-
Notifications
You must be signed in to change notification settings - Fork 0
/
gf2xe.f90
1146 lines (1034 loc) · 24.4 KB
/
gf2xe.f90
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
module gf2xe
!===============================================================================
! Fortran 90/95 Module for GF(2)[x] computation
!===============================================================================
use mt_kind_defs
implicit none
private
public :: gf2x_obj
public :: gf2x_prime_obj
public :: new,delete
public :: print_bit,print_hex
public :: get_deg
public :: set_coef, set_prime
public :: assign
public :: add, add_assign
public :: mult, mult_assign
public :: pow, square
public :: div, rem, divrem
public :: mult_by_x, div_by_x, mod_by_x
public :: shift
public :: deg_i32, mult_i32, square_i32, shift_i32
public :: mult_i32_old
public :: gf2x_pow_pow_2
integer(INT32), parameter :: MAX_KARA = 64
type gf2x_obj
integer(INT32), pointer :: c(:) => NULL()
integer(INT32) :: deg = -1
integer(INT32) :: size = -1
end type
type gf2x_prime_obj
type(gf2x_obj) :: prime_poly
type(gf2x_obj) :: barrett_poly
integer(INT32) :: deg
end type
interface new
module procedure gf2x_new
module procedure gf2x_delete_prime
end interface
interface delete
module procedure gf2x_delete
module procedure gf2x_delete_prime
end interface
interface print_bit
module procedure gf2x_print_bit
end interface
interface print_hex
module procedure gf2x_print_hex
end interface
interface set_coef
module procedure gf2x_set_coef
end interface
interface set_prime
module procedure gf2x_set_prime
end interface
interface assign
module procedure gf2x_assign
end interface
interface add
module procedure gf2x_add
end interface
interface add_assign
module procedure gf2x_add_assign
end interface
interface mult
module procedure gf2x_mult_kara
end interface
interface mult_assign
module procedure gf2x_mult_assign_kara
end interface
interface pow
module procedure gf2x_pow
module procedure gf2x_pow_mod
end interface
interface square
module procedure gf2x_square
end interface
interface mult_by_x
module procedure gf2x_mult_by_x
end interface
interface mod_by_x
module procedure gf2x_mod_by_x
end interface
interface div_by_x
module procedure gf2x_div_by_x
end interface
interface div
module procedure gf2x_div
end interface
interface rem
module procedure gf2x_rem
module procedure gf2x_rem_barrett
end interface
interface divrem
module procedure gf2x_divrem
end interface
interface shift
module procedure gf2x_shift
end interface
contains
!!DEC$ ATTRIBUTES FORCEINLINE :: get_size
function get_size(deg) result(size)
integer(INT32) :: deg,size
size = CEILING(real(deg+1,kind=REAL64)/32.0_REAL64)
return
end function
subroutine gf2x_new(this,deg)
type(gf2x_obj), intent(inout) :: this
integer(INT32), intent(in) :: deg
integer(INT32) :: isize
intrinsic :: SIZE
if (deg < 0) then
this%deg = -1
this%size = -1
return
endif
isize = get_size(deg)
this%size = isize
this%deg = deg
if (.not.associated(this%c)) then
allocate(this%c(0:isize-1))
else
if (SIZE(this%c) < this%size) then
deallocate(this%c)
NULLIFY(this%c)
allocate(this%c(0:isize-1))
endif
endif
this%c(:) = 0
return
end subroutine
subroutine gf2x_delete(this)
type(gf2x_obj), intent(inout) :: this
integer(INT32) :: ierr
if (associated(this%c)) then
deallocate(this%c,STAT=ierr)
endif
NULLIFY(this%c)
this%deg = -1
this%size = -1
return
end subroutine
subroutine gf2x_print_bit(this)
type(gf2x_obj), intent(in) :: this
integer(INT32) :: i,ib,iw,deg
deg = get_deg(this)
if (deg < 0) then
write(*,'("0")')
return
endif
do i=deg,0,-1
ib = mod(i,32)
iw = i/32
if (BTEST(this%c(iw),ib)) then
write(*,'("1",$)')
else
write(*,'("0",$)')
endif
enddo
write(*,'("")')
return
end subroutine
subroutine gf2x_print_hex(this)
type(gf2x_obj), intent(in) :: this
integer(INT32) :: i,ib,iw,isize
character(9) :: str
if (is_zero(this)) then
write(*,'("0")')
return
endif
isize = get_size(this%deg)
i = isize-1
write(str,'(Z8)')this%c(i)
write(*,'(A,$)')TRIM(ADJUSTL(str))
do i=isize-2,0,-1
write(*,'(Z8.8,$)')this%c(i)
enddo
write(*,'("")')
return
end subroutine
subroutine gf2x_assign(c,a)
type(gf2x_obj), intent(inout) :: c ! c := a
type(gf2x_obj), intent(in) :: a
integer(INT32) :: ia,isa,i
call delete(c)
if (is_zero(a)) then
return
endif
ia = get_deg(a)
isa = get_size(ia)
call new(c,ia)
do i=0,isa-1
c%c(i) = a%c(i)
enddo
return
end subroutine
function is_zero(a) result(is)
type(gf2x_obj), intent(in) :: a
logical :: is
integer(INT32) :: deg
deg = get_deg(a)
if (deg==-1) then
is = .true.
