static void bitrv208neg( double* a ) {
double x1r, x1i, x2r, x2i, x3r, x3i, x4r, x4i,
x5r, x5i, x6r, x6i, x7r, x7i;
x1r = a[2];
x1i = a[3];
x2r = a[4];
x2i = a[5];
x3r = a[6];
x3i = a[7];
x4r = a[8];
x4i = a[9];
x5r = a[10];
x5i = a[11];
x6r = a[12];
x6i = a[13];
x7r = a[14];
x7i = a[15];
a[2] = x7r;
a[3] = x7i;
a[4] = x3r;
a[5] = x3i;
a[6] = x5r;
a[7] = x5i;
a[8] = x1r;
a[9] = x1i;
a[10] = x6r;
a[11] = x6i;
a[12] = x2r;
a[13] = x2i;
a[14] = x4r;
a[15] = x4i;
}