TomsFastMath is a fast public domain, open source, large integer arithmetic library written in portable ISO C. It is a port of LibTomMath with optional support for inline assembler multipliers. It has the following features.

• Public domain, open source and freely accessible
• Builds with GCC [preferably v3.3.x or higher] on any 32-bit/64-bit box
• Includes ASM optimizations (inline) for
  • x86-32 (e.g. i386 and SSE2)
  • x86-64 (e.g. AMD64)
  • ARM (ARMv4 and higher)
  • PPC32 (e.g. G3/G4)
  • PPC64 (e.g. G5)
  • AVR32 (Atmel 32-bit RISC processor)
  • MIPS (32-bit)
• Includes fairly complete API (provides most of what LibTomMath provides)
• Uses similar API as LibTomMath makes porting easy
• Competitive speeds (and getting higher).
  • Faster than OpenSSL on the AMD64
  • Still room for improvements
• No heap usage (malloc/calloc/free)
• Uses only inline asm, simplifies build process, simple to add new ports