Problem with function call

In the following code:
********************************************
#include <REG51.H>

unsigned char rem(unsigned char d1,unsigned char d2)
{

B=d2;
ACC=d1;
#pragma asm
DIV AB;
#pragma endasm
return B;
}

void main(void)
{
while(1)
{
unsigned char x,y,z;
P0=255;
x=65;
y=10;

z=rem(x,y);
P0=z;
}
}

*****************************************
I noticed that the instruction d1=ACC is not converted into assembly (Keil ignores this line).

Is this any reason behind that?..How can I solve the problem?

Thanks