WSJT-X/lib/fsk4hf/extractmessage174.f90
Joe Taylor 44b4c180f6 First bare-bones decoder for FT8.
git-svn-id: svn+ssh://svn.code.sf.net/p/wsjt/wsjt/branches/wsjtx@7716 ab8295b8-cf94-4d9e-aec4-7959e3be5d79
2017-06-14 20:21:01 +00:00

53 lines
1.8 KiB
Fortran

subroutine extractmessage174(decoded,msgreceived,ncrcflag,recent_calls,nrecent)
use iso_c_binding, only: c_loc,c_size_t
use crc
use packjt
character*22 msgreceived
character*12 call1,call2
character*12 recent_calls(nrecent)
integer*1 decoded(87)
integer*1, target:: i1Dec8BitBytes(11)
integer*4 i4Dec6BitWords(12)
! Collapse 87 decoded bits to 11 bytes. Bytes 1-9 are the message, byte 10 and first half of byte 11 is the crc
do ibyte=1,9
itmp=0
do ibit=1,8
itmp=ishft(itmp,1)+iand(1,decoded((ibyte-1)*8+ibit))
enddo
i1Dec8BitBytes(ibyte)=itmp
enddo
! Need to pack the crc into bytes 10 and 11 for crc12_check
! i1Dec8BitBytes(10)=decoded(73)*8+decoded(74)*4+decoded(75)*2+decoded(76)
! i1Dec8BitBytes(11)=decoded(77)*128+decoded(78)*64+decoded(79)*2*32+decoded(80)*16
! i1Dec8BitBytes(11)=i1Dec8BitBytes(11)+decoded(81)*8+decoded(82)*4+decoded(83)*2+decoded(84)
i1Dec8BitBytes(10)=decoded(76)*8+decoded(77)*4+decoded(78)*2+decoded(79)
i1Dec8BitBytes(11)=decoded(80)*128+decoded(81)*64+decoded(82)*2*32+decoded(83)*16
i1Dec8BitBytes(11)=i1Dec8BitBytes(11)+decoded(84)*8+decoded(85)*4+decoded(86)*2+decoded(87)
! if( crc12_check(c_loc (i1Dec8BitBytes), 11) ) then
if(.true.) then !### TEST ###
! CRC12 checks out --- unpack 72-bit message
do ibyte=1,12
itmp=0
do ibit=1,6
itmp=ishft(itmp,1)+iand(1,decoded((ibyte-1)*6+ibit))
enddo
i4Dec6BitWords(ibyte)=itmp
enddo
call unpackmsg144(i4Dec6BitWords,msgreceived,call1,call2)
ncrcflag=1
if( call1(1:2) .ne. 'CQ' .and. call1(1:2) .ne. ' ' ) then
call update_recent_calls(call1,recent_calls,nrecent)
endif
if( call2(1:2) .ne. ' ' ) then
call update_recent_calls(call2,recent_calls,nrecent)
endif
else
msgreceived=' '
ncrcflag=-1
endif
return
end subroutine extractmessage174