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A toolkit for the Haverford Educational RISC Architecture (HERA) assembly language, comprising an interpreter, a debugger, an assembler, and a disassembler.


You can install hera-py with pip:

$ pip3 install hera-py


After installation, use the hera command to run a HERA program:

$ hera main.hera

Enter the interactive debugger with the debug subcommand:

$ hera debug main.hera

Assemble a HERA program into machine code:

$ hera assemble main.hera

Disassemble machine code back into the human-readable HERA syntax:

$ hera disassemble main.hera.lcode

You can also preprocess a HERA program without running it, to see how pseudo-instructions and labels are resolved to HERA code:

$ hera preprocess main.hera

Comparison with HERA-C and Hassem

HERA-C is the current HERA interpreter used at Haverford. It is implemented as a shell-script wrapper around a set of C++ macros that expand HERA instructions into C++ code, which is then compiled by g++.

hera-py improves on HERA-C in the following areas:

  • Includes a purpose-built HERA debugger
  • Concise and accurate error messages
  • Ease of use
    • Cross-platform and easy to install
    • Configurable with command-line options
    • Does not create temporary files
    • Command name has six fewer letters than HERA-C-Run

hera-py also supports several features that HERA-C does not:

  • Setting registers to the value of a label
  • Detecting stack overflow
  • Multi-precision multiplication
  • Relative branching by a fixed integer value (e.g., BRR(10))
  • Branching by the value of a register (e.g., SET(R1, 20); BR(R1))
  • Detecting invalid relative branches

HERA-C has a few features that hera-py does not:

  • C-style #define macros (and more generally the ability to embed arbitrary C++ code in HERA programs)

Small to medium-sized programs generally run faster with hera-py than with HERA-C, while very large programs are typically faster with HERA-C.

Hassem is the current HERA assembler used at Haverford. hera-py has better error messages than Hassem, allows the user greater control of output (e.g., with the --stdout flag), and fixes some Hassem bugs.


Thank you to Christopher Villalta for valuable feedback on early iterations of this project.


Toolkit for the Haverford Educational RISC Architecture (HERA) assembly language








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