Introduction

zlib is a collection of assembly language libraries for the TI-83 Plus series of programmable graphing calculators. The libraries are designed, but not required, to work with zproj (link: zproj).

Organization and Installation

The libraries reside in lib/spasm. The extra layer of indirection under lib accommodates the possibility of supporting additional assembler syntaxes in the future.

The organization of the libraries also cooperates with zproj, which is able to install files arranged in this way. In particular, if zproj is installed, running

zproj install lib

in the top-level directory of this repository will install the libraries for use with zproj.

Libraries

This distribution contains the following assembly language libraries:

• interrupt.asm -- This library facilitates the creation of custom interrupt routines which run at uniform time intervals.
• keyboard.asm -- This library provides routines that read user input from the keyboard.
• timer.asm -- This library implements an interrupt-based timer for use by applications.
• screen.asm -- This library implements an interface for staging and applying changes to the contents of the screen.
• draw.asm -- This library contains a collection of routines that use the screen.asm interface to draw simple geometric shapes on the screen.
• write.asm -- This library implements text-drawing routines using draw.asm and screen.asm.

These libraries depend on each other as follows:

• interrupt.asm
  • keyboard.asm
  • timer.asm
• screen.asm
  • draw.asm
    • write.asm

In this diagram, each library depends on all libraries above it in the hierarchy. For example, keyboard.asm and timer.asm both depend directly on interrupt.asm, while write.asm depends directly on draw.asm and indirectly on screen.asm.

Fonts

This distribution contains definitions of two monospaced fonts compatible with the write.asm library described above:

• fontFBF.asm
• fontSBF.asm

These two fonts differ primarily in glyph size: those of the first are Five-By-Five, while those of the second are Seven-By-Five, where the dimensions are of the form <pixels high> by <pixels wide>. Note, however, that the fonts are both technically six pixels wide, rather than five, to create a pixel-wide space between adjacent characters. This matters less than the height, which is currently implemented as advertised.

Supplementary Files

This distribution also contains two assembler source files which complement the above libraries:

• app.asm -- This file supports the structuring of TI-83 plus series calculator applications [1].
• ti83plus.inc -- This is a modified version of the standard assembler include file supplied by TI. [2]

Example

This distribution also includes an example Hello World application that uses zlib libraries. In order to both avoid a dependency on zproj and illustrate library usage, this application is written in pure spasm assembler syntax. In order to build the application, change directory into example and run make. This will generate three files:

• hello.lst -- the listing file generated by spasm,
• hello.hex -- the Intel HEX file generated by spasm, and
• hello.8xk -- the TI-83 Plus series application file generated by rabbitsign from hello.hex.

[1]	The term application used here refers to the specific TI-83 Plus series executable format of that name, not to executables in general.

[2]

The precise nature of this file's license is unclear, but it seems safe to distribute. I obtained the file from ti83plus.inc. Notably, it does not contain the license comment included in TI's original version, which demands not to be removed from any copies. I have not added this comment to the version I distribute because I have no way of knowing whether the file is actually a copy of TI's version. I do not claim authorship of this include file. If either TI or the author of the new version objects to its inclusion in this project, please contact me at [email protected].