Field Programmable Gate Arrays (FPGAs) can be rapidly reconfigured to provide different digital logic functions. When such FPGA logic circuits are incorporated within a stored-program computer, the result is a machine where the programmer can design both the software and the hardware that will execute that software. This paper first surveys this area of custom computing. It then describes a new custom computing architecture which uses a processing node with three sections: a standard arithmetic chip, static RAM and reconfigurable logic for operand handling. Finally an analysis of the suitability of this new approach for implementation of DSP applications shows it to be worthy of further investigation.