https://github.com/iafisher/hera-py

Toolkit for the Haverford Educational RISC Architecture (HERA) assembly language
https://github.com/iafisher/hera-py

assembler assembly-language haverford interpreter

Last synced: 25 days ago
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Toolkit for the Haverford Educational RISC Architecture (HERA) assembly language

• Host: GitHub
• URL: https://github.com/iafisher/hera-py
• Owner: iafisher
• License: mit
• Created: 2018-11-05T02:56:33.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2021-09-30T23:35:41.000Z (about 3 years ago)
• Last Synced: 2024-09-30T06:06:44.931Z (about 1 month ago)
• Topics: assembler, assembly-language, haverford, interpreter
• Language: Python
• Homepage: https://iafisher.com/projects/hera
• Size: 896 KB
• Stars: 6
• Watchers: 2
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: CHANGELOG.md
  • License: LICENSE

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README

        
# hera-py

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A toolkit for the [Haverford Educational RISC Architecture](http://cs.haverford.edu/resources/hera) (HERA) assembly language, comprising an interpreter, a debugger, an assembler, and a disassembler.

## Installation

You can install hera-py with pip:

```

$ pip3 install hera-py

```

## Usage

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.

## Acknowledgements

Thank you to [Christopher Villalta](https://github.com/csvillalta) for valuable feedback on early iterations of this project.