FPGA Optimized Soft Core Processors

Based on Programmable Logic Design Line article titled "Actel and ARM announce the Cortex-M1 soft processor core" (March 19, 2007)

ARM processors are widely used in the industry with applications ranging from automotive systems to wireless networking. The recent addition to their family, the 3-state pipeline Von Neumann Cortex-M1 processor, is developed with FPGA implementation in mind. It can execute Thumb code from previous generations of ARM processors (ARM7, ARM9 and ARM11), as well as compatible with the newer members of ARM's processor family - Cortex-M3, Cortex-A8, etc that support 32-bit Thumb-2 system instructions. Fast, and optimized for various FPGA devices (including Xilinx, Altera, Actel and QuickLogic), it is designed to take less FPGA fabric and produce less power.

Short history:
ARM7 - 1993, 3-stage pipeline (supports both, 32 and 16-bit ARM and Thumb instruction sets)
ARM9 - 1997, 5-stage Harvard memory architecture (32-bit RISC)
ARM11 - 2002, 8-stage Hardware memory architecture (32-bit RISC)
Cortex-M3 - 2004, 3-stage, high-performance, low cost (32-bit RISC)
Cortex-A8, 2005
Cortex-R4, 2006, 8-stage