Programming for Microprocessors

Assembly

language

33

The symbols with constant meaning are reserved, and may not be used

for other purposes.

Names

In programming it is extremely convenient to refer to quantities with-

out knowing their exact value. When a mathematician plans a calcula-

tion, he will do so in terms of symbolic quantities like χ οι y. The sym-

bols are replaced by actual numbers at the latest possible moment, just

before the calculation is actually made; this adds to the generality and

flexibility of the planning process. In the same way, the constants and

addresses in a program are often referred to by names, which are only

replaced by their actual values whe ...