I think that this is what you may be looking for. The generated assembly is simply the same as your assembly code. At least in the Raisonance compiler.
I assumed that you would want to access the variable as an integer otherwise the union could be removed.
/*
This simple routine assumes that you will be loading a variable wordvar with the two bytes from P0 and P1
and then accessing wordvar as an int.
The first step creates a structure consisting of two unsigned chars.
The second step creates a union of these two unsigned chars an a single unsigned int.
The code simply loads each byte with P0 or P1 to read the values simply read wordvar.x.
*/
#include <reg52.h>
#include <stdio.h>

struct Dual_Chars
{
unsigned char Hi_X;
unsigned char Lo_X;
};

union dual_access
{
unsigned int x;
struct Dual_Chars Test;
} wordvar;

void main (void)
{
while (1)
{
wordvar.Test.Lo_X = P0;
wordvar.Test.Hi_X = P1;
printf ("This is the contents of P0 and P1 %x.n",wordvar.x);
}
}

maziar navahan wrote:
-------------------------------
i require read two byte from P0,P1 and
write in one &quot;int var&quot; in C
in assembelly is very simple
mov Lowbyte,P0
mov HighByte,P1
in C how do it without get most time
note no use #programa Asm Directive !
i am require only &quot;c&quot; code

thank for help