else
is = .false.
endif
return
end function
!!DEC$ ATTRIBUTES FORCEINLINE :: get_deg
function get_deg(a) result(deg)
type(gf2x_obj), intent(in) :: a
integer(INT32) :: deg
integer(INT32) :: isize,i,top_deg
intrinsic :: SIZE
deg=-1
if (.not.associated(a%c)) return
isize = SIZE(a%c)
do i=isize-1,0,-1
if (a%c(i) /= 0) then
top_deg = deg_i32(a%c(i))
deg = 32*i + top_deg
return
endif
enddo
return
end function
subroutine gf2x_set_coef(a,i)
type(gf2x_obj), intent(inout) :: a
integer(INT32), intent(in) :: i
type(gf2x_obj), pointer :: w
integer(INT32) :: ib,iw
NULLIFY(w)
if (is_zero(a)) then
call new(a,i)
endif
allocate(w)
call new(w,i)
iw = i/32
ib = mod(i,32)
w%c(iw) = ibset(w%c(iw),ib)
call add_assign(w,a) ! w := w + a
call assign(a,w) ! a := w
call delete(w)
deallocate(w)
NULLIFY(w)
a%deg = get_deg(a)
return
end subroutine
subroutine gf2x_add_assign(c,a)
type(gf2x_obj), intent(inout) :: c ! c := c + a
type(gf2x_obj), intent(in) :: a
type(gf2x_obj), pointer :: w
integer(INT32) :: ia,ic
integer(INT32) :: isa,isc,i
if (is_zero(a)) then
return
endif
if (is_zero(c)) then
call assign(c,a)
return
endif
ia = a%deg
ic = c%deg
isa = a%size
isc = c%size
if (isc < isa) then
NULLIFY(w)
allocate(w)
call new(w,MAX(ia,ic))
do i=0,isc-1
w%c(i) = IEOR(c%c(i),a%c(i))
enddo
do i=isc,isa-1
w%c(i) = a%c(i)
enddo
call assign(c,w)
call delete(w)
deallocate(w)
NULLIFY(w)
else
do i=0,isa-1
c%c(i) = IEOR(c%c(i),a%c(i))
enddo
c%deg = get_deg(c)
c%size = get_size(c%deg)
endif
return
end subroutine
subroutine gf2x_add(c,a,b)
type(gf2x_obj), intent(inout) :: c ! c := a + b
type(gf2x_obj), intent(in) :: a,b
integer(INT32) :: ia,ib,ic
integer(INT32) :: isa,isb,isc,i
if (is_zero(a) .and. is_zero(b)) then
return
endif
if (is_zero(a)) then
call assign(c,b)
return
endif
if (is_zero(b)) then
call assign(c,a)
return
endif
ia = get_deg(a)
ib = get_deg(b)
isa = get_size(ia)
isb = get_size(ib)
if (c%deg < MAX(ia,ib)) call new(c,MAX(ia,ib))
if (isa < isb) then
do i=0,isa-1
c%c(i) = IEOR(a%c(i),b%c(i))
enddo
do i=isa,isb-1
c%c(i) = b%c(i)
enddo
else
do i=0,isb-1
c%c(i) = IEOR(a%c(i),b%c(i))
enddo
do i=isb,isa-1
c%c(i) = a%c(i)
enddo
endif
c%deg = get_deg(c)
c%size = get_size(c%deg)
return
end subroutine
subroutine gf2x_pow(c,a,e)
type(gf2x_obj), intent(inout) :: c ! c = a**e
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: e
type(gf2x_obj), pointer :: w
integer(INT32) :: ch,cl
integer(INT32) :: i,deg
NULLIFY(w)
call delete(c)
if (e==1) then
call assign(c,a)
return
endif
if (e==0) then
call set_coef(c,0)
return
endif
if (e<0) then
write(*,*)"pow: c = a^e : exponent should be e>=0."
