Macros and advanced polly code teory, and code request

Is it possible to generated random numbers inside a macro? (at preprocessing time)
If not, could this feature be added?

I need it for generating polly code. Example:

Code:

org 100h

macro mov reg,num
{
if reg in <ax,bx> ; & rndnum=1
   mov cx,num
else if reg in <ax,bx> ;& rndnum=2
   mov dx,num
else if reg in <cx,dx>
   mov ax,num
end if
}

start:
mov ax,4
ret

If it had this feature, would be possible to add new IF's and based on number generated each time, change the registers building different executables at each compilation. This plus the already built-in feature load and store, people could make 100% polly+encrypted programs in very easy way. Good for program's security.
Also would be great to have macros to manipulate parts of instruction. Example:

MOV EAX, 5

and with some macros we could handle with each part:
MOV | EAX, | 5
and the macro would "know" the size of each part, and we could change these parts:
ADD EAX,5
MOV ECX,5
.
.
.

Is it possible?
Something like:
LoadOpcode buf, opc, opz_size
ChangeOpcode buf, OPCODE_ADD ;this would be a constant somewhere
opc:
MOV EBX,3
opc_size = $-opc
.
.
.
buf rb 10
So,

BEFORE:
MOV EBX,3

AFTER:
ADD EBX,3

Am I dreaming? Laughing

I hope it's possible to do!

rand_val = timestamp ;i forgot how to get it Smile

macro get_random { rand_val = rand_val ror 30 + 3*rand_val - 5*rand_val + 12312311313 ;etc } random if ... & (rand_val mod 3 = 1) else if ... & (rand_val mod 3 = 2) else ...