Some years ago I started to define words for arithmetics on arbitrary number strings (ascii). I terrorized people at various sites with my questions and solutions and got a lot of feedback. Then I changed from ascii strings with most significant numbers in lowmem to "cellimal" system with least significant cells in lowmem. By now, it is a rather fast and general system working in Forth style, with a stack for arithmetics and a second stack for storing data. Almost all the words are very similar to the words for other kind of calculations in Forth. Tested on:
32 bit SP-Forth with Vista and Windows 10
32 bit GForth with Vista, Windows 10 and Android
32 bit SwiftForth with Vista and Windows 10
Win32Forth with Vista and Windows 10
64 bit GForth and GForth-fast with Windows 10
32 bit Gforth and GForth-fast with Linux
64 bit Gforth and GForth-fast with Linux
vfxlin 4.71 (MPE VFX Forth) with Linux
GForth Raspberry Pi 2 (900MHz quad-core ARM Cortex-A7) with RaspbianThere was a typo in the definition of barrett reduction modulo that caused rare errors for big numbers. Now fixed.