Calc-U-59
Calc-U-59 Calculator Emulation
Free
Calc-U-59 is a research tool for classic calculators TI-59, TI-58, and TI-58C — built for anyone who wants to understand these machines, not just use them. Step through ROM code, inspect internal registers, trace printer output, and explore the architecture of one of the most capable handheld computers of the late 1970s.
CYCLE-ACCURATE EMULATION
The TMC0501 processor is emulated at the cycle level, reproducing the exact behaviour of the original hardware — including the TI-58C's constant memory, preserved across restarts. The Master Library ROM is included.
INTEGRATED DEBUGGER
Inspect program memory, data registers, CPU state, and internal SCOM registers live as the machine runs. Step through instructions one at a time, or let the emulator run and freeze it at any point. You can even run your own assembly programs! Available on iPad (landscape) and Mac.
PAPER TAPE PRINTER
A functional recreation of the PC-100C thermal printer with dot-matrix font rendering. Trace exactly what programs print and why. Copy output as plain text or as a high-resolution bitmap.
MAGNETIC CARD READER
Load and save programs and data registers as card files, stored on your device and synced via iCloud. Bring old listings back to life and run them under the debugger.
STATE FILES
Load .ti59 and .ti58(c) state files to instantly configure the machine with a program, registers, and flags — ideal for sharing reproducible scenarios or revisiting known machine states.
SOLID STATE MODULES
Select a Solid State Module and run programs from there.
Whether you are reconstructing programs from memory, tracing ROM internals, or studying how AOS operator precedence actually works at the instruction level, Calc-U-59 gives you the tools to go deep.
Ratings & Reviews
• PRINTER: Dot-matrix output now correctly supports printer-interrupt, also known as "High Rez Graphics". This is a hack documented in the 1982 magazine "PPX Exchange". Check the GitHub repository for the example state file "texas-print.ti59".
FIXES
• PRINTER: Multiple blank-line errors fixed (ADV button). Blank lines now match the real PC-100A/B/C exactly.
• DEBUG LOG: Fixed out-of-memory crash and GUI slowdown when the LOG panel is active at DEBUG level.
The developer, Martin Erzberger, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Martin Erzberger
- Size
- 4 MB
- Category
- Productivity
- Compatibility
Requires iOS 18.0 or later.
- iPhone
Requires iOS 18.0 or later. - iPad
Requires iPadOS 18.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Martin Erzberger