Andy Polyakov 313e6ec11f Add assembly support for 32-bit iOS. 9 年之前
..
arm-xlate.pl 313e6ec11f Add assembly support for 32-bit iOS. 9 年之前
cbc.pl f9c5e5d92e perlasm: fix symptom-less bugs, missing semicolons and 'my' declarations. 12 年之前
ppc-xlate.pl c7ada16d39 perlasm/ppc-xlate.pl update. 10 年之前
readme 478b50cf67 misspellings fixes by https://github.com/vlajos/misspell_fixer 11 年之前
sparcv9_modes.pl 775b669de3 Fix crash in SPARC T4 XTS. 9 年之前
x86_64-xlate.pl 902b30df19 perlasm/x86_64-xlate.pl: handle inter-bank movd. 10 年之前
x86asm.pl f642ebc1e2 Undo a90081576c94f9f54de1755188a00ccc1760549a 10 年之前
x86gas.pl ce876d8316 perlasm/x86gas.pl: limit special OPENSSL_ia32cap_P treatment to ELF. 10 年之前
x86masm.pl 2f8d82d641 perlasm/x86masm.pl: make it work. 9 年之前
x86nasm.pl c5cd28bd64 Extend OPENSSL_ia32cap_P with extra word to accomodate AVX2 capability. 12 年之前

readme

The perl scripts in this directory are my 'hack' to generate
multiple different assembler formats via the one original 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 {
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);