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THE GENERAL ASSEMBLY PROGRAM
General Description
The General Assembly Program is an effort-saving procedure that permits writing programs
in specific mnemonics rather than in the absolute computer coding. For example, mnemonic
ADO is used to indicate the add 1 operation, mnemonic SBO to indicate the subtract 1 operation,
etc. The instruction mnemonics are chosen to be as self-explanatory as possible.
The General Assembly Program examines the mnemonics and translates them into the corre-
sponding absolute c9de of the computer.
The output of the assembly program is the original
source program converted to absolute code in machine readable form on punched cards, magnetic
tape, or paper tape.
When a program is written, memory addresses may be specified in decimal or symbolic notation.
ADO 100 means add 1 to location 100. ADO BETA means add 1 to location BETA, where the
General Assembly Program automatically assigns the memory location of BETA. The pro-
grammer need only specify the starting address into ·Which the first instruction of the program
is stored.
In addition to the mnemonic code for the instructions in the normal list of instructions, the
General Assembly Program uses other mnemonic codes called "pseudo-operations." A pseudo-
operation is not a computer instruction but is a control instruction to the General Assembly
Program.
The pseudo-operation has the same form as a computer instruction, and it is listed
like a normal instruction in the preparation of a program. For example, ORG is a pseudo-
operation which may be used to indicate the starting address in the assignment of a program
to memory. Thus, ORG 400 indicates thataprogram is to enter memory with the first instruction
at location 400 decimal.
The General Assembly Program automatically assigns succeeding
memory locations to the remaining instructions of the program.
In addition to translating the mnemonics into machine language, the General Assembly Program
provides the following advantages:
1.
Various errors, specifically clerical errors, are detected during program assembly.
This effects a substantial saving in program debugging effort, because the errors can
be rectified prior to debugging.
2.
The assembler generates punched cards and/ or a listing on the high-speed printer that
includes all error indications, the assembled program, and a complete list of symbols
used, with their assigned memory locations.
This provides an accurate record of the
program plus helpful auxiliary information.
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