https://github.com/tommythorn/sdcc-nascom

crt0 and Makefile to enable SDCC to produce code for Nascom 2
https://github.com/tommythorn/sdcc-nascom

Last synced: about 5 hours ago
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crt0 and Makefile to enable SDCC to produce code for Nascom 2

• Host: GitHub
• URL: https://github.com/tommythorn/sdcc-nascom
• Owner: tommythorn
• Created: 2014-11-25T07:33:21.000Z (about 10 years ago)
• Default Branch: master
• Last Pushed: 2014-12-31T08:54:35.000Z (about 10 years ago)
• Last Synced: 2025-01-11T16:16:18.745Z (5 days ago)
• Language: C
• Size: 137 KB
• Stars: 0
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# SDCC 3.4.0 support for NASCOM 2 running NASSYS-3 (and 1?)

Includes a crt0_nascom.s which provides the essential support for NASCOM 2.

## Features

* `putchar()` and `getchar()` (and thus all derived IO like `printf()` etc.) use the NASSYS IO.

Note, `putchar()` translates `0x23` to `0x9E` so that `'#'` prints as expected rather than the British pound symbol `'£'`.

* `exit()` returns control to NASSYS 3 as recommended.

## Demos

* nasmacs - a small, simple, but powerful editor (EMACS inspired)

## Issues

* SDCC 3.4.0 doesn't add float support for `printf()` by default (otherwise floats are mostly supported).

* Why can't the linker figure out to place the data at the end of the text rather than having to give it explicitly?

For a kludgy workaround: http://sourceforge.net/p/sdcc/feature-requests/399/

* Similarily, but less important: my hack to put init at `0x1000` and `code-loc 0x1004` isn't very elegant.  Surely one could do better?

* Stack pointer is hardwired to start at `0xE000` (the end of ROM Basic); might be better if it could automatically find the end of RAM or otherwise be configurable.