52 lines
1.5 KiB
Fortran
52 lines
1.5 KiB
Fortran
|
subroutine extractmessage144(decoded,msgreceived,nhashflag,recent_calls,nrecent)
|
||
|
|
use iso_c_binding, only: c_loc,c_size_t
|
||
|
|
use packjt
|
||
|
|
use hashing
|
||
|
|
|
||
|
|
character*22 msgreceived
|
||
|
|
character*12 call1,call2
|
||
|
|
character*12 recent_calls(nrecent)
|
||
|
|
integer*1 decoded(80)
|
||
|
|
integer*1, target:: i1Dec8BitBytes(10)
|
||
|
|
integer*1 i1hashdec
|
||
|
|
integer*4 i4Dec6BitWords(12)
|
||
|
|
|
||
|
|
! Collapse 80 decoded bits to 10 bytes. Bytes 1-9 are the message, byte 10 is the hash
|
||
|
|
do ibyte=1,10
|
||
|
|
itmp=0
|
||
|
|
do ibit=1,8
|
||
|
|
itmp=ishft(itmp,1)+iand(1,decoded((ibyte-1)*8+ibit))
|
||
|
|
enddo
|
||
|
|
i1Dec8BitBytes(ibyte)=itmp
|
||
|
|
enddo
|
||
|
|
|
||
|
|
! Calculate the hash using the first 9 bytes.
|
||
|
|
ihashdec=nhash(c_loc(i1Dec8BitBytes),int(9,c_size_t),146)
|
||
|
|
ihashdec=2*iand(ihashdec,255)
|
||
|
|
|
||
|
|
! Compare calculated hash with received byte 10 - if they agree, keep the message.
|
||
|
|
i1hashdec=ihashdec
|
||
|
|
if( i1hashdec .eq. i1Dec8BitBytes(10) ) then
|
||
|
|
! Good hash --- 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)
|
||
|
|
nhashflag=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=' '
|
||
|
|
nhashflag=-1
|
||
|
|
endif
|
||
|
|
return
|
||
|
|
end subroutine extractmessage144
|