dec	_mainoff  //(0x50)
	mov	a,#0xff   
	cjne	a,_mainoff,00124$ //Skips
	dec	(_mainoff + 1)  
00124$:
	mov	a,_mainoff //(0x4F)
	cpl	a  
	mov	_mainoff,a //(0xB0)
	mov	a,(_mainoff + 1) //(0xC3)
	cpl	a
	mov	(_mainoff + 1),a //(0x3C)