entry, then a
The above example illustrates a program consisting
of three segments. The second segment is loaded at
HSM location 11 00 1 O. The third segment will over lay
the first two segments at the location named SEG2.
The Equate (EQU) command assigns symbolic names
to values, or assigns the same address to two sym-
bolics. The statement,
enters the name XYZ in the symbol table, and to it,
assigns the value 6. One name may be equated to
another in similar fashion.
The above statement causes the Assembly to enter
the name BT AG in the table, and assign to it the
address previously assigned to ATAG. The symbol
appearing in the Operand field must have been pre-
viously defined. It must have appeared in the name
field of a prior statement.
BASE REGISTER CONTROLLING CODES
The USING Code indicates to the Assembler what
base address values will be in specific general re-
gisters at object time.
The Assembler creates a
table of these values, and then uses them to assign
registers and to compute displacements when base
references are not included in an expression. (See
The first operand denotes the value assumed to be in
The second operand specifies the regis-
The first operand may be a relocatable expression
while the second is simple and absolute.
The USING code does not load a general register. A
Load Multiple, Move Character or Branch and Link
instruction places the actual base address in a gen-
The assumed value of a register may be altered by
incorporating another USING statement at any place
in the source program.
The only function of the DROP code is to delete a
base value from the Assembly table.
It is not necessary to drop a base address from the
table prior to changing it with a second USING state-
EXTENDED MNEMONIC INSTRUCTIONS
The assembler provides a Simplified method of de-
fining the various options available via the Branch on
Condition instruction. The pseudo operation codes
listed below replace the BC and the associated mask.