I won't write the code for you but I will help you to write it yourself.
Before looking at instructions you need to understand how sleep mode and interrupts work. I will try to explain:
Sleep mode in that device is just a switch that disconnects the clock from the processing circuitry. When the switch is 'on' everything woks as normal, when you use the SLEEP instruction the switch turns off and the processor goes into suspended animation, it just freezes and ceases to run any further code. Note that because SLEEP is itself an instruction, it will switch the clock off at the end of executing it and not before, this means it can cleanly resume at a later time. As all internal operations are synchronized to the clock, everything except Timer 1 will freeze, including the state of the pins and being a MOS device, the current consumption will also drop to almost zero. It will suspend with the pins in their current input or output state and with any current flowing through the pins still there, in other words it won't disconnect from the outside World when it sleeps so you have to be careful to take into account that pins may still source or sink.
Interrupts are one of the most useful features on any microcontroller and the 12F683 is no exception. When you write a program you think of it as having 'flow', the path the instructions will follow as you pass through it or enter loops or subroutines. Interrupts work differently because in most cases they are triggered by an event outside of the program flow. For example you could have a program with a long delay loop in it that also has to react to a change on one of the pins, it wouldn't be able to do both because it wouldn't be able to read the pin until the delay routine finished. Interrupts do exactly as their name suggests, they break the normal flow and grab the attention of the processor regardless of what code it is executing at the time. It follows that interrupts are reliant on circuits in the controller rather than software instructions to trigger them. In that example, a signal on the pin could 'interrupt' the delay loop, do something important then when finished it could tell the delay loop to resume.
Interrupts can come from several sources, look at section 12.4 on the data sheet where they are all listed. The GP2/INT source allows a pin to be used to directly trigger an interrupt, GPIO change allows any input pins changing state to trigger an interrupt and the others come from the peripherals built into the silicon.
The one you should be interested in is the "Timer 1 overflow interrupt". Timer 1 always counts upwards, when it reaches maximum value (all 1's in the timer registers) the next count will make it roll over back to all zeroes and at the same time trigger the overflow interrupt. Consider that Timer 1 is a hardware counter and it keeps on running independently of the software so unless the program reads its value, it has no knowledge of what it holds at any time. When that roll over happens, and if you have enabled the TMR1IE bit and GIE bits in the INTCON register, an interrupt will be triggered and only then will the code in the ISR routine be called.
On that device there is only one ISR vector, so all the sources of interrupts cause the same ISR code to be called. Several of the interrupt enable bits can be set at the same time, for example, as well as Timer1 overflow you could have the ADC interrupt enabled, that's is why there is a line in the ISR to check which of the sources was the cause. For Timer1 the TMR1IF bit will be set. If there are several sources, you have to check each bit and branch to the appropriate code to deal with it. Note that you should reset the interrupt bit in your code but never change the GIE bit because that could effect the operation of other interrupt sources. The 'golden rule' with ISRs is get out of them as quickly as possible, especially if you have enabled multiple sources because other triggers might be missed before the routine finishes.
So what you need to do is remove the lines
Code:
if (counter1==100){
LED1 =~LED1;
LED2 =~LED2;
counter1=1;
}
and put them in the main() loop somewhere, then set the bits in the INTCON register to enable Timer1 overflow interrupts.
There are other issues with your code but see if you can put that fix in first then I'll explain the other problems.
Brian.