ARM vs. MIPS

No one is likely to provide you a comprehensive comparison, off the cuff. It's a lot of work. And you don't really provide any guidelines about what you care about. Your question may merely be academic, but as a practical matter one difference is that the ARM machine instruction set is found on cpus from a diverse array of vendors and this suggests that if you invest your time and money in a development toolset, but later find a need to select a different processor with features you now want to have, you may find the selection of options to choose from in selecting a more fitting cpu larger and the transition using existing tools you know well less difficult to make. I like all processors nearly as well as each other, but I have a special place for MIPS in my heart because it is the first direct experience I had in developing on a truly great RISC processor design and where I had a chance to get a personal dog and pony show for a day from one of the founders, Dr. Hennessey. But I like the ARM from a business point of view, a lot.

I don't have any pointers for comparisons. I might look for them with google, but you could do that better than I could.

Jon

At the Embedded Systems Conference I sat at a table and listened to a couple of experienced guys grouse about the fact that MIPS doesn't have a standard JTAG port across all processors -- JTAG debugging is left to the chip integrator, so there isn't a common "MIPS JTAG" debugger, the way that there are for ARM.

If what I heard is true, it means that for ARM you can get debuggers all the way from $69.00 slow pokes from Macgreggor, to $2000 zippy fast ones

-- for a MIPS machine, you'd expect to pay $10000 or up.

At the Embedded Systems Conference I sat at a table and listened to a couple of experienced guys grouse about the fact that MIPS doesn't have a standard JTAG port across all processors -- JTAG debugging is left to the chip integrator, so there isn't a common "MIPS JTAG" debugger, the way that there are for ARM.

If what I heard is true, it means that for ARM you can get debuggers all the way from $69.00 slow pokes from Macgreggor, to $2000 zippy fast ones

-- for a MIPS machine, you'd expect to pay $10000 or up.

Six of one half a dozen of the other, and very few bakers in sight.

There is clearly few standard connectors for mips jtag. Probably lesser amount than there is for ARM. All jtag companies charge an arm and a leg for their tools. This is just the fact of business.

The reason that really cheap jtag adapters exist for ARM is simple - there is a lot of cheap ARM boards out there and there is demand for cheap tools. Companies like Olimex and alike provide hardware only and make good money on it too. There is less than $20 worth of parts in all of these adapters. These companies send you to openocd for software so they do not do much software work themselves.

There are very few mips boards available to developers and that is the reason of poor jtag situation.

As far as architectures go, they are very similar and I don't think there is a clear winner. I think arm is better supported with tools and such but mips is not far behind. Arm is more expensive to license comparing to mips. Mips is older architecture but it is updated to keep up with the times. MIPS32 R2 is quite good.

I personally like the fact that there are more registers in MIPS, you never run out of registers when coding in assembly. On the other hand that makes for longer context switches. R2 addresses these issues with banks of registers similar to arm but I have not seen anyone support this yet.

Over all you use what your company uses and what is cost effective. If you are small developer picking a micro controller the only real choice is ARM. There are very few general purpose MIPS controllers out there. On the other hand if you using set top chip from Broadcom for example, mips is your only choice.

Alex

aims