there seems to be an error in the Intel documentation of the instruction FSINCOS. It says that the sine goes into st(0), and the cosine into st(1), whereas the reverse is true.

a search of the board turned up the following code by scronty , which has the correct usage

fsincos ;get the sin and cos of theta
fstp thetaCOS ;pop off cos(theta)
fstp thetaSIN ;pop off sin(theta)

...the sort of thing that could have you running round in circles ....;)
Posted on 2002-10-05 09:13:09 by argus
Antipasta didnt work

Can you upload a zipped version of the tutorial?
Posted on 2002-10-05 09:42:02 by dxantos
well, Topcities closed my account so I'll mail it to you if you want...
what's you e-mail?
Posted on 2002-10-05 16:15:57 by AntiPasta
argus: Intel manual says that FSINCOS stores the sine in st0 and then pushes the cosine on the top of stack, so the st0 containing sine is moved into st1 and new st0 contains the cosine.
Posted on 2002-10-05 16:24:09 by Tomasz Grysztar

i see, ...why does Intel bother telling you the route they take to get the sine into st1 and the cosine into st0 ? it's not as if you can interrupt the sequence.

also, the name of the instruction FSINCOS, with the SIN at the 1st position you would expect the sine to go into the business register, st0 ...should be FCOSSIN ...:o

thanks for explaining it ,... i've just been into the manuals to find out how the fpu shows when a sin/cos is negative (found a couple of methods)...i'm doing some graphic stuff.

ps (edit) ...i've just looked at the manual again...and the table shows the sine in st(0), and the cos in st(1).... confusing !
Posted on 2002-10-05 17:25:29 by argus

well, Topcities closed my account so I'll mail it to you if you want...

Hi, please mail it to me as well, I will offer it on my website for you and there are sure some others who will offer it on their website.


Greets YaWNS
Posted on 2002-10-05 17:32:16 by YaWNS

I have uploaded it onto my website.

You can either grab it here or you can go to my website (link below) and download it from the Stuff/Documents section.

Greets YaWNS
Posted on 2002-10-06 05:25:38 by YaWNS
Antipasta the url you provided doesnt work!!
Posted on 2002-10-09 11:57:32 by IrOn

Antipasta the url you provided doesnt work!!


maybe that is because I offer it on my site?

Posted on 2002-10-09 12:39:59 by YaWNS