Xilinx gets ARMed up for Free

Xilinx Virtex II Pro FPGAs from the 2000’s included embedded PowerPC processor cores.

Recently ARM announced they would be providing IP for the Cortex-M1 and M3 cores for free for users of Xilinx FPGA’s.  The Cortex-M1 and M3 are some of the most basic ARM cores, taking 12-25,000 gates for the Von Neumann architecture M1 and around 43,000 for the full up Harvard architecture M3 (with full ARM THUMB instruction set support).  Xilinx already offers FPGAs/SoCs with built in ARM cores, the SYNQ series is available with a variety of high end ARM cores such as the Cortex-A53 and the RF focused R5 core.  These obviously are fairly high gate county, and cost cores, where as the M1 and M3 cores are being provided without license, and without any royalties.  Drop in the IP into your FPGA design and go.

ARM and Xilinx say this is to meet the needs of their customers, who want to be able to use the same ARM architecture in their FPGA designs as in ASICs etc, and at the lowest investment in time and cost.  This certainly makes sense, having a free ARM core is better then a low cost ARM core, and removing the ‘paperwork’ hassle helps, but that’s probably not the only reason ARM is doing this, and doing it specifically for Xilinx.

There are a couple other things at play here, ARM Mx cores are basic RISC processors, used for when you just need to get some basic processing done, no frills, low power, and easy to use.  It turns out that’s a market that is now seeing some competition from the SiFive RISC-V core.  This is a basic, easy to use RISC core, that is synthesizable into ASICS, and FPGAs, and comes with a one time low cost license fee and no royalties.  Its being used by such heavyweights as Nvidia, and could threaten the Cortex-Mx domain, so it makes sense for ARM to offer, essentially their introductory processor core, for free, as a way to sway people to the ARM ecosystem.  But why Xilinx?

Perhaps Xilinx is just the start of ARM’s plans, Xilinx is one of the biggest providers of FPGAs in the world so certainly that will help keep people in the ARM. Xilinx infact, already has a drop-in 32-bit RISC processor core available to all their customers, the MicroBlaze and PicoBlaze, of their own design.  There are also drop in 80C186 cores, MCS-51 cores, the LEON SPARC core and many others. The other big name in FPGAs is Altera, a company that has competed with Xilinx for the better part of 30-years and was, in June of 2015 bought by none other then Intel.

Altera has had a close relationship with Intel since the 1980’s when Intel first started assisting Altera with fab’ing their PLDs.

This gave Altera greater access to Intel’s fab/engineering prowess, but also to all of Intel’s IP.  Is Intel going to offer free ARM cores on Altera FPGAs (the Stratix/Arria series does include hard Cortex-A9/A53 cores already)?  It seems unlikely that they would work to support their architectural competitor any more then they have to.  It is more likely that Intel would offer some form of 32-bit x86 processor core for their FPGAs.  Now x86 isn’t exactly known for low gate counts, but it is possible.  Currently softcore 8086 and 80186 processor (the Turbo86 and Turbo186) are 22,000 and 30,000 gates respectively, really a rounding error in FPGAs that now have millions of gates. More and more, FPGAs are becoming less FPGA like, and more ‘configurable processor’ like.