Re: [ql-users] Interesting Site
Hi Malcolm, I thought this free Coldfire hardware design might be useful. It looks like a PC104 graphics card should plug in. Thanks. It is indeed interesting. But unfortunately of no use for running QL software. E.g. at home I have a more advanced Coldfire board, which includes ISA slot and DRAM as well. Simple designs around such Coldfire chips are relatively easy, especially without graphics. (The Q40 and Q60 designs were magnitudes more challenging.) I'm sorry, but I must destroy any hopes that Coldfire CPU's (version 1) could execute our existing QL software. Not even the new announced ones with better 68k compatibility. Important instructions which behave different to 68k can not (generally) be identified or trapped out by a Coldfire CPU, in order to emulate them correctly. Absolutely not. Additionally, available QL hardware outperforms any Coldfire board emulating 68k code. So even *if* we accepted incompatibility and crashes of a lot of software, we'd have no overall performace advantage. This status is likely to remain for at least about two years. All the best Peter
Re: [ql-users] Interesting Site
Hi Nasta, I'm sorry, but I must destroy any hopes that Coldfire CPU's (version 1) could execute our existing QL software. Not even the new announced ones with better 68k compatibility. Important instructions which behave different to 68k can not (generally) be identified or trapped out by a Coldfire CPU, in order to emulate them correctly. Absolutely not. I would very much appreciate if you could give us some more details on this. Two examples for CF V4e: - mov.b xxx,-(sp)' adjusts the stack pointer by -1 - lsl and lsr set the overflow bit to the same as the carry bit Both can not be forced to trap out. What a stupidity. No way code on the CF core can solve this in general. (Except emulating the whole 68k CPU, of course.) Bye, Peter
Re: [ql-users] Interesting Site
On Thu, 3 Jan 2002, ZN wrote: the PCB design leaves a LOT to be desired. It seems that whoever did it is not very experienced. IMHO the board could have been 2/3 or even half the size. The designer actually said on the site that it was a prototype board and wasn't optimized for size or cost, and that they could easily reduce the size by that amount... Just being fair... Does anyone here have any experience with Eagle v4? What package do you folks over at Q60 HQ use? Dave
Re: [ql-users] Interesting Site
On 1/3/02 at 6:25 PM Peter Graf wrote: Hi Nasta, I'm sorry, but I must destroy any hopes that Coldfire CPU's (version 1) could execute our existing QL software. I would very much appreciate if you could give us some more details on this. Two examples for CF V4e: - mov.b xxx,-(sp)' adjusts the stack pointer by -1 - lsl and lsr set the overflow bit to the same as the carry bit Both can not be forced to trap out. What a stupidity. No way code on the CF core can solve this in general. (Except emulating the whole 68k CPU, of course.) What stupidity, indeed! I recall the first example being a bug in early 68000 silicon... looks like someone used the old source code! The second is just utterly stupid, there is no reason to do anything with the overflow bit doing LOGICAL shifts (not arithmetic). This has to be a bug. Now I'm glad I didn't go redesigning anything for the V4 coldfire... Even so, the fact remains that we have run out of 68k CPUs for the time being. We can whine about not having 68070 etc, or we can change the software that keeps being incompatible. It doesn't take much to figure out which one is the more doable. Nasta
