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SeryZone



Joined: 20 Dec 2013
Posts: 38
Location: Ukraine, Kryviy Rih
SeryZone
How to compare eight values in AVX register?

Code:
maxvalue qqword 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0

vcmpps ymm0, [maxvalue]
;If ymm0[] = 1
;then ymm0[] = 0            


Here. I want to replace all 1.0 to 0.0

How I can do this?
Post 07 Jun 2014, 10:37
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cod3b453



Joined: 25 Aug 2004
Posts: 619
cod3b453
Sorry I don't have a machine to test this on - vpandn might be wrong but hopefully this is enough to get the idea:
Code:
const_1p0 dd 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
const_0p0 dd 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0 

vcmpps ymm1,ymm0,qqword [const_1p0],0
                                        ; ymm1 has 1.0 mask 
vpandn ymm0,ymm1,ymm0                   ; zero 1.0 cells 
vpand ymm1,ymm1,qqword [const_0p0]      ; create 0.0 cells
vpor ymm0,ymm0,ymm1                     ; merge to complete the replacement    


Last edited by cod3b453 on 08 Jun 2014, 14:34; edited 1 time in total
Post 07 Jun 2014, 12:11
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SeryZone



Joined: 20 Dec 2013
Posts: 38
Location: Ukraine, Kryviy Rih
SeryZone
cod3b453 wrote:
Sorry I don't have a machine to test this on - vpandn might be wrong but hopefully this is enough to get the idea:
Code:
const_1p0 dd 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0
const_0p0 dd 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0

vcmpps ymm1,ymm0,[const_1p0],0
                                        ; ymm1 has 1.0 mask
vpandn ymm0,ymm1,ymm0                   ; zero 1.0 cells
vpand ymm1,ymm1,[const_0p0]             ; create 0.0 cells
vpor ymm0,ymm0,ymm1                     ; merge to complete the replacement    


operand size do not much... format MS COFF...
Post 07 Jun 2014, 12:44
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cod3b453



Joined: 25 Aug 2004
Posts: 619
cod3b453
I'd missed the "qqword" specifiers (previous snippet updated)
Post 08 Jun 2014, 14:35
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tthsqe



Joined: 20 May 2009
Posts: 724
tthsqe
Sery, this is the simplest way,
Code:
macro ReplaceOneWithZero a,b,t {
; for each i
;  if b[i] == 1.0
;   then a[i] = 0.0
;   else a[i] = b[i]
;  end if
; end for

; if a and b are the same register, t must be a different register
; if a and b are different registers, t can be the same register as a

       vcmpeqps  t,b,qqword[_ones]   ; t[i] = 0x00000000 in the case b[i]<>1.0 .  t[i] = 0xFFFFFFFF in the case b[i]=1.0 .
       vandnps   a,t,b               ; overwrite appropriate entries in a[i] with 0.0 (0x00000000)

}

align 32
_ones dd 1.0,1.0,1.0,1.0,1.0,1.0,1.0,1.0

    
Post 16 Jun 2014, 02:15
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