1#!/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
128