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            

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    

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    

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