Bipolar Stepper Motor

I am using 293d for bipolar stepper motor drive and it is not working why I don't know... the coding I used is..

#include<htc.h>

int _XTAL_FREQ=12000000;


int i;
void forv();
void rev();
void reva();
void fora();

void DelayMs(unsigned char delay)
{
unsigned int j;
for(i=0;i<=delay;i++)
{
for(j=0;j<=1000;j++);
}
}

void port_initialize()
{
TRISB=0X00;
PORTB=0x00;
TRISC=0xFF;

#define a RC0
#define b RC1
#define c RC2
#define d RC3


}

void main()

{
port_initialize();
while(1)
{
 if(a>
0x00)
 { 
  forv();
 }
 if(b>
0x00)
 {
  rev();
 }
 if(c>
0x00)
 {
  reva();
 }
 if(d>
0x00)
 {
  fora();
 }
}
}

void forv()
{
PORTB=0x08;
DelayMs(50);
PORTB=0x02;
DelayMs(50);
PORTB=0x04;
DelayMs(50);
PORTB=0x01;
DelayMs(50);
}

void rev()
{

PORTB=0x08;
DelayMs(100);
PORTB=0x09;
DelayMs(100);
PORTB=0x01;
DelayMs(100);
PORTB=0x03;
DelayMs(100);
PORTB=0x02;
DelayMs(100);
PORTB=0x06;
DelayMs(100);
PORTB=0x04;
DelayMs(100);
PORTB=0x0C;
DelayMs(100);
}
void reva()
{
PORTB=0x06;
DelayMs(150);
PORTB=0x0C;
DelayMs(150);
PORTB=0x09;
DelayMs(150);
PORTB=0x03;
DelayMs(150);
}
void fora()
{
PORTB=0x06;
DelayMs(300);
PORTB=0x0C;
DelayMs(300);
PORTB=0x09;
DelayMs(300);
PORTB=0x03;
DelayMs(300);
}

And this is the diagram i used... i dont know what is the reason behind the problem... but it is not rotating... but i hear the sound in the motor... supply i used is 12V battery with 7812 regulator and for Microcontroller 9V battery...
i am first trying to rotate in forward direction for that i used different delay and made this... my motor winding are Yellow Orange Brown and Black among which Yellow and Orange are one winding and Black and Brown are another winding.. pls help me...

@kanniyappan
which compiler u r using?is yr code working on protius?

Make sure you have used right kind of stepper motor. Are you using a bipolar stepper?

supply i used is 12V battery with 7812 regulator and for Microcontroller 9V battery...

are you using a regulator ahead of 9v battery? max vdd as in datasheet for 16f887 is +7.5 v. 5 volts is recommended.
also mention if your simulation on proteus is working. if it is working, we will focus on the hardware.

@ kanniyappan
there is no need of 7812 for steeper motor as it also limit the current
another possibility can be a current of motor if it is a big motor then use L298 instead of L293
in your coding there is no setting of configurations words
in Proteus no need of configuration but in real you need it
also try to swap the pair of wires of motor windings

Sorry for late reply, i made it working but don't know what happen, it is working now. but how to get the high holding torque form the motor.