Instruction set extensions for computation on complex floating point numbers

We present a pipelined 32-bit Instruction Set Extension (ISE) for complex valued floating point operations. The ISE was implemented in the NIOS II processor, and the constraint on the number of inputs and outputs of the register bank was overcome by distributing the reads and writes of the instruction over several cycles. The hardware size was reduced by sharing hardware between instructions. The main contribution of this work is that the designed ISE performs division, multiplication, addition and subtraction on complex valued numbers. Comparing the use of the embedded multiplier and divider in a NIOS II processor to the designed ISE for an image processing problem, a speedup of 12.2 times was observed.