stop
endif
if (is_zero(a)) return
deg = deg_i32(e)
allocate(w)
call set_coef(c,0)
do i=deg,0,-1
call square(w,c) ! w := c**2
if (BTEST(e,i)) then
call mult(c,w,a) ! c := w * a
else
call assign(c,w) ! c := w
endif
enddo
call delete(w)
deallocate(w)
NULLIFY(w)
return
end subroutine
subroutine gf2x_square(c,a)
type(gf2x_obj), intent(inout) :: c ! c := a**2
type(gf2x_obj), intent(in) :: a
integer(INT32) :: ch,cl
integer(INT32) :: i,deg
call delete(c)
if (is_zero(a)) return
deg = a%deg*2
call new(c,deg)
do i=0,a%size-1
if (a%c(i) == 0) cycle
call square_i32(a%c(i),ch,cl)
if (cl /= 0) c%c(2*i) = IEOR(c%c(2*i), cl)
if (ch /= 0) c%c(2*i+1) = IEOR(c%c(2*i+1),ch)
enddo
c%deg = get_deg(c)
c%size = get_size(c%deg)
return
end subroutine
recursive subroutine gf2x_mult_kara(c,a,b)
!
! multiply 2 polyomials using Karatsuba algorithm
!
type(gf2x_obj), intent(inout) :: c ! c := a * b
type(gf2x_obj), intent(in) :: a,b
type(gf2x_obj), pointer :: ah,al,bh,bl,ahbh,albl,ahl,bhl,ahlbhl
integer(INT32) :: isa,isb,isc
integer(INT32) :: i,j,deg
NULLIFY(ah,al,bh,bl,ahbh,albl,ahl,bhl,ahlbhl)
call delete(c)
if (is_zero(a)) return
if (is_zero(b)) return
isa = a%size
isb = b%size
isc = MAX(isa,isb)
if (isc < MAX_KARA) then
call gf2x_mult_normal(c,a,b)
return
endif
if (mod(isc,2)/=0) then
isc = isc + 1
endif
allocate(ah,al,bh,bl,ahbh,albl,ahl,bhl,ahlbhl)
deg = 32*(isc/2)-1
call new(al,deg)
call new(bl,deg)
call new(ah,deg)
call new(bh,deg)
do i=0,MIN(isc/2-1,isa-1)
al%c(i) = a%c(i)
enddo
do i=0,MIN(isc/2-1,isb-1)
bl%c(i) = b%c(i)
enddo
do i=isc/2,isa-1
ah%c(i-isc/2) = a%c(i)
enddo
do i=isc/2,isb-1
bh%c(i-isc/2) = b%c(i)
enddo
ah%deg = get_deg(ah)
al%deg = get_deg(al)
bh%deg = get_deg(bh)
bl%deg = get_deg(bl)
ah%size = get_size(ah%deg)
al%size = get_size(al%deg)
bh%size = get_size(bh%deg)
bl%size = get_size(bl%deg)
!===================================
call add(ahl,ah,al)
call add(bhl,bh,bl)
call gf2x_mult_kara(ahlbhl,ahl,bhl)
call delete(ahl)
call delete(bhl)
deallocate(ahl,bhl)
!===================================
call gf2x_mult_kara(ahbh,ah,bh)
call delete(ah)
call delete(bh)
deallocate(ah,bh)
call add_assign(ahlbhl,ahbh)
!===================================
call gf2x_mult_kara(albl,al,bl)
call delete(al)
call delete(bl)
deallocate(al,bl)
call add_assign(ahlbhl,albl)
!===================================
deg = a%deg + b%deg
call new(c,deg)
do i=0,MIN(c%size,albl%size)-1
c%c(i) = albl%c(i)
enddo
call delete(albl)
if (.not. is_zero(ahlbhl)) then
do i=isc/2,MIN(c%size,isc/2+ahlbhl%size)-1
c%c(i) = IEOR(c%c(i),ahlbhl%c(i-isc/2))
enddo
endif
call delete(ahlbhl)
if (.not. is_zero(ahbh)) then
do i=isc,MIN(c%size,isc+ahbh%size)-1
c%c(i) = IEOR(c%c(i),ahbh%c(i-isc))
enddo
endif
call delete(ahbh)
