mirror of
https://github.com/saitohirga/WSJT-X.git
synced 2024-11-18 10:01:57 -05:00
59 lines
1.2 KiB
Fortran
59 lines
1.2 KiB
Fortran
subroutine encode_128_90(message77,codeword)
|
|
!
|
|
! Add a 13-bit CRC to a 77-bit message and return a 128-bit codeword
|
|
!
|
|
use, intrinsic :: iso_c_binding
|
|
use iso_c_binding, only: c_loc,c_size_t
|
|
use crc
|
|
|
|
integer, parameter:: N=128, K=90, M=N-K
|
|
character*90 tmpchar
|
|
integer*1 codeword(N)
|
|
integer*1 gen(M,K)
|
|
integer*1 message77(77),message(K)
|
|
integer*1 pchecks(M)
|
|
integer*1, target :: i1MsgBytes(12)
|
|
include "ldpc_128_90_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=2
|
|
do jj=1, ibmax
|
|
icol=(j-1)*4+jj
|
|
if( btest(istr,4-jj) ) gen(i,icol)=1
|
|
enddo
|
|
enddo
|
|
enddo
|
|
first=.false.
|
|
endif
|
|
|
|
! Add 13 bit CRC to form 90-bit message+CRC13
|
|
write(tmpchar,'(77i1)') message77
|
|
tmpchar(78:80)='000'
|
|
i1MsgBytes=0
|
|
read(tmpchar,'(10b8)') i1MsgBytes(1:10)
|
|
ncrc13 = crc13 (c_loc (i1MsgBytes), 12)
|
|
write(tmpchar(78:90),'(b13)') ncrc13
|
|
read(tmpchar,'(90i1)') message
|
|
|
|
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 encode_128_90
|