Assembler software for the Athena Computer



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The Athena Computer lacks essential software for general computational purposes. All programming on the Athena is performed using numeric machine instructions. Software was prepared to eliminate this problem. An assembler program was prepared to allow Athena users to program the Athena Computer in assembly language. The assembler program translates the user's assembly language program into numeric machine code for the Athena Computer. The assembler has features which allow the user ipo refer to storage locations using symbolic names and write operation codes in symbolic form. The assembler also allows the user to specify constants in the form which the user thinks of it, such as 1.0 for a floatingpoint constant. The assembler language programmer can write calls on closed subroutines and the assembler will generate the necessary linkages. Calls on open subroutines (macros) may be made. The assembler will automatically insert the macro code in-line following the macro call. To aid the user in debugging his program, numerous checks for errors are made and a error message is printed out if an error is detected. An Athena assembly language programmer's guide was prepared to aid users in programming the Athena. A systems programmer's guide was provided to aid in modifying the assembler program itself as requirements change.