deallocate(ahbh,albl,ahlbhl)
NULLIFY(ah,al,bh,bl,ahbh,albl,ahl,bhl,ahlbhl)
c%deg = get_deg(c)
c%size = get_size(c%deg)
return
end subroutine
subroutine gf2x_mult_assign_kara(a,b)
type(gf2x_obj), intent(inout) :: a ! a := a * b
type(gf2x_obj), intent(in) :: b
type(gf2x_obj), pointer :: w
NULLIFY(w)
if (is_zero(a)) then
call delete(a)
return
endif
if (is_zero(b)) then
call delete(a)
return
endif
allocate(w)
call gf2x_mult_kara(w,a,b)
call assign(a,w)
call delete(w)
deallocate(w)
NULLIFY(w)
return
end subroutine
subroutine gf2x_mult_assign_normal(a,b)
type(gf2x_obj), intent(inout) :: a ! a := a * b
type(gf2x_obj), intent(in) :: b
type(gf2x_obj), pointer :: w
integer(INT32) :: ch,cl
integer(INT32) :: i,j,deg
NULLIFY(w)
allocate(w)
deg = a%deg + b%deg
call new(w,deg)
call gf2x_mult_normal(w,a,b)
call assign(a,w) ! a := w
call delete(w)
deallocate(w)
NULLIFY(w)
return
end subroutine
subroutine gf2x_mult_normal(c,a,b)
type(gf2x_obj), intent(inout) :: c ! c := a * b
type(gf2x_obj), intent(in) :: a,b
integer(INT32) :: ch,cl
integer(INT32) :: i,j,ij,deg,kk,mm
integer(INT32), allocatable :: hi(:,:),lo(:,:)
call delete(c)
if (is_zero(a) .or. is_zero(b) ) then
return
endif
deg = a%deg + b%deg
call new(c,deg)
!#define _NEW_
!#undef _NEW_
!#ifdef _NEW_
! do j=0,c%size-2
! kk = MIN(j, a%size-1)
! mm = MAX(0,j-b%size+1)
! do i=mm,kk
! call mult_i32(a%c(i),b%c(j-i),ch,cl)
! c%c(j) = IEOR(c%c(j), cl)
! c%c(j+1) = IEOR(c%c(j+1),ch)
! enddo
! enddo
! j=c%size-1
! kk = a%size-1
! mm = c%size-b%size
! do i=mm,kk
! call mult_i32(a%c(i),b%c(j-i),ch,cl)
! c%c(j) = IEOR(c%c(j), cl)
! enddo
!
!#else
do j=0,b%size-1
if (b%c(j) == 0) cycle
do i=0,a%size-1
if (a%c(i) == 0) cycle
ij = i + j
call mult_i32(a%c(i),b%c(j),ch,cl)
c%c(ij) = IEOR(c%c(ij), cl)
if (ij+1<c%size) c%c(ij+1) = IEOR(c%c(ij+1),ch)
enddo
enddo
!#endif
c%deg = get_deg(c)
c%size = get_size(c%deg)
return
end subroutine
subroutine gf2x_shift(c,a,i)
type(gf2x_obj), intent(inout) :: c ! c := shift(a,i)
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: i
integer(INT32) :: j,isn,iw,ib,ida,isa,ch,cm,cl
if (i==0) then
call assign(c,a)
return
endif
ida = get_deg(a)
isa = get_size(ida)
if (ida + i < 0) then
call delete(c)
return
endif
iw = abs(i)/32
ib = mod(abs(i),32)
call delete(c)
call new(c,ida+i)
if (i > 0) then
do j=0,isa-1
call shift_i32(a%c(j),+ib,ch,cm,cl)
if (ch /= 0) c%c(j+iw+1) = IEOR(c%c(j+iw+1),ch)
if (cm /= 0) c%c(j+iw) = IEOR(c%c(j+iw) ,cm)
enddo
else
call shift_i32(a%c(iw),-ib,ch,cm,cl)
if (cm /= 0) c%c(0) = IEOR(c%c(0),cm)
do j=iw+1,isa-1
call shift_i32(a%c(j),-ib,ch,cm,cl)
if (cm /= 0) c%c(j-iw) = IEOR(c%c(j-iw) ,cm)
if (cl /= 0) c%c(j-iw-1) = IEOR(c%c(j-iw-1),cl)
enddo
endif
c%deg = get_deg(c)
c%size = get_size(c%deg)
return
