PWM with 12F675

[fratello]

Hello everyone !
Since I bought a lot of 12F675, I think to try another schematic : lighting LED using software PWM. I wrote this code ; when power on the PIC, the LED give 20 % of light ; if buton is pressed, the LED lights 40%, then 60%, then 80% and, finally, 100 %. In my dreams ...because in practice that don't work like I wish. I know that code is not good...so, please, help me with some suggestion. Thanks in advance.