Hi.

I need some help testing a bit in an 8-bit register. For example, how would I go about reading bit 4 of that specific register? I've looked at 'test' but I'm not really sure how to go to a specific position in the register and test the bit. How would I do this?

Thank you,

- Steve

test reg, 2^bit

so, to test bit 4, you'd calculate 2^4 (two raised to the power of four). That's 16. Then, "test reg, 16". Now you can do something like "sete al" to set AL to the bitvalue.

There's also the "BT" (bit test) instruction - check out an x86 reference for more information.

Thanks, f0dder. Very helpful as always.