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Conference hydra::amiga_v1

Title:	AMIGA NOTES
Notice:	Join us in the NEW conference - HYDRA::AMIGA_V2
Moderator:	HYDRA::MOORE

Created:	Sat Apr 26 1986
Last Modified:	Wed Feb 05 1992
Last Successful Update:	Fri Jun 06 1997
Number of topics:	5378
Total number of notes:	38326

5010.0. "68881/2 only Boards ???" by VIVIAN::D_VISTUER () Sun Sep 01 1991 18:35

    Are there any boards on the market that will add a 68881/2 to an A500
    or B2000. I believe there was a board called the Starboard sometime
    ago, but I am looking for a newer board. Again I am not after a faster
    CPU I just want to add a F.P chip to my box.
    
    Thanks & Regards.
    
    Dave.

T.R	Title	User	Personal Name	Date	Lines
5010.1		ELWOOD::PETERS		`Sun Sep 01 1991 18:57`	9
	You need a 68020 or 68030 to add a FPU. The 68000 doesn't have the on chip support needed. The 68020/030 have hardware that decodes the FPU instructions and works with a FPU to execute them. Starboard offered a board that allowed you to Kludge a FPU but standard FPU versions of software will not work with it.
5010.2	68881 too!	SDOGUS::WILLIAMS	TOPGUN	`Sun Sep 01 1991 23:34`	11
	> You need a 68020 or 68030 to add a FPU. The 68000 doesn't have >the on chip support needed. The 68020/030 have hardware that decodes >the FPU instructions and works with a FPU to execute them. It is my belief that the 68881 is infact usable with a 68000, but as an I/O device rather than a co-processor (takes some funny special software to do this). This is long ago ancient history info, so I could be wrong. (Memory is the second think to go!) Clark
5010.3		BOMBE::MOORE	Amiga: Where 'multimedia' REALLY began	`Tue Sep 03 1991 05:09`	2
	I believe the old CMI Processor Accelerator (16MHz 68000) included a socket for an optional 68881.
5010.4	68881 will work with the 68K	HSSTPT::WILSONTL	Lead Trumpet (Read that...LEED!)	`Tue Sep 03 1991 15:49`	5
	Don't know if it requires special software, though. I suspect it does. I have a Spirit Technologies In-Mate 500 which contains space for 8 megs, a SCSI con- troller and a socket for a 68881. Tony
5010.5		ELWOOD::PETERS		`Tue Sep 03 1991 18:26`	9
	I guess I was not clear in .1 . For FPU versions of software to work, you need a 68020/030 to work with a 68881/882 . All the expansion boards that have sockets for a FPU with a 68000 need CUSTOM software. Steve P.
5010.6	Available thru the magic of shared libraries	TLE::RMEYERS	Randy Meyers	`Thu Sep 05 1991 00:08`	9
	Re: .5 You don't really need any custom application software to use an FPU with a 68000. The folks that sold boards to make it work supplied a replacement mathieeedoubbas.library that used the FPU as an I/O device to do the calculations. So, programs that are written for normal Amiga software floating point use the FPU chip without any changes. The result isn't as fast as using the 020 or 030 co-processer interface.