WSJT-X/lib/genmsk.f90
Joe Taylor 54da46da95 Starting to build JTMSK short messages into WSJT-X. Beware: this will NOT
build correctly.


git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@6413 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2016-01-21 17:53:34 +00:00

110 lines
4.0 KiB
Fortran

subroutine genmsk(msg0,ichk,msgsent,i4tone,itype)
! Encode a JTMSK message
! Input:
! - msg0 requested message to be transmitted
! - ichk if ichk=1, return only msgsent
! if ichk.ge.10000, set imsg=ichk-10000 for short msg
! - msgsent message as it will be decoded
! - i4tone array of audio tone values, 0 or 1
! - itype message type
! 1 = standard message "Call_1 Call_2 Grid/Rpt"
! 2 = type 1 prefix
! 3 = type 1 suffix
! 4 = type 2 prefix
! 5 = type 2 suffix
! 6 = free text (up to 13 characters)
! 7 = short message "<Call_1 Call2> Rpt"
use iso_c_binding, only: c_loc,c_size_t
use packjt
use hashing
character*22 msg0
character*22 message !Message to be generated
character*22 msgsent !Message as it will be received
integer*4 i4Msg6BitWords(13) !72-bit message as 6-bit words
integer*1, target:: i1Msg8BitBytes(13) !72 bits and zero tail as 8-bit bytes
integer*1 e1(198) !Encoded bits before re-ordering
integer*1 i1EncodedBits(198) !Encoded information-carrying bits
integer i4tone(234) !Tone #s, data and sync (values 0-1)
integer*1 i1hash(4)
integer b11(11)
data b11/1,1,1,0,0,0,1,0,0,1,0/ !Barker 11 code
equivalence (ihash,i1hash)
save
if(msg0(1:1).eq.'@') then !Generate a fixed tone
read(msg0(2:5),*,end=1,err=1) nfreq !at specified frequency
go to 2
1 nfreq=1000
2 i4tone(1)=nfreq
else
message=msg0
do i=1,22
if(ichar(message(i:i)).eq.0) then
message(i:)=' '
exit
endif
enddo
do i=1,22 !Strip leading blanks
if(message(1:1).ne.' ') exit
message=message(i+1:)
enddo
if(message(1:1).eq.'<') then
call genmsk_short(message,msgsent,ichk,i4tone,itype)
if(itype.lt.0) go to 999
i4tone(36)=-35
go to 999
endif
call packmsg(message,i4Msg6BitWords,itype) !Pack into 12 6-bit bytes
call unpackmsg(i4Msg6BitWords,msgsent) !Unpack to get msgsent
if(ichk.eq.1) go to 999
call entail(i4Msg6BitWords,i1Msg8BitBytes) !Add tail, make 8-bit bytes
ihash=nhash(c_loc(i1Msg8BitBytes),int(9,c_size_t),146)
ihash=2*iand(ihash,32767) !Generate the CRC
i1Msg8BitBytes(10)=i1hash(2) !CRC to bytes 10 and 11
i1Msg8BitBytes(11)=i1hash(1)
nsym=198 !(72+12+15)*2 = 198
kc=13
nc=2
nbits=87
call enc213(i1Msg8BitBytes,nbits,e1,nsym,kc,nc) !Encode the message
j=0
do i=1,nsym/2 !Reorder the encoded bits
j=j+1
i1EncodedBits(j)=e1(2*i-1)
i1EncodedBits(j+99)=e1(2*i)
enddo
! Insert three Barker 11 codes and three "even-f0-parity" bits
i4tone=0 !Start with all 0's
n1=35
n2=69
n3=94
i4tone(1:11)=b11 !11 sync bits
i4tone(11+1:11+n1)=i1EncodedBits(1:n1) !n1 data bits
nn1=count(i4tone(11+1:11+n1).eq.0) !Count the 0's
if(mod(nn1,2).eq.0) i4tone(12+n1)=1 !1 parity bit
i4tone(13+n1:23+n1)=b11 !11 sync bits
i4tone(23+n1+1:23+n1+n2)=i1EncodedBits(n1+1:n1+n2) !n2 data bits
nn2=count(i4tone(23+n1+1:23+n1+n2).eq.0) !Count the 0's
if(mod(nn2,2).eq.0) i4tone(24+n1+n2)=1 !1 parity bit
i4tone(25+n1+n2:35+n1+n2)=b11 !11 sync bits
i4tone(35+n1+n2+1:35+n1+n2+n3)=i1EncodedBits(n1+n2+1:n1+n2+n3)!n3 data bits
nn3=count(i4tone(35+n1+n2+1:35+n1+n2+n3).eq.0) !Count the 0's
if(mod(nn3,2).eq.0) i4tone(36+n1+n2+n3)=1 !1 parity bit
endif
n=count(i4tone.eq.0)
if(mod(n,2).ne.0) stop 'Parity error in genmsk.'
999 return
end subroutine genmsk