Table of Contents
Advertisement
32
The Processor and the Operating System
Machine Instructions
The machine instruction set underlying the assembly language system consists of 92 instruc-
tions, divided into eleven groups. The groups are -
Load/Store
Integer Math
Branch
Test/Branch
Test/ Alter /Branch
Shift-Rotate
Logical
Stack
BCD Math
I/O
Miscellaneous
Operands
Operations placing values into registers or memory.
Operations involving integer arithmetic.
Operations altering the execution sequence unconditionally.
Operations altering the execution sequence, dependent upon
some condition.
Operations altering the execution sequence and a value, de-
pendent upon some condition.
Operations performing re-arrangments of the bits in the A or
B register.
Operations performing logical functions on the A or B regis-
ters.
Operations managing stacks.
Operations involving BCD arithmetic.
Operations specifically involving I/O operations.
Some unclassifiable operations.
Most instructions require operands. These operands have general forms which they may assume.
Many instructions contain an operand which is the address on which the function is to be
performed. This {location} may be a constant (octal or decimal) or it may be a symbol. It also
may be an expression containing any allowable combination of constants and symbols. For a
full discussion of allowable expressions and symbols, and the "types" they are allowed to
assume, consult "Symbolic Operations" in Chapter 4.
Advertisement
Table of Contents
