jdg@elmgate.UUCP (Jeff Gortatowsky) (11/14/86)
I've asked this before and never really got the response I was looking
for (I only received one or two) so I thought I'd rephrase it and try
again. Since a 68010 must emulate the coprocessor interface that a 68020
has in microcode, it must read/write to addresses in memory that the
881's registers are wired to (CIR,etc). I would like to wire up such an
interface as it's cheaper than any 020 modifications and should still be
an improvement over software FP.
I'm trying to use the Motorola guidelines for wiring an 881 to a 010. All
I need to know is what address should the base register of the 881 be
located at? Is there an official space in the Amiga memory map for an
881 in such a configuration? If not, where is a 'safe' place to put it?
I don't want to conflict with other third party hardware I may add later
if I can avoid it.
Please, no responses about how the 020 uses 'cpu space' etc. I am familiar
with the 020 and it's co-CPU interface. I just can't see spending 600
dollars for the CSA piggy back board (They told me it was going away
anyways). Thanks in advance for any information/help/tips you can
provide.
--
Jeff Gortatowsky {allegra,seismo}!rochester!kodak!elmgate!jdg
Eastman Kodak Company
<Kodak won't be responsible for the above comments, only those below>aburto@marlin.UUCP (Alfred A. Aburto) (11/18/86)
In article <535@elmgate.UUCP> jdg@elmgate.UUCP (Jeff Gortatowsky) writes: > >Please, no responses about how the 020 uses 'cpu space' etc. I am familiar >with the 020 and it's co-CPU interface. I just can't see spending 600 >dollars for the CSA piggy back board (They told me it was going away >anyways). Thanks in advance for any information/help/tips you can >provide. > > I talked to Mr. Chuck Bennett at CSA today about the 'piggy-back boards going away'. He said that this was not correct and they are still making and selling the piggy-back boards. I don't know much about the 68010/68881/Amiga interface requirements. However if the 68881 must be treated as a peripheral (like a printer or serial device) then their are certain procedures to follow (hopefully these are stated in the Amiga Hardware Manual) inorder to 'add' the device to the system. Also the AmigaDOS Exec has functions like _LVOAddDevice which may be required. The Amiga hardware device ports and registers are located at specific fixed addresses starting (I think) at $00BD0000. It is in this area that you would want the 68881 hardware port and registers to be located. Al Aburto
grr@cbmvax.cbm.UUCP (George Robbins) (11/18/86)
In article <535@elmgate.UUCP> jdg@elmgate.UUCP (Jeff Gortatowsky) writes: >I've asked this before and never really got the response I was looking >for (I only received one or two) so I thought I'd rephrase it and try >again. Since a 68010 must emulate the coprocessor interface that a 68020 >has in microcode, it must read/write to addresses in memory that the >881's registers are wired to (CIR,etc). I would like to wire up such an >interface as it's cheaper than any 020 modifications and should still be >an improvement over software FP. > >I'm trying to use the Motorola guidelines for wiring an 881 to a 010. All >I need to know is what address should the base register of the 881 be >located at? Is there an official space in the Amiga memory map for an >881 in such a configuration? If not, where is a 'safe' place to put it? >I don't want to conflict with other third party hardware I may add later >if I can avoid it. > >Jeff Gortatowsky {allegra,seismo}!rochester!kodak!elmgate!jdg As far as I know, the Amiga software only supports the 68881 when attached to a 68020. This makes your question essentially unanswerable. There is another Motorola application note that describes how to make a 68020 look like a 68000, which is probably what the CSA board is based on in the first place. -- George Robbins - now working for, uucp: {ihnp4|seismo|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@seismo.css.GOV Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)
dale@amiga.UUCP (Dale Luck) (11/18/86)
In article <841@marlin.UUCP> aburto@marlin.UUCP (Alfred A. Aburto) writes: >In article <535@elmgate.UUCP> jdg@elmgate.UUCP (Jeff Gortatowsky) writes: >> >>Please, no responses about how the 020 uses 'cpu space' etc. I am familiar >>with the 020 and it's co-CPU interface. I just can't see spending 600 > >I don't know much about the 68010/68881/Amiga interface requirements. >However if the 68881 must be treated as a peripheral (like a printer or >serial device) then their are certain procedures to follow (hopefully these >are stated in the Amiga Hardware Manual) inorder to 'add' the device to the >system. Also the AmigaDOS Exec has functions like _LVOAddDevice which may >be required. The Amiga hardware device ports and registers are located at >specific fixed addresses starting (I think) at $00BD0000. It is in this area >that you would want the 68881 hardware port and registers to be located. > If you use a 68010, there are ways (movec,moves) to access the 68881 completely transparent of the regular addresses of the amiga.