mirror of
https://github.com/saitohirga/WSJT-X.git
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101 lines
3.7 KiB
Fortran
101 lines
3.7 KiB
Fortran
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subroutine genmsk(msg0,ichk,msgsent,i4tone,itype)
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! Encode a JTMSK message
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! Input:
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! - msg0 requested message to be transmitted
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! - ichk if nonzero, return only msgsent
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! - msgsent message as it will be decoded
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! - i4tone array of audio tone values, 0 or 1
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! - itype message type
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! 1 = standard message <call1> <call2> <grid/rpt>
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! 2 = type 1 prefix
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! 3 = type 1 suffix
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! 4 = type 2 prefix
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! 5 = type 2 suffix
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! 6 = free text (up to 13 characters)
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use iso_c_binding, only: c_loc,c_size_t
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use packjt
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use hashing
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character*22 msg0
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character*22 message !Message to be generated
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character*22 msgsent !Message as it will be received
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integer*4 i4Msg6BitWords(13) !72-bit message as 6-bit words
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integer*1, target:: i1Msg8BitBytes(13) !72 bits and zero tail as 8-bit bytes
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integer*1 e1(198) !Encoded bits before re-ordering
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integer*1 i1EncodedBits(198) !Encoded information-carrying bits
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integer i4tone(234) !Tone #s, data and sync (values 0-1)
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integer*1 i1hash(4)
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integer b11(11)
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data b11/1,1,1,0,0,0,1,0,0,1,0/ !Barker 11 code
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equivalence (ihash,i1hash)
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save
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if(msg0(1:1).eq.'@') then !Generate a fixed tone
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read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency
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go to 2
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1 nfreq=1000
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2 i4tone(1)=nfreq
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else
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message=msg0
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do i=1,22
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if(ichar(message(i:i)).eq.0) then
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message(i:)=' '
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exit
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endif
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enddo
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do i=1,22 !Strip leading blanks
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if(message(1:1).ne.' ') exit
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message=message(i+1:)
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enddo
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call packmsg(message,i4Msg6BitWords,itype) !Pack into 12 6-bit bytes
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call unpackmsg(i4Msg6BitWords,msgsent) !Unpack to get msgsent
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if(ichk.ne.0) go to 999
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call entail(i4Msg6BitWords,i1Msg8BitBytes) !Add tail, make 8-bit bytes
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ihash=nhash(c_loc(i1Msg8BitBytes),int(9,c_size_t),146)
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ihash=2*iand(ihash,32767) !Generate the CRC
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i1Msg8BitBytes(10)=i1hash(2) !CRC to bytes 10 and 11
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i1Msg8BitBytes(11)=i1hash(1)
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nsym=198 !(72+12+15)*2 = 198
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kc=13
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nc=2
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nbits=87
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call enc213(i1Msg8BitBytes,nbits,e1,nsym,kc,nc) !Encode the message
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j=0
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do i=1,nsym/2 !Reorder the encoded bits
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j=j+1
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i1EncodedBits(j)=e1(2*i-1)
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i1EncodedBits(j+99)=e1(2*i)
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enddo
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! Insert three Barker 11 codes and three "even-f0-parity" bits
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i4tone=0 !Start with all 0's
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n1=35
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n2=69
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n3=94
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i4tone(1:11)=b11 !11 sync bits
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i4tone(11+1:11+n1)=i1EncodedBits(1:n1) !n1 data bits
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nn1=count(i4tone(11+1:11+n1).eq.0) !Count the 0's
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if(mod(nn1,2).eq.0) i4tone(12+n1)=1 !1 parity bit
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i4tone(13+n1:23+n1)=b11 !11 sync bits
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i4tone(23+n1+1:23+n1+n2)=i1EncodedBits(n1+1:n1+n2) !n2 data bits
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nn2=count(i4tone(23+n1+1:23+n1+n2).eq.0) !Count the 0's
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if(mod(nn2,2).eq.0) i4tone(24+n1+n2)=1 !1 parity bit
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i4tone(25+n1+n2:35+n1+n2)=b11 !11 sync bits
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i4tone(35+n1+n2+1:35+n1+n2+n3)=i1EncodedBits(n1+n2+1:n1+n2+n3)!n3 data bits
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nn3=count(i4tone(35+n1+n2+1:35+n1+n2+n3).eq.0) !Count the 0's
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if(mod(nn3,2).eq.0) i4tone(36+n1+n2+n3)=1 !1 parity bit
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endif
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n=count(i4tone.eq.0)
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if(mod(n,2).ne.0) stop 'Parity error in genmsk.'
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999 return
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end subroutine genmsk
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