mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-04 16:31:17 -05:00
48 lines
1.0 KiB
Fortran
48 lines
1.0 KiB
Fortran
subroutine encode174_91_nocrc(message,codeword)
|
|
!
|
|
! Encode a 91-bit message and return a 174-bit codeword.
|
|
!
|
|
use, intrinsic :: iso_c_binding
|
|
use iso_c_binding, only: c_loc,c_size_t
|
|
use crc
|
|
|
|
integer, parameter:: N=174, K=91, M=N-K
|
|
integer*1 codeword(N)
|
|
integer*1 gen(M,K)
|
|
integer*1 message(K)
|
|
integer*1 pchecks(M)
|
|
include "ldpc_174_91_c_generator.f90"
|
|
logical first
|
|
data first/.true./
|
|
save first,gen
|
|
|
|
if( first ) then ! fill the generator matrix
|
|
gen=0
|
|
do i=1,M
|
|
do j=1,23
|
|
read(g(i)(j:j),"(Z1)") istr
|
|
ibmax=4
|
|
if(j.eq.23) ibmax=3
|
|
do jj=1, ibmax
|
|
icol=(j-1)*4+jj
|
|
if( btest(istr,4-jj) ) gen(i,icol)=1
|
|
enddo
|
|
enddo
|
|
enddo
|
|
first=.false.
|
|
endif
|
|
|
|
do i=1,M
|
|
nsum=0
|
|
do j=1,K
|
|
nsum=nsum+message(j)*gen(i,j)
|
|
enddo
|
|
pchecks(i)=mod(nsum,2)
|
|
enddo
|
|
|
|
codeword(1:K)=message
|
|
codeword(K+1:N)=pchecks
|
|
|
|
return
|
|
end subroutine encode174_91_nocrc
|