carter@engr.wisc.edu (Gregory Carter) (06/19/91)
Well, first of all, it depends! My developer machine came with one installed, FPU 68881 that is, but I ordered another and it didn't come installed with one! The drive specs are wonderful, 33ms at 750K a sec. transfer time. --Greg
jansteen@cwi.nl (Jan van der Steen) (06/19/91)
carter@engr.wisc.edu (Gregory Carter) writes: >Well, first of all, it depends! >My developer machine came with one installed, FPU 68881 that is, but I ordered >another and it didn't come installed with one! >The drive specs are wonderful, 33ms at 750K a sec. transfer time. ^^^^^^^^^^^^^ Bits I presume? Jan van der Steen -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Jan van der Steen jansteen@cwi.nl Centre for Mathematics and Computer Science (CWI) Kruislaan 413, 1098 SJ Amsterdam, The Netherlands
csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) (06/19/91)
ralph@laas.fr (Ralph P. Sobek) writes: >1) As I understand the Mega STe has room for a co-processor chip. >Does the chip come installed or is it an option? I suppose that it is >a 68881, right? Is it also at 16 MHz? Do there exist compilers which >generate code for it? The 68881 is optional. The Mega STE's FPU is programmed just like the FPUs available for the standard Mega, so there should be some development packages supporting it. >2) The MegaSTe comes normally with a 48 Mb SCSI disk installed. Can >someone send me the specifications of this disk? Average seek time, >etc. ? Seagate ST157N-1, 28ms av. seek time, transfer rate 650 KB/s, autoparks. ---------------------------------------------------------------------- Claus Brod, Am Felsenkeller 2, Things. Take. Time. D-8772 Marktheidenfeld, Germany (Piet Hein) csbrod@medusa.informatik.uni-erlangen.de Claus_Brod@wue.maus.de ----------------------------------------------------------------------
micro@imada.ou.dk (Klaus Pedersen) (06/19/91)
ralph@laas.fr (Ralph P. Sobek) writes: >1) As I understand the Mega STe has room for a co-processor chip. >Does the chip come installed or is it an option? I suppose that it is >a 68881, right? Is it also at 16 MHz? Do there exist compilers which >generate code for it? Both Turbo C and HighSpeed Pascal (Maxon) support the register FPU. The libarays supplied test if the FPU is in the computer when the first floating point routine is used or in the startup code, and then uses the appriate binding... (emulating or FPU) I don't think that there is any 'automatic' binding for the TT - yet! The FPU is allways running 16 MHz... Klaus.
stigvi@Lise.Unit.NO (Stig Vidar Hovland) (06/20/91)
In article <1991Jun19.114741.11944@informatik.uni-erlangen.de>, csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) writes: |> |> The 68881 is optional. The Mega STE's FPU is programmed just like |> the FPUs available for the standard Mega, so there should be some |> development packages supporting it. |> How is it programmed on a standard Mega? Will programs written for the TT and 68882 run correctly on a Mega STE and 68881? Stig Vidar Hovland - stigvi@lise.unit.no
csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) (06/21/91)
stigvi@Lise.Unit.NO (Stig Vidar Hovland) writes: >In article <1991Jun19.114741.11944@informatik.uni-erlangen.de>, csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) writes: >|> >|> The 68881 is optional. The Mega STE's FPU is programmed just like >|> the FPUs available for the standard Mega, so there should be some >|> development packages supporting it. >|> >How is it programmed on a standard Mega? Will programs written for the TT and 68882 run correctly on a Mega STE and 68881? The FPUs available for 68000 computers are programmed via registers in memory. I don't know the base address of the FPU in a Mega, but what you do is basically write the appropiate values into a register using move instructions, then write the instruction into a instruction register, and fetch the result from a result register. This is due to the fact that the 68000 has no proper coprocessor interface like the 68020 or 68030 have. Programs that use TT FPU will use Line F instructions that won't work on a 68000. You may, however, write a Line F emulator for the standard 68000 to emulate a FPU coprocessor in the system. ---------------------------------------------------------------------- Claus Brod, Am Felsenkeller 2, Things. Take. Time. D-8772 Marktheidenfeld, Germany (Piet Hein) csbrod@medusa.informatik.uni-erlangen.de Claus_Brod@wue.maus.de ----------------------------------------------------------------------
apratt@atari.UUCP (Allan Pratt) (06/21/91)
>In article <1991Jun19.114741.11944@informatik.uni-erlangen.de>, >csbrod@immd4.informatik.uni-erlangen.de (Claus Brod) writes: >> The 68881 is optional. The Mega STE's FPU is programmed just like >> the FPUs available for the standard Mega, so there should be some >> development packages supporting it. This is correct. stigvi@Lise.Unit.NO (Stig Vidar Hovland) writes: >How is it programmed on a standard Mega? Will programs written for the >TT and 68882 run correctly on a Mega STE and 68881? No. The 68030 communicates with the FPU as a coprocessor. You use instructions like "FSIN fp0,fp1" and the CPU communicates directly with the coprocessor, telling it to take the sine of FP0 and put the answer in FP1. (FP0 and FP1 are floating-point data registers in the FPU.) The 68000 does not have this ability. With a 68000 the FPU is a peripheral, like the sound chip or floppy-disk controller: it takes many regular 68000 instructions to read and write I/O ports on the chip to get it to do what you want. You have to do it "by hand" instead of having the CPU do it for you. Thus, it is slower and your program is larger than it would be using 68030 FPU instructions. What Claus is saying is that there is an FPU peripheral that plugs into the Mega ST (called the SFP004), and there is an FPU that comes with the Mega STe, and they interface the same way. They both interface in the "peripheral" way, because that's the only way the 68000 can handle. This means that a program (or library) that runs on a Mega using the SFP004 will run on a Mega STe and use its built-in FPU. In the TT the FPU interfaces in the "coprocessor" way, so these programs won't work. ============================================ Opinions expressed above do not necessarily -- Allan Pratt, Atari Corp. reflect those of Atari Corp. or anyone else. ...ames!atari!apratt