end subroutine
subroutine gf2x_divrem(q,r,a,b)
! a =: q * b + r
type(gf2x_obj), intent(inout) :: q ! q := a div b
type(gf2x_obj), intent(inout) :: r ! r := a mod b
type(gf2x_obj), intent(in) :: a,b
type(gf2x_obj), pointer :: w,t,s
integer(INT32) :: ida,idb,idw
call delete(q)
call delete(r)
ida = a%deg
idb = b%deg
if (ida < idb) then
call assign(r,a)
return
endif
NULLIFY(w,t,s)
allocate(w,t,s)
call assign(w,a)
idw = w%deg
do
call mult_by_x(t,b,idw-idb) ! t := b * x^(deg(w)-deg(b))
call set_coef(s,idw-idb) ! s := s + x^(deg(w)-deg(b))
call add_assign(w,t) ! w := w + t
call delete(t)
idw = w%deg
if (idw < idb) exit
enddo
call assign(r,w)
call delete(w)
call assign(q,s)
call delete(s)
deallocate(w,t,s)
NULLIFY(w,t,s)
return
end subroutine
subroutine gf2x_div(q,a,b)
! a =: q * b + r
type(gf2x_obj), intent(inout) :: q ! q := a div b
type(gf2x_obj), intent(in) :: a,b
type(gf2x_obj), pointer :: w,t,s
integer(INT32) :: ida,idb,idw
call delete(q)
ida = a%deg
idb = b%deg
if (ida < idb) then
return
endif
NULLIFY(w,t,s)
allocate(w,t,s)
call assign(w,a)
idw = w%deg
do
call mult_by_x(t,b,idw-idb) ! t := b * x^(deg(w)-deg(b))
call set_coef(s,idw-idb) ! s := s + x^(deg(w)-deg(b))
call add_assign(w,t) ! w := w + t
call delete(t)
idw = w%deg
if (idw < idb) exit
enddo
call delete(w)
call assign(q,s)
call delete(s)
deallocate(w,t,s)
NULLIFY(w,t,s)
return
end subroutine
subroutine gf2x_rem(r,a,b)
type(gf2x_obj), intent(inout) :: r ! r := a mod b
type(gf2x_obj), intent(in) :: a,b
type(gf2x_obj), pointer :: w,t
integer(INT32) :: ida,idb,idw
call delete(r)
ida = a%deg
idb = b%deg
if (ida < idb) then
call assign(r,a)
return
endif
NULLIFY(w,t)
allocate(w,t)
call assign(w,a)
idw = w%deg
do
call mult_by_x(t,b,idw-idb) ! t := b * x^(deg(w)-deg(b))
call add_assign(w,t) ! w := w + t
call delete(t)
idw = w%deg
if (idw < idb) exit
enddo
call assign(r,w)
call delete(w)
deallocate(w,t)
NULLIFY(w,t)
return
end subroutine
subroutine gf2x_set_prime(mp,m)
!
! Set a primitive polynomial to the cotainer.
! the container contains the prime poly and precomputed polynomial for Barrett reduciont.
! This routine does not check the primitivity.
! mp : container
! m : primitive polynomial
!
type(gf2x_prime_obj), intent(inout) :: mp
type(gf2x_obj), intent(in) :: m
type(gf2x_obj), pointer :: xx
integer(INT32) :: deg
call delete(mp)
call assign(mp%prime_poly,m)
deg = get_deg(m)
mp%deg = deg
NULLIFY(xx)
allocate(xx)
call set_coef(xx,2*deg)
call div(mp%barrett_poly,xx,m)
call delete(xx)
deallocate(xx)
NULLIFY(xx)
return
end subroutine
subroutine gf2x_delete_prime(mp)
type(gf2x_prime_obj), intent(inout) :: mp
call delete(mp%prime_poly)
call delete(mp%barrett_poly)
return
end subroutine
subroutine gf2x_rem_barrett(r,a,m)
!
