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author | cvs2svn <admin@example.com> | 2008-07-28 23:44:11 +0000 |
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committer | cvs2svn <admin@example.com> | 2008-07-28 23:44:11 +0000 |
commit | 466614843d3969042821d3844ede52cbbbef414e (patch) | |
tree | dd1b8dd6247047a42f65a4669d862134a8e90160 /src/lib/libcrypto/perlasm/readme | |
parent | 10837c3c47f1b9d7d1a061fff2327a4e280ba338 (diff) | |
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This commit was manufactured by cvs2git to create tag 'OPENBSD_4_4_BASE'.OPENBSD_4_4_BASE
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-rw-r--r-- | src/lib/libcrypto/perlasm/readme | 124 |
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diff --git a/src/lib/libcrypto/perlasm/readme b/src/lib/libcrypto/perlasm/readme deleted file mode 100644 index f02bbee75a..0000000000 --- a/src/lib/libcrypto/perlasm/readme +++ /dev/null | |||
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1 | The perl scripts in this directory are my 'hack' to generate | ||
2 | multiple different assembler formats via the one origional script. | ||
3 | |||
4 | The way to use this library is to start with adding the path to this directory | ||
5 | and then include it. | ||
6 | |||
7 | push(@INC,"perlasm","../../perlasm"); | ||
8 | require "x86asm.pl"; | ||
9 | |||
10 | The first thing we do is setup the file and type of assember | ||
11 | |||
12 | &asm_init($ARGV[0],$0); | ||
13 | |||
14 | The first argument is the 'type'. Currently | ||
15 | 'cpp', 'sol', 'a.out', 'elf' or 'win32'. | ||
16 | Argument 2 is the file name. | ||
17 | |||
18 | The reciprocal function is | ||
19 | &asm_finish() which should be called at the end. | ||
20 | |||
21 | There are 2 main 'packages'. x86ms.pl, which is the microsoft assembler, | ||
22 | and x86unix.pl which is the unix (gas) version. | ||
23 | |||
24 | Functions of interest are: | ||
25 | &external_label("des_SPtrans"); declare and external variable | ||
26 | &LB(reg); Low byte for a register | ||
27 | &HB(reg); High byte for a register | ||
28 | &BP(off,base,index,scale) Byte pointer addressing | ||
29 | &DWP(off,base,index,scale) Word pointer addressing | ||
30 | &stack_push(num) Basically a 'sub esp, num*4' with extra | ||
31 | &stack_pop(num) inverse of stack_push | ||
32 | &function_begin(name,extra) Start a function with pushing of | ||
33 | edi, esi, ebx and ebp. extra is extra win32 | ||
34 | external info that may be required. | ||
35 | &function_begin_B(name,extra) Same as norma function_begin but no pushing. | ||
36 | &function_end(name) Call at end of function. | ||
37 | &function_end_A(name) Standard pop and ret, for use inside functions | ||
38 | &function_end_B(name) Call at end but with poping or 'ret'. | ||
39 | &swtmp(num) Address on stack temp word. | ||
40 | &wparam(num) Parameter number num, that was push | ||
41 | in C convention. This all works over pushes | ||
42 | and pops. | ||
43 | &comment("hello there") Put in a comment. | ||
44 | &label("loop") Refer to a label, normally a jmp target. | ||
45 | &set_label("loop") Set a label at this point. | ||
46 | &data_word(word) Put in a word of data. | ||
47 | |||
48 | So how does this all hold together? Given | ||
49 | |||
50 | int calc(int len, int *data) | ||
51 | { | ||
52 | int i,j=0; | ||
53 | |||
54 | for (i=0; i<len; i++) | ||
55 | { | ||
56 | j+=other(data[i]); | ||
57 | } | ||
58 | } | ||
59 | |||
60 | So a very simple version of this function could be coded as | ||
61 | |||
62 | push(@INC,"perlasm","../../perlasm"); | ||
63 | require "x86asm.pl"; | ||
64 | |||
65 | &asm_init($ARGV[0],"cacl.pl"); | ||
66 | |||
67 | &external_label("other"); | ||
68 | |||
69 | $tmp1= "eax"; | ||
70 | $j= "edi"; | ||
71 | $data= "esi"; | ||
72 | $i= "ebp"; | ||
73 | |||
74 | &comment("a simple function"); | ||
75 | &function_begin("calc"); | ||
76 | &mov( $data, &wparam(1)); # data | ||
77 | &xor( $j, $j); | ||
78 | &xor( $i, $i); | ||
79 | |||
80 | &set_label("loop"); | ||
81 | &cmp( $i, &wparam(0)); | ||
82 | &jge( &label("end")); | ||
83 | |||
84 | &mov( $tmp1, &DWP(0,$data,$i,4)); | ||
85 | &push( $tmp1); | ||
86 | &call( "other"); | ||
87 | &add( $j, "eax"); | ||
88 | &pop( $tmp1); | ||
89 | &inc( $i); | ||
90 | &jmp( &label("loop")); | ||
91 | |||
92 | &set_label("end"); | ||
93 | &mov( "eax", $j); | ||
94 | |||
95 | &function_end("calc"); | ||
96 | |||
97 | &asm_finish(); | ||
98 | |||
99 | The above example is very very unoptimised but gives an idea of how | ||
100 | things work. | ||
101 | |||
102 | There is also a cbc mode function generator in cbc.pl | ||
103 | |||
104 | &cbc( $name, | ||
105 | $encrypt_function_name, | ||
106 | $decrypt_function_name, | ||
107 | $true_if_byte_swap_needed, | ||
108 | $parameter_number_for_iv, | ||
109 | $parameter_number_for_encrypt_flag, | ||
110 | $first_parameter_to_pass, | ||
111 | $second_parameter_to_pass, | ||
112 | $third_parameter_to_pass); | ||
113 | |||
114 | So for example, given | ||
115 | void BF_encrypt(BF_LONG *data,BF_KEY *key); | ||
116 | void BF_decrypt(BF_LONG *data,BF_KEY *key); | ||
117 | void BF_cbc_encrypt(unsigned char *in, unsigned char *out, long length, | ||
118 | BF_KEY *ks, unsigned char *iv, int enc); | ||
119 | |||
120 | &cbc("BF_cbc_encrypt","BF_encrypt","BF_encrypt",1,4,5,3,-1,-1); | ||
121 | |||
122 | &cbc("des_ncbc_encrypt","des_encrypt","des_encrypt",0,4,5,3,5,-1); | ||
123 | &cbc("des_ede3_cbc_encrypt","des_encrypt3","des_decrypt3",0,6,7,3,4,5); | ||
124 | |||