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REMARKS FIELD
Columns 25- 75 make up the remarks field.
Remarks are written in this field for reference
by the programmer.
These remarks are punched in the assembly program source deck, but the
information is not carried through to the final object program. Thus, information in the remarks
field is obtained only on a printed listing.
SEQUENCE FIE.LD
Columns 76 - 80 constitute the sequence field.
Each card is numbered so that a deck can be
sorted into proper order· should the cards get out of sequence. The sequence field is not pertinent
to the General Assembly Program.
Relative Addressing
The General Assembly Program provides facility for the assignment of addresses relative to
some starting point (relative addressing).
Assume, for example, that the symbol B is equal to
memory location 0500.
Using the technique of relative addressing, memory location 0510 can
now be addressed by simply writing B+lO in the operand field of the coding sheet:
Symbol
B
Operation
EQU
LDA
LDA
Operand
500
B
B+lO
The EQU pseudo-operation equates the symbol B to memory location 0500. The instruction
LDA (Load Register A) loads the A-register with the contents of memory location 0500. The
next LDA instruction, some program steps later, loads register
A
with the contents of B+lO
(location 0500 + 10
=
0510).
Pseudo-Operations
In addition to the machine instructions in the DA TANET-30 instruction repertoire, there are a
number of pseudo-operations which facilitate programming.
A
pseudo-operation is not a computer
instruction.
It
is a control instruction to the General Assembly Program in assembling a pro-
gram, and it is listed the same as a normal instruction in the preparation of a program. Normally,
pseudo-operations are never executed by the computer as actual instructions. Pseudo-operations
are used to generate constants, to control the assembly process, or to annotate the program
listing.
[ID&\lT&~~lTCJ ~@------------
V-65
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