Delta Radix

Try it online!

The Delta Radix is a desktop calculator designed specifically to be useful for binary and hexadecimal calculations.

Notable features:

• Mixed binary, hexadecimal, and decimal calculations
• Customisable bit width of arithmetic type (not limited to powers of 2!)
• Support for signed and unsigned data types
• Accurate simulation of overflow
• Mechanical keyswitches for input

Software

This repository is a Cargo workspace comprising a handful of crates. These are:

• delta-radix-os - The user-facing calculator software, 100% hardware-agnostic
• delta-radix-hal - Traits which the OS uses to interact with hardware (keypad, display, etc)
• delta-radix-hal-pico - Implementation of HAL traits for the Raspberry Pi Pico
• delta-radix-hal-sim - Implementation of HAL traits for a simulator which runs in the terminal
• delta-radix-hal-web - Implementation of HAL traits for a browser-based simulator with WebAssembly (build with wasm-pack build --target web, then visit index.html)
• flex-int - Arbitrary-precision arithmetic library used by the OS

The HAL implementations are the executable targets which should be flashed/run.

Elsewhere, you'll also find:

• delta-radix-numworks - Implementation of HAL traits for an app on the NumWorks graphing calculator.
  • This is a separate repository because it's not a pure-Cargo project, rather a Rust static library linked against a supporting C binary.

Hardware

hardware/ contains a KiCad schematic and PCB design.

cad/ contains a 3D-printable case which the PCB can be mounted into, and keycaps for the switches.

Usage

Note: Arithmetic parsing is incomplete! While they are implemented in the arithmetic library, there's no way to input operations other than addition yet.

Base specifiers can appear on either site of a number (xCAFE or CAFEx), whichever you prefer. A number without a base specifier is always interpreted as a decimal.

To change the result base, press the Format Select (->) key and then the base you'd like. Press the Format Select key twice to return to decimal.

To change the arithmetic data type, use the Menu key. Enter a number of bits, and use the +/- keys to choose signed or unsigned respectively.

Shift > Menu shows a menu of meta options, such as entering the bootloader.

Things left to do

• Faster parsing mode for constant overflow warnings
  • Parsing is slow, largely because of FlexInt::from_unsigned_decimal_string
  • Wouldn't be a problem for evaluation, but is annoying during editing (key-press lag)
  • Either add a faster overall parsing mode just for constant overflow warnings, or versions of number parsing which aren't suitable for evaluation but are fine for warnings (e.g. just use built-in Rust parsing, don't calculate overflow)
• "Clear" key (shift + del?)
• Variables
• Parentheses
• Scrolling expression input
• Show result as if unsigned
• Sleep after inactivity