You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: spm_get_orig_coord.m
    path of file: ./repos/bspm/thirdparty/spm12/toolbox/OldNorm
    
    the code of the file until where you have to start completion: function orig_coord = spm_get_orig_coord(coord, matname,PU)
% Determine corresponding co-ordinate in un-normalised image.

    
function orig_coord = spm_get_orig_coord(coord, matname,PU)
% Determine corresponding co-ordinate in un-normalised image.
% FORMAT orig_coord = get_orig_coord2(coord, matname,PU)
% coord      - [x1 y1 z1 ; x2 y2 z2 ; etc] in MNI space (mm).
% matname    - File containing transformation information (_sn.mat).
%            - or the structure containing the transformation.
% PU         - Name of un-normalised image
% orig_coord - Co-ordinate in un-normalised image (voxel).
%
% FORMAT orig_coord = get_orig_coord2(coord, matname)
% coord      - [x1 y1 z1 ; x2 y2 z2 ; etc] in MNI space (mm).
% matname    - File containing transformation information (_sn.mat).
%            - or the structure containing the transformation.
% orig_coord - Original co-ordinate (mm).
%__________________________________________________________________________
% Copyright (C) 2008 Wellcome Trust Centre for Neuroimaging

% John Ashburner
% $Id: spm_get_orig_coord.m 4873 2012-08-30 19:06:26Z john $

if ischar(matname)
    t = load(matname);
elseif isstruct(matname)
    t = matname;
else
    error('Wrong normalisation parameters!');
end