Specifications

and is followed by index words and immediate operands for the source and

destination address fields as appropriate. Source address calculations are

performed before destination address calculations. Since each operand may

be anywhere in core storage or in the general registers, each memory location

is thus effectively provided with the arithmetic capabilities of an accumulator.

Further, since peripheral device registers and memory location are addressed

in the same way, the contents of peripheral data buffers can be stored or

loaded directly to and from memory without use of any general register. This

means that interrupt routines can be executed without saving and restoring

any of the general registers.