[Coco] Nitros9 C and maths lib

[Walter Zambotti]

I have conversion routines already written.

Yes they are PDP-11.

If you look in the follow code from OVCC you can grab the code.

https://github.com/WallyZambotti/OVCC/blob/master/mpu/fpu.c
https://github.com/WallyZambotti/OVCC/blob/master/mpu/dma.h

Walter

-----Original Message-----
From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of Jeff Teunissen
Sent: Monday, 28 October 2019 5:27 AM
To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
Subject: Re: [Coco] Nitros9 C and maths lib

Just wondering, what format are your floating point numbers in? OS-9 C (like almost every other C at the time) uses PDP-11/VAX format for its floating point numbers. It's slightly different from the little-endian IEEE
754 stuff we usually see today, but with a little massaging it's compatible.

On Mon, Oct 21, 2019, 11:39 AM Walter <zambotti at iinet.net.au> wrote:

> James
>
> Sorry missed your reply way back in July.
>
> Not sure what you mean about state but it currently is not multi 
> tasking safe.
>
> It uses a number of ports to set up pointers to the source and 
> destination values and another port to trigger the required function.
>
> As this requires several bytes written the execution could be 
> interrupted at any time and this would cause issues if more than one 
> FPU task was running at a time.
>
> I suppose I could create a wrapper around the calls that turned off 
> interrupts for the duration of the FPU call.
>
> Walter
>
> -----Original Message-----
> From: Coco [mailto:coco-bounces at maltedmedia.com] On Behalf Of James 
> Jones
> Sent: Thursday, 4 July 2019 11:31 AM
> To: CoCoList for Color Computer Enthusiasts
> Subject: Re: [Coco] Nitros9 C and maths lib
>
> Virtual FPU device? Is that documented? How much state information 
> does it keep around?
>
> On Mon, Jun 10, 2019 at 2:24 AM Walter Zambotti 
> <zambotti at iinet.net.au>
> wrote:
>
> > I have converted my raytrace program to use the virtual FPU device 
> > in
> OVCC.
> >
> >
> >
> > It improves performance by around 50 times.
> >
> >
> >
> > As I was no longer using any function (pow,sin,cos) from the 
> > standard mlib.l library I removed it from the link and it links 
> > without any issue however the floating point maths computations are 
> > all zero!!!
> >
> >
> >
> > This seems strange.  Why would I need to include a library that is 
> > no longer referenced?
> >
> >
> >
> > So if I use either of these two compile commands:
> >
> >
> >
> > cc -A raytrace.c -l=/dd/lib/mlib.l -m=8k
> >
> >
> >
> > or
> >
> >
> >
> > cc -A raytrace.c -m=8k
> >
> >
> >
> > Both compile and link without error however only the former produces 
> > correct output.
> >
> >
> >
> > Walter
> >
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > https://pairlist5.pair.net/mailman/listinfo/coco
> >
>
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