Am 24.06.22 um 18:40 schrieb Dimiter_Popoff: <>> https://www.flickr.com/photos/137684711@N07/52167372262/in/dateposted-public/ >> >Arghh, the <> brackets ask the posting software not to insert CRLF, tabs or whatever that breaks things like URLs. This here would break if it was just a few chars longer.> Could not make out the PPC part no., was it that 404 (420?) or > something like that from IBM? I considered it at some point some > 15 or 20 years ago and got frightened by its errata sheet, was > clearly half baked at best.The chip in the photo reads PPC405 in the small print.> Which coolrunner did you use, the old Philips one or the Xilinx > version (I have used both, even wrote my own logic compiler for > the Philips one some 20-odd years ago).The Coolrunner below/left of the PPC is XILINX. I still use Coolrunners 2c64 or 128 as garbage collectors.> I remember that, but I am pretty sure the PPC was exactly that > half-baked IBM core I remember, not Motorola. Motorola did > some really good 603e spinoffs, their failure was a 7500 or something > core (could be hung by user level code so that only hard reset > would have an effect....).Reminds me at the never ending instructions in the 68040/50? that could produce exceptions in a circular way, shortly b4 Moto gave up. Oh so wonderful stuff like double-memory- indirect deferred addressing. Who says x86 is complicated? Gerhard.
another board P939
Started by ●June 22, 2022
Reply by ●June 24, 20222022-06-24
Reply by ●June 24, 20222022-06-24
Am 24.06.22 um 19:48 schrieb Dimiter_Popoff:> On 6/24/2022 20:31, Lasse Langwadt Christensen wrote:>>> Perhaps so, but Power is also free now. I have only looked at >>> risc-v docs - to begin with it is little-endian >> >> so is all the other major platforms >> >>> (a more serious > drawback than people have been made to think for >>> decades though not a show-stopper). >> >> what serious drawbacks? > > Do you have enough experience at low level programming to be able > to judge that.Oh, since 8080. The real fun starts when the CPU offers both, trying to get all the customers. And then some details like bit field insert are inconsistent with both modes. And little/big endian commes from the Gulliver book by Jonathan Swift where two tribes go to war over the question if eggs should be opened on the big or little end. In computers, it is just so important. cheers, Gerhard.
Reply by ●June 24, 20222022-06-24
On 6/25/2022 0:28, Gerhard Hoffmann wrote:> Am 24.06.22 um 19:48 schrieb Dimiter_Popoff: >> On 6/24/2022 20:31, Lasse Langwadt Christensen wrote: > >>>> Perhaps so, but Power is also free now. I have only looked at >>>> risc-v docs - to begin with it is little-endian >>> >>> so is all the other major platforms >>> >>>> (a more serious > drawback than people have been made to think for >>>> decades though not a show-stopper). >>> >>> what serious drawbacks? >> >> Do you have enough experience at low level programming to be able >> to judge that. > > Oh, since 8080.Me since the 6800 (used more the 6809 though).> > The real fun starts when the CPU offers both, trying to > get all the customers. And then some details like bit field > insert are inconsistent with both modes.Some power architecture cores do both quite well. Within our vpa toolchain you either use "move.size" (big endian) or "mover.size" (byte reversed, little endian). Neither needs extra opcodes on the cores we have used so far.> > And little/big endian commes from the Gulliver book by Jonathan > Swift where two tribes go to war over the question if eggs > should be opened on the big or little end. In computers, it is > just so important.Like I said it is no game stopper but there is what is called "network byte order", we read and write left to right, bit fields are consistently addressed only on true big endian (where bit 0 is the most significant bit) etc. All of the problems caused by little endian can be worked around and have been, of course. But one can live without these.
Reply by ●June 24, 20222022-06-24
On Fri, 24 Jun 2022 23:28:54 +0200, Gerhard Hoffmann <dk4xp@arcor.de> wrote:>Am 24.06.22 um 19:48 schrieb Dimiter_Popoff: >> On 6/24/2022 20:31, Lasse Langwadt Christensen wrote: > >>>> Perhaps so, but Power is also free now. I have only looked at >>>> risc-v docs - to begin with it is little-endian >>> >>> so is all the other major platforms >>> >>>> (a more serious > drawback than people have been made to think for >>>> decades though not a show-stopper). >>> >>> what serious drawbacks? >> >> Do you have enough experience at low level programming to be able >> to judge that. > >Oh, since 8080. > >The real fun starts when the CPU offers both, trying to >get all the customers. And then some details like bit field >insert are inconsistent with both modes. > >And little/big endian comes from the Gulliver book by Jonathan >Swift where two tribes go to war over the question if eggs >should be opened on the big or little end. In computers, it is >just so important.There is a long history. This is from the early days, when the Endian Wars broke out: .<https://www.rfc-editor.org/ien/ien137.txt> The above was first posted in "Re: the secret sauce" on 8 Jan 2021. Joe Gwinn
