On
graphing calculator
A graphing calculator (also graphics calculator or graphic display calculator) is a handheld computer that is capable of plotting graphs, solving simultaneous equations, and performing other tasks with variables. Most popular graphing calculat ...
s, an assembly
shell is a program that is used to run other programs written in the calculator's native
machine code rather than the calculator's standard
high-level programming language
In computer science, a high-level programming language is a programming language with strong Abstraction (computer science), abstraction from the details of the computer. In contrast to low-level programming languages, it may use natural language ...
. While all assembly shells can run assembly programs, some can also run high-level programs. For example, MirageOS and DoorsCS, two popular TI-83+ assembly shells, can run
TI-BASIC programs by placing a colon as the first bit of code on the first line in the program.
Assembly shells were created when calculator manufacturers did not support native-code programming. ZShell,
The ticalc.org TI-85 page includes information on the history and use of ZShell and later, similar software.
/ref> the first assembly shell, was created for the TI-85 after an exploit was found using a hacked memory backup file containing the shell to bypass the calculator's standard operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
. Rather than crack down on users who had managed to bypass the OS to run their own code, Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
chose to release native programming information for its then-upcoming TI-83 calculator. However, their stance changed and they decided to remove native code functionality from the TI-84 plus CE, making an assembly shell necessary once again.
Although this rendered the traditional assembly shell unnecessary on the TI-83 hardware, calculator programmers continued to develop shells to supplement or replace the standard operating system. Since the TI-83, TI has supported assembly-level programming on all subsequent graphing calculators, though similar shell hacks needed to be created for older hardware, such as the TI-82 and the TI-92.
Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...
also supports assembly language programming, though onboard programming tools mean that a separate shell is not needed.
See also
* TI-BASIC
* Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall ...
* Hewlett-Packard
The Hewlett-Packard Company, commonly shortened to Hewlett-Packard ( ) or HP, was an American multinational information technology company headquartered in Palo Alto, California. HP developed and provided a wide variety of hardware components ...
References
External links
ticalc.org
- An archive of Assembly and Basic programs for TI calculators.
Graphing calculator software
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