! compute r := a mod m using Barrett algorithm
!
type(gf2x_obj), intent(inout) :: r ! r := a mod m
type(gf2x_obj), intent(in) :: a
type(gf2x_prime_obj), intent(in) :: m ! precomputed polynomial for Barrett algorithm
type(gf2x_obj), pointer :: q,p
integer(INT32) :: deg
call delete(r)
deg = m%deg
if (a%deg < deg) then
call assign(r,a)
return
endif
NULLIFY(q,p)
allocate(q,p)
call div_by_x(q,a,deg) ! q = a / x**deg
call mod_by_x(r,a,deg) ! r = a mod x**deg
call mult_assign(q,m%barrett_poly) ! q = q * mu
call div_by_x(p,q,deg) ! p = q / x**deg
call mult_assign(p,m%prime_poly) ! p = p * m
call mod_by_x(q,p,deg) ! q = p mod x**deg
call add_assign(r,q) ! r = r + q
call delete(p)
call delete(q)
deallocate(p,q)
NULLIFY(p,q)
return
end subroutine
subroutine gf2x_mod_by_x(c,a,i)
type(gf2x_obj), intent(inout) :: c ! c := a mod x^i
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: i
type(gf2x_obj), pointer :: w
integer(INT32) :: iw,ib,j
call delete(c)
if (a%deg < i) then
call assign(c,a)
return
endif
if (i == 0) then
call delete(c)
return
endif
if (i < 0) then
write(*,'("mod_by_x: error, negative i:",I10)')i
stop
endif
iw = i/32
ib = mod(i,32)
NULLIFY(w)
allocate(w)
call new(w,i)
do j=0,w%size-1
w%c(j) = a%c(j)
enddo
w%c(w%size-1) = IAND(w%c(w%size-1),2**ib-1)
call assign(c,w)
call delete(w)
deallocate(w)
NULLIFY(w)
return
end subroutine
subroutine gf2x_mult_by_x(c,a,i)
type(gf2x_obj), intent(inout) :: c ! c := a * x^i
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: i
if (i < 0) then
write(*,'("mult_by_x: error, negative i:",I10)')i
stop
endif
if (i == 0) then
call assign(c,a)
return
endif
call shift(c,a,i)
return
end subroutine
subroutine gf2x_div_by_x(c,a,i)
type(gf2x_obj), intent(inout) :: c ! c := a div x^i
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: i
if (i < 0) then
write(*,'("div_by_x: error, negative i:",I10)')i
stop
endif
if (i == 0) then
call assign(c,a)
return
endif
call shift(c,a,-i)
return
end subroutine
subroutine gf2x_pow_pow_2(c,e,m)
type(gf2x_obj), intent(inout) :: c ! c := x**(2**e) mod m
integer(INT32), intent(in) :: e
type(gf2x_prime_obj), intent(in) :: m ! precomputed polynomial for Barrett algorithm
integer(INT32) :: i,ee
type(gf2x_obj), pointer :: w,s
ee = CEILING(log(REAL(m%deg))/log(2.0))
call delete(c)
if (ee > e) then
call set_coef(c,2**e)
return
endif
NULLIFY(w,s)
allocate(w,s)
call set_coef(w,2**ee)
call rem(s,w,m) ! s = w mod m
do i=ee+1,e
call square(w,s) ! w = s**2
call rem(s,w,m) ! s = w mod m
enddo
call assign(c,s)
call delete(w)
call delete(s)
deallocate(w,s)
NULLIFY(w,s)
return
end subroutine
subroutine gf2x_pow_mod(c,a,e,m)
type(gf2x_obj), intent(inout) :: c ! c := a**e mod m
type(gf2x_obj), intent(in) :: a
integer(INT32), intent(in) :: e
type(gf2x_prime_obj), intent(in) :: m ! precomputed polynomial for Barrett algorithm
type(gf2x_obj), pointer :: w
integer(INT32) :: i,deg
NULLIFY(w)
call delete(c)
if (e==1) then
if (a%deg >= m%deg) then
call rem(c,a,m)
return
else
call assign(c,a)
return
endif
endif
if (e==0) then
call set_coef(c,0)
return
endif
if (e<0) then
write(*,*)"pow: c = a^e mod m : exponent should be e>=0."
stop
endif
if (is_zero(a)) return
deg = deg_i32(e)
allocate(w)
call set_coef(c,0)
do i=deg,0,-1
call square(w,c) ! c := c**2 mod m
call rem(c,w,m)
if (BTEST(e,i)) then
call mult(w,c,a) ! c := c * a mod m
call rem(c,w,m)
endif
enddo
call delete(w)
deallocate(w)
NULLIFY(w)
return
end subroutine
!========================================================================
function deg_i32(a) result(d)
integer(INT32) :: a,d,i
d=-1
do i=31,0,-1
if (BTEST(a,i)) then
d=i
exit
endif
enddo
return