Sse roundss how get low parts?

flat assembler
Message board for the users of flat assembler.

Index > Main > Sse roundss how get low parts?

Author

Thread

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 24 Apr 2023, 09:51

Xmm1= 4.982
I want get 0.982

But I try this

Code:

 
;xmm1 = 4.982 
roundss xmm1, xmm1, 1
;do xmm1 = 4.0

Yes I could do 4.982-4 and get 0.982

But roundss not have this variant to get number after point ?
I don't want do 3 asm commands, I expected do one roundss and get watch I want.

24 Apr 2023, 09:51

macomics

Joined: 26 Jan 2021
Posts: 957
Location: Russia

macomics 24 Apr 2023, 15:27

fxtract

24 Apr 2023, 15:27

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 24 Apr 2023, 15:31

Easy write three sse commands.
Fpu three too

fld value
fxtract
fstp outmem

Strange why roundss not have option as fxtract ?

24 Apr 2023, 15:31

macomics

Joined: 26 Jan 2021
Posts: 957
Location: Russia

macomics 24 Apr 2023, 16:39

Because round <> extract

24 Apr 2023, 16:39

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 24 Apr 2023, 19:28

But it could be Smile

24 Apr 2023, 19:28

bitRAKE

Joined: 21 Jul 2003
Posts: 4043
Location: vpcmpistri

bitRAKE 24 Apr 2023, 22:14

Did you try ...

Code:

;xmm0 = 4.982
roundss xmm1, xmm0, 0x3 ; truncate
subss xmm0, xmm1
;do xmm0 = 0.982

... or maybe I misunderstand?
(roundss is all about the integer part, it only helps with fractional part through subtraction)

_________________
¯\(°_o)/¯ “languages are not safe - uses can be” Bjarne Stroustrup

24 Apr 2023, 22:14

Roman

Joined: 21 Apr 2012
Posts: 1796

Roman 25 Apr 2023, 02:45

Yes i do this.

25 Apr 2023, 02:45

< Last Thread | Next Thread >

Forum Rules:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum