+++ /dev/null
-The perl scripts in this directory are my 'hack' to generate
-multiple different assembler formats via the one origional script.
-
-The way to use this library is to start with adding the path to this directory
-and then include it.
-
-push(@INC,"perlasm","../../perlasm");
-require "x86asm.pl";
-
-The first thing we do is setup the file and type of assember
-
-&asm_init($ARGV[0],$0);
-
-The first argument is the 'type'. Currently
-'cpp', 'sol', 'a.out', 'elf' or 'win32'.
-Argument 2 is the file name.
-
-The reciprocal function is
-&asm_finish() which should be called at the end.
-
-There are 2 main 'packages'. x86ms.pl, which is the microsoft assembler,
-and x86unix.pl which is the unix (gas) version.
-
-Functions of interest are:
-&external_label("des_SPtrans"); declare and external variable
-&LB(reg); Low byte for a register
-&HB(reg); High byte for a register
-&BP(off,base,index,scale) Byte pointer addressing
-&DWP(off,base,index,scale) Word pointer addressing
-&stack_push(num) Basically a 'sub esp, num*4' with extra
-&stack_pop(num) inverse of stack_push
-&function_begin(name,extra) Start a function with pushing of
- edi, esi, ebx and ebp. extra is extra win32
- external info that may be required.
-&function_begin_B(name,extra) Same as norma function_begin but no pushing.
-&function_end(name) Call at end of function.
-&function_end_A(name) Standard pop and ret, for use inside functions
-&function_end_B(name) Call at end but with poping or 'ret'.
-&swtmp(num) Address on stack temp word.
-&wparam(num) Parameter number num, that was push
- in C convention. This all works over pushes
- and pops.
-&comment("hello there") Put in a comment.
-&label("loop") Refer to a label, normally a jmp target.
-&set_label("loop") Set a label at this point.
-&data_word(word) Put in a word of data.
-
-So how does this all hold together? Given
-
-int calc(int len, int *data)
- {
- int i,j=0;
-
- for (i=0; i<len; i++)
- {
- j+=other(data[i]);
- }
- }
-
-So a very simple version of this function could be coded as
-
- push(@INC,"perlasm","../../perlasm");
- require "x86asm.pl";
-
- &asm_init($ARGV[0],"cacl.pl");
-
- &external_label("other");
-
- $tmp1= "eax";
- $j= "edi";
- $data= "esi";
- $i= "ebp";
-
- &comment("a simple function");
- &function_begin("calc");
- &mov( $data, &wparam(1)); # data
- &xor( $j, $j);
- &xor( $i, $i);
-
- &set_label("loop");
- &cmp( $i, &wparam(0));
- &jge( &label("end"));
-
- &mov( $tmp1, &DWP(0,$data,$i,4));
- &push( $tmp1);
- &call( "other");
- &add( $j, "eax");
- &pop( $tmp1);
- &inc( $i);
- &jmp( &label("loop"));
-
- &set_label("end");
- &mov( "eax", $j);
-
- &function_end("calc");
-
- &asm_finish();
-
-The above example is very very unoptimised but gives an idea of how
-things work.
-
-There is also a cbc mode function generator in cbc.pl
-
-&cbc( $name,
- $encrypt_function_name,
- $decrypt_function_name,
- $true_if_byte_swap_needed,
- $parameter_number_for_iv,
- $parameter_number_for_encrypt_flag,
- $first_parameter_to_pass,
- $second_parameter_to_pass,
- $third_parameter_to_pass);
-
-So for example, given
-void BF_encrypt(BF_LONG *data,BF_KEY *key);
-void BF_decrypt(BF_LONG *data,BF_KEY *key);
-void BF_cbc_encrypt(unsigned char *in, unsigned char *out, long length,
- BF_KEY *ks, unsigned char *iv, int enc);
-
-&cbc("BF_cbc_encrypt","BF_encrypt","BF_encrypt",1,4,5,3,-1,-1);
-
-&cbc("des_ncbc_encrypt","des_encrypt","des_encrypt",0,4,5,3,5,-1);
-&cbc("des_ede3_cbc_encrypt","des_encrypt3","des_decrypt3",0,6,7,3,4,5);
-
projects / cassiopeia.git / blobdiff