Then we would need to look only at bit 0 in p0 and bit 0 in p1. This further complicates the problem. In assembly we can assign a name to a bit and refer to it by that name, instead of a bit in a port. This is done with an equate directive . Directives are assembler commands that don't result in program but instead direct the assembler to some action.
All directives start with a period.
In the DS5000 there are many bit locations. 128 of them were discussed in the previous lesson. There are others like all the bits in the accumulator, all the bits in the p0, p1, p2, and p3 ports. Each one is assigned an address by the DS5000 and can't be changed. The first 128 are the 16 bytes of internal ram following the first 32 bytes.