WSJT-X/map65/libm65/setup65.f90

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subroutine setup65
! Defines arrays related to the JT65 pseudo-random synchronizing pattern.
! Executed at program start.
integer nprc(126)
common/prcom/pr(126),mdat(126),mref(126,2),mdat2(126),mref2(126,2)
! JT65
data nprc/ &
1,0,0,1,1,0,0,0,1,1,1,1,1,1,0,1,0,1,0,0, &
0,1,0,1,1,0,0,1,0,0,0,1,1,1,0,0,1,1,1,1, &
0,1,1,0,1,1,1,1,0,0,0,1,1,0,1,0,1,0,1,1, &
0,0,1,1,0,1,0,1,0,1,0,0,1,0,0,0,0,0,0,1, &
1,0,0,0,0,0,0,0,1,1,0,1,0,0,1,0,1,1,0,1, &
0,1,0,1,0,0,1,1,0,0,1,0,0,1,0,0,0,0,1,1, &
1,1,1,1,1,1/
data mr2/0/ !Silence compiler warning
! Put the appropriate pseudo-random sequence into pr
nsym=126
do i=1,nsym
pr(i)=2*nprc(i)-1
enddo
! Determine locations of data and reference symbols
k=0
mr1=0
do i=1,nsym
if(pr(i).lt.0.0) then
k=k+1
mdat(k)=i
else
mr2=i
if(mr1.eq.0) mr1=i
endif
enddo
nsig=k
! Determine the reference symbols for each data symbol.
do k=1,nsig
m=mdat(k)
mref(k,1)=mr1
do n=1,10 !Get ref symbol before data
if((m-n).gt.0) then
if (pr(m-n).gt.0.0) go to 10
endif
enddo
go to 12
10 mref(k,1)=m-n
12 mref(k,2)=mr2
do n=1,10 !Get ref symbol after data
if((m+n).le.nsym) then
if (pr(m+n).gt.0.0) go to 20
endif
enddo
go to 22
20 mref(k,2)=m+n
22 enddo
! Now do it all again, using opposite logic on pr(i)
k=0
mr1=0
do i=1,nsym
if(pr(i).gt.0.0) then
k=k+1
mdat2(k)=i
else
mr2=i
if(mr1.eq.0) mr1=i
endif
enddo
nsig=k
do k=1,nsig
m=mdat2(k)
mref2(k,1)=mr1
do n=1,10
if((m-n).gt.0) then
if (pr(m-n).lt.0.0) go to 110
endif
enddo
go to 112
110 mref2(k,1)=m-n
112 mref2(k,2)=mr2
do n=1,10
if((m+n).le.nsym) then
if (pr(m+n).lt.0.0) go to 120
endif
enddo
go to 122
120 mref2(k,2)=m+n
122 enddo
return
end subroutine setup65