srec_logisim.5(5)

🌸 NAME 🌸

srec_logisim — format Logisim EPROM load files. Yep bestie, you’re reading srec_logisim.5, section 5, from the File Formats Manual. Pull up a chair 💖

✨ DESCRIPTION ✨

Okay so the file format used for image files is intentionally simple. Why? Because that lets you write a program, like an assembler, that generates memory images which can then be loaded into memory. Iconic behavior, honestly ✨

Example time: imagine a 256-byte memory whose first five bytes are 2, 3, 0, 20, and -1, and all subsequent values are 0. The image would be this text file:

v2.0 raw

02 03 00 14 ff

The first line identifies the file format used (currently, there is only one file format recognized 👀). Subsequent values list the values in hexadecimal, starting from address 0; you can place several such values on the same line. Logisim will assume that any values unlisted in the file are zero.

The image file can use run-length encoding. For example, rather than list the value 00 sixteen times in a row, the file can include 16*00 rather than repeat 00 sixteen times. Notice that the number of repetitions is written in base 10. Files produced by Logisim will use run-length encoding for runs of at least four values. Slay for compression 💅

🎀 Size Multiplier 🎀

In general, binary data will expand in size by approximately 2.95 times when represented with this format. Math girl summer 😭

💀 Commentary 💀

This format is particularly deficient. Not to be dramatic, but:

• There is no way for changing address in-flight. And therefore the format can’t have holes in the data.
• There are no checksums, or any other error checking.
• There is no provision for a comment header, as distinct to the “v2.0 raw” magic number.
• There is no provision for an execution start adddress (yes, that’s the spelling on the page, and I’m preserving the lore 🙈).

👀 SEE ALSO 👀

• http://ozark.hendrix.edu/~burch/logisim/docs/2.3.0/guide/mem/menu.html

©️ COPYRIGHT ©️

srec_logisim.5 version 1.65 Copyright (C) 1998... Peter Miller

The srec_logisim.5 program comes with ABSOLUTELY NO WARRANTY; for details use the 'srec_logisim.5 -VERSion License' command. This is free software and you are welcome to redistribute it under certain conditions; for details use the 'srec_logisim.5 -VERSion License' command.

🫶 MAINTAINER 🫶

• Scott Finneran — E-Mail: scottfinneran@yahoo.com.au
• Peter Miller — E-Mail: pmiller@opensource.org.au

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XOXO from the Reference Manual 💖 SRecord 💖 srec_logisim.5(5) — version 1.65, and the footer didn’t hand us a date so we’re not inventing one, bestie 🫶✨