2008 Omni Drive Code Help

[Vasily Zaitsev]

Our robot is using a four wheel, four motor omni drive system. Our code gives good output except for sometimes it swaps outputs. Instead of giving a 250, it gives a 4.

drive_ly and drive_lx are our drive joystick.
motor_fl_1 and all the others are the variables we send to the motors. fl=front left.
pwm_drive_fl are the actual motors.

Heres the code:

  if ( (drive_ly + drive_lx - 127) > 254 )
    motor_fl_1 = 254;
  else if ( ( drive_ly + drive_lx - 127) < 0 )
    motor_fl_1 = 0;
  else motor_fl_1 = drive_ly + drive_lx - 127;

  if ( ( 127 - drive_ly + drive_lx ) > 254 )
    motor_fr_1 = 254;
  else if ( (  127 - drive_ly + drive_lx ) < 0 )
    motor_fr_1 = 0;
  else motor_fr_1 =  127 - drive_ly + drive_lx;

  if ( ( 382 - drive_ly - drive_lx ) > 254 )
    motor_br_1 = 254;
  else if ( (  382 - drive_ly - drive_lx ) < 0 )
    motor_br_1 = 0;
  else motor_br_1 =  382 - drive_ly - drive_lx;

  if ( ( 127 + drive_ly - drive_lx ) > 254 )
    motor_bl_1 = 254;
  else if ( (  127 + drive_ly - drive_lx ) < 0 )
    motor_bl_1 = 0;
  else motor_bl_1 =  127 + drive_ly - drive_lx;



  if ( (motor_fl_1 < 137) && ( motor_fl_1 > 117 ) )
    pwm_drive_fl = 127;
  else  pwm_drive_fl = motor_fl_1;

  if ( (motor_fr_1 < 137) && ( motor_fr_1 > 117 ) )
    pwm_drive_fr = 127;
  else  pwm_drive_fr = motor_fr_1;

  if ( (motor_br_1 < 137) && ( motor_br_1 > 117 ) )
    pwm_drive_br = 127;
  else  pwm_drive_br = motor_br_1;

  if ( (motor_bl_1 < 137) && ( motor_bl_1 > 117 ) )
    pwm_drive_bl = 127;
  else  pwm_drive_bl = motor_bl_1;

we're pretty sure its an overflow error, but this code should make up for that.

can anybody help please?