "n = nat ((- i) mod int (size (w :: 'a :: len word))) ==> |
|
1571 to_bl (word_roti i w) = drop n (to_bl w) @ take n (to_bl w)" |
|
1572 apply (unfold word_roti_def) |
|
1573 apply (simp add: bl_word_rotl_dt bl_word_rotr_dt word_size) |
|
1574 apply safe |
|
1575 apply (simp add: zmod_zminus1_eq_if) |
|
1576 apply safe |
|
1577 apply (simp add: nat_mult_distrib) |
|
1578 apply (simp add: nat_diff_distrib [OF pos_mod_sign pos_mod_conj |
|
1579 [THEN conjunct2, THEN order_less_imp_le]] |
|
1580 nat_mod_distrib) |
|
1581 apply (simp add: nat_mod_distrib) |
|
1582 done |
|
1583 |
|
1584 lemmas bl_word_roti_dt = bl_word_roti_dt' [unfolded word_size] |
|
1585 |
|
1586 lemmas word_rotl_dt = bl_word_rotl_dt |
|
1587 [THEN word_bl.Rep_inverse' [symmetric], standard] |
|
1588 lemmas word_rotr_dt = bl_word_rotr_dt |
|
1589 [THEN word_bl.Rep_inverse' [symmetric], standard] |
|
1590 lemmas word_roti_dt = bl_word_roti_dt |
|
1591 [THEN word_bl.Rep_inverse' [symmetric], standard] |
|
1592 |
|
1593 lemma word_rotx_0 [simp] : "word_rotr i 0 = 0 & word_rotl i 0 = 0" |
|
1594 by (simp add : word_rotr_dt word_rotl_dt to_bl_0 replicate_add [symmetric]) |
|
1595 |
|
1596 lemma word_roti_0' [simp] : "word_roti n 0 = 0" |
|
1597 unfolding word_roti_def by auto |
|
1598 |
|
1599 lemmas word_rotr_dt_no_bin' [simp] = |
|
1600 word_rotr_dt [where w="number_of w", unfolded to_bl_no_bin, standard] |
|
1601 |
|
1602 lemmas word_rotl_dt_no_bin' [simp] = |
|
1603 word_rotl_dt [where w="number_of w", unfolded to_bl_no_bin, standard] |
|
1604 |
|
1605 declare word_roti_def [simp] |
|
1606 |
|
1607 end |
|
1608 |
|