ldpcsim174_91 now works

lib/fsk4hf/extractmessage174_91.f90

@@ -0,0 +1,40 @@
+subroutine extractmessage174_91(decoded,msgreceived,ncrcflag)
+  use iso_c_binding, only: c_loc,c_size_t
+  use crc
+  use packjt
+
+  character*22 msgreceived
+  character*91 cbits
+  integer*1 decoded(91)
+  integer*1, target::  i1Dec8BitBytes(12)
+  integer*4 i4Dec6BitWords(12)
+
+! Write decoded bits into cbits: 77-bit message plus 14-bit CRC
+  write(cbits,1000) decoded
+1000 format(91i1)
+  read(cbits,1001) i1Dec8BitBytes
+1001 format(12b8)
+  read(cbits,1002) ncrc14                         !Received CRC12
+1002 format(77x,b14)
+
+  i1Dec8BitBytes(10)=iand(i1Dec8BitBytes(10),128+64+32+16+8)
+  i1Dec8BitBytes(11:12)=0
+  icrc14=crc14(c_loc(i1Dec8BitBytes),12)          !CRC12 computed from 75 msg bits
+
+  if(ncrc14.eq.icrc14 .or. sum(decoded(57:87)).eq.0) then  !### Kludge ###
+! CRC14 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 unpackmsg(i4Dec6BitWords,msgreceived,.false.,'      ')
+    ncrcflag=1
+  else
+    msgreceived=' '
+    ncrcflag=-1
+  endif 
+  return
+  end subroutine extractmessage174_91