I'm using an ATTiny84 and I have both a switch and a pin header attached to the MOSI pin. I am reading the value of the switch in my program, and I'm using the pin header (along with headers to MISO, RESET, and SCK) to program the chip with my Arduino. I won't be pressing the switch while programming the chip.

When I start programming the chip, will the code already on my ATTiny restart execution, or will it wait until RESET is no longer held low? All I could find in the datasheet is that the pins "are tri-stated when a reset condition becomes active" which I don't understand.