WSJT-X/lib/ft8/genft8.f90

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subroutine genft8(msg,mygrid,bcontest,i3bit,msgsent,msgbits,itone)
! Encode an FT8 message, producing array itone().
use crc
use packjt
include 'ft8_params.f90'
character*22 msg,msgsent
character*6 mygrid
character*87 cbits
logical bcontest,checksumok
integer*4 i4Msg6BitWords(12) !72-bit message as 6-bit words
integer*1 msgbits(KK),codeword(3*ND)
integer*1, target:: i1Msg8BitBytes(11)
integer itone(NN)
integer icos7(0:6)
data icos7/2,5,6,0,4,1,3/ !Costas 7x7 tone pattern
call packmsg(msg,i4Msg6BitWords,itype,bcontest) !Pack into 12 6-bit bytes
call unpackmsg(i4Msg6BitWords,msgsent,bcontest,mygrid) !Unpack to get msgsent
write(cbits,1000) i4Msg6BitWords,32*i3bit
1000 format(12b6.6,b8.8)
read(cbits,1001) i1Msg8BitBytes(1:10)
1001 format(10b8)
i1Msg8BitBytes(10)=iand(i1Msg8BitBytes(10),128+64+32)
i1Msg8BitBytes(11)=0
icrc12=crc12(c_loc(i1Msg8BitBytes),11)
! For reference, here's how to check the CRC
! i1Msg8BitBytes(10)=icrc12/256
! i1Msg8BitBytes(11)=iand (icrc12,255)
! checksumok = crc12_check(c_loc (i1Msg8BitBytes), 11)
! if( checksumok ) write(*,*) 'Good checksum'
write(cbits,1003) i4Msg6BitWords,i3bit,icrc12
1003 format(12b6.6,b3.3,b12.12)
read(cbits,1004) msgbits
1004 format(87i1)
call encode174(msgbits,codeword) !Encode the test message
! Message structure: S7 D29 S7 D29 S7
itone(1:7)=icos7
itone(36+1:36+7)=icos7
itone(NN-6:NN)=icos7
k=7
do j=1,ND
i=3*j -2
k=k+1
if(j.eq.30) k=k+7
itone(k)=codeword(i)*4 + codeword(i+1)*2 + codeword(i+2)
enddo
return
end subroutine genft8