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Alexandre Savard1b09e312012-08-07 20:33:29 -04001#!/usr/local/bin/perl
2
3push(@INC,"perlasm","../../perlasm");
4require "x86asm.pl";
5require "cbc.pl";
6
7&asm_init($ARGV[0],"bf-686.pl");
8
9$BF_ROUNDS=16;
10$BF_OFF=($BF_ROUNDS+2)*4;
11$L="ecx";
12$R="edx";
13$P="edi";
14$tot="esi";
15$tmp1="eax";
16$tmp2="ebx";
17$tmp3="ebp";
18
19&des_encrypt("BF_encrypt",1);
20&des_encrypt("BF_decrypt",0);
21&cbc("BF_cbc_encrypt","BF_encrypt","BF_decrypt",1,4,5,3,-1,-1);
22
23&asm_finish();
24
25&file_end();
26
27sub des_encrypt
28 {
29 local($name,$enc)=@_;
30
31 &function_begin($name,"");
32
33 &comment("");
34 &comment("Load the 2 words");
35 &mov("eax",&wparam(0));
36 &mov($L,&DWP(0,"eax","",0));
37 &mov($R,&DWP(4,"eax","",0));
38
39 &comment("");
40 &comment("P pointer, s and enc flag");
41 &mov($P,&wparam(1));
42
43 &xor( $tmp1, $tmp1);
44 &xor( $tmp2, $tmp2);
45
46 # encrypting part
47
48 if ($enc)
49 {
50 &xor($L,&DWP(0,$P,"",0));
51 for ($i=0; $i<$BF_ROUNDS; $i+=2)
52 {
53 &comment("");
54 &comment("Round $i");
55 &BF_ENCRYPT($i+1,$R,$L,$P,$tot,$tmp1,$tmp2,$tmp3);
56
57 &comment("");
58 &comment("Round ".sprintf("%d",$i+1));
59 &BF_ENCRYPT($i+2,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3);
60 }
61 &xor($R,&DWP(($BF_ROUNDS+1)*4,$P,"",0));
62
63 &mov("eax",&wparam(0));
64 &mov(&DWP(0,"eax","",0),$R);
65 &mov(&DWP(4,"eax","",0),$L);
66 &function_end_A($name);
67 }
68 else
69 {
70 &xor($L,&DWP(($BF_ROUNDS+1)*4,$P,"",0));
71 for ($i=$BF_ROUNDS; $i>0; $i-=2)
72 {
73 &comment("");
74 &comment("Round $i");
75 &BF_ENCRYPT($i,$R,$L,$P,$tot,$tmp1,$tmp2,$tmp3);
76 &comment("");
77 &comment("Round ".sprintf("%d",$i-1));
78 &BF_ENCRYPT($i-1,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3);
79 }
80 &xor($R,&DWP(0,$P,"",0));
81
82 &mov("eax",&wparam(0));
83 &mov(&DWP(0,"eax","",0),$R);
84 &mov(&DWP(4,"eax","",0),$L);
85 &function_end_A($name);
86 }
87
88 &function_end_B($name);
89 }
90
91sub BF_ENCRYPT
92 {
93 local($i,$L,$R,$P,$tot,$tmp1,$tmp2,$tmp3)=@_;
94
95 &rotr( $R, 16);
96 &mov( $tot, &DWP(&n2a($i*4),$P,"",0));
97
98 &movb( &LB($tmp1), &HB($R));
99 &movb( &LB($tmp2), &LB($R));
100
101 &rotr( $R, 16);
102 &xor( $L, $tot);
103
104 &mov( $tot, &DWP(&n2a($BF_OFF+0x0000),$P,$tmp1,4));
105 &mov( $tmp3, &DWP(&n2a($BF_OFF+0x0400),$P,$tmp2,4));
106
107 &movb( &LB($tmp1), &HB($R));
108 &movb( &LB($tmp2), &LB($R));
109
110 &add( $tot, $tmp3);
111 &mov( $tmp1, &DWP(&n2a($BF_OFF+0x0800),$P,$tmp1,4)); # delay
112
113 &xor( $tot, $tmp1);
114 &mov( $tmp3, &DWP(&n2a($BF_OFF+0x0C00),$P,$tmp2,4));
115
116 &add( $tot, $tmp3);
117 &xor( $tmp1, $tmp1);
118
119 &xor( $L, $tot);
120 # delay
121 }
122
123sub n2a
124 {
125 sprintf("%d",$_[0]);
126 }
127