And for some Mechanical binary addition
in [Embedded]
|
From: Andrew Jackson on 10 Dec 2009 04:07 >> For those who don't know Cosmac, there is no fixed PC >> and fixed stack pointer. Instead, there are 16 general >> purpose 16 bit registers, and two 4 bit registers that >> determine which registers function as the PC and the SP. >> One can do neat coroutines and subprogram calls simply >> by changing which register is the PC. > > This reminds me of an idea I once had about having a CP, a Contect Pointer. > This would be a pointer to an arbitrary RAM location where the entire > processor context is stored. This would make context switching in a > multitasking environment very fast compared to the usual pushing and popping > of all processor registers. AT&T's Hobbit processor used to do something like this. Andrew
From: invalid on 10 Dec 2009 04:27 "Meindert Sprang" <ms(a)NOJUNKcustomORSPAMware.nl> wrote in message news:4b20ab37$0$22917$e4fe514c(a)news.xs4all.nl... > "Pertti Kellomaki" <pertti.kellomaki(a)tut.fi> wrote in message > news:hfq9d5$lr3$1(a)news.cc.tut.fi... >> For those who don't know Cosmac, there is no fixed PC >> and fixed stack pointer. Instead, there are 16 general >> purpose 16 bit registers, and two 4 bit registers that >> determine which registers function as the PC and the SP. >> One can do neat coroutines and subprogram calls simply >> by changing which register is the PC. > This reminds me of an idea I once had about having a CP, a Contect > Pointer. > This would be a pointer to an arbitrary RAM location where the entire > processor context is stored. This would make context switching in a > multitasking environment very fast compared to the usual pushing and > popping > of all processor registers. ISTR that as the essence of the Texas Instruments 9900 series
From: invalid on 10 Dec 2009 04:28 "Pertti Kellomaki" <pertti.kellomaki(a)tut.fi> wrote in message news:hfqbfl$mrv$1(a)news.cc.tut.fi... > Meindert Sprang wrote: >> This reminds me of an idea I once had about having a CP, a Contect >> Pointer. >> This would be a pointer to an arbitrary RAM location where the entire >> processor context is stored. > You would love the TI TMS9900, where registers were kept in RAM: > <http://en.wikipedia.org/wiki/Texas_Instruments_TMS9900> Oops! The next posting in the thread covered the same ground!
From: Niklas Holsti on 10 Dec 2009 04:49 Meindert Sprang wrote: > "Pertti Kellomaki" <pertti.kellomaki(a)tut.fi> wrote in message > news:hfq9d5$lr3$1(a)news.cc.tut.fi... >> For those who don't know Cosmac, there is no fixed PC >> and fixed stack pointer. Instead, there are 16 general >> purpose 16 bit registers, and two 4 bit registers that >> determine which registers function as the PC and the SP. >> One can do neat coroutines and subprogram calls simply >> by changing which register is the PC. > > This reminds me of an idea I once had about having a CP, a Contect Pointer. > This would be a pointer to an arbitrary RAM location where the entire > processor context is stored. This would make context switching in a > multitasking environment very fast compared to the usual pushing and popping > of all processor registers. The Infineon C166 has a Context Pointer, and all accesses to general registers are relative to the CP. Rather like the register banks in the 8051, but not limited to four banks/contexts. -- Niklas Holsti Tidorum Ltd niklas holsti tidorum fi . @ .
From: boB on 3 Jan 2010 03:51 Don McKenzie wrote: > > And for some Mechanical binary addition > http://www.youtube.com/watch?v=GcDshWmhF4A > > Cheers Don... > > > Great fun to watch and appreciated but you still have to add up the output. I see it more as an accumulator. I suppose one could use this machine to keep score or something like that ? boB
First
|
Prev
|
Pages: 1 2 3 4 Prev: Nested interrupt Next: How hard is it to drive a 3-ph brushless motor? |