Common confusions
The growth of computing from the 1960s to today was rapid and chaotic. The chaos arose because the technology developed so rapidly that systems became obsolete in months, and that meant much of the design was obsolete but had been incorporated in systems that were now being held back by it. Similarly, many different notations and conventions arose – for example, does MOVE A,B move A to B, or B to A? Both conventions were used at the same time by different computers. Here are a few pointers to help with the confusion.
In this book, we will largely adopt the right-to-left convention for data movement. For example, add r1,r2,r2 indicates the addition of r2 and r3, and the sum is put in r1. As a means of highlighting this, I often put the destination operand of an operation in bold font.
Symbols are often used with different meanings. This is particularly true of #, @, and %.