subroutine extractmessage144(decoded,msgreceived,nhashflag) use iso_c_binding, only: c_loc,c_size_t use packjt use hashing character*22 msgreceived 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 unpackmsg(i4Dec6BitWords,msgreceived) nhashflag=1 else msgreceived=' ' nhashflag=-1 endif return end subroutine extractmessage144