On 21/11/13 17:02, Jeff Law wrote: > On 11/21/13 03:56, Brian Drummond wrote: >> On Thu, 2013-11-21 at 11:23 +0100, David Brown wrote: >>> On 21/11/13 09:22, eljedi . wrote: >>>> Thank you guys for the answers. >>>> Now I have a lot to read and learn. >>>> >>>> >>>> On Wed, Nov 20, 2013 at 8:17 PM, Oleg Endo <oleg.endo@xxxxxxxxxxx> >>>> wrote: >>>>> On Wed, 2013-11-20 at 19:25 +0100, eljedi . wrote: >>>>>> Thank you Jonathan for the quick reply. >> >>> The AVR is in fact an 8-bit cpu - I think it is the only 8-bit target >>> that is supported by gcc mainline. >>> >>> For a 16-bit cpu, look at the msp430 port. It has just recently been >>> added to mainline - previously it was developed outside the main gcc >>> tree. But being a new port, or at least a newly cleaned up port, it >>> should be a good example to start with. >> >> Excellent news! Which release version includes (or will include) the >> MSP430? > Good grief, no. Not the msp430 which has odd sized pointers. If you're > going to do a 16 bit port, do a pure one. Anything with PSImode should > be avoided as a learning experience. > > For someone trying to learn, I'd stick with one of the simple 32bit > embeded riscy processors. v850 for example. > The 20-bit pointers are only used for some msp430 devices, and even then only in "large" memory models. I haven't looked at the port code at all, but I am sure it will be possible to gloss over the 20-bit stuff when reading the code for learning purposes. Apart from the 20-bit support, the msp430 should be a pretty nice example as it has a mostly orthogonal ISA with 16 16-bit registers. And since it was updated and contributed to mainline recently by gcc experts, I expect it to be a good, modern gcc port. I have no idea about the v850, however - it may be more appropriate, despite being 32-bit rather than 16-bit. Almost certainly, it would be useful for the OP to look at more than one architecture anyway.
