A galvanic cell is constructed with a magnesium electrode in a $1$ M MgSO$$ solution and a silver electrode in a $1$ M AgNO$$ solution. Given that the standard reduction potentials are $-2\mathrm{.}37$ V for Mg$^2/$Mg and $+0\mathrm{.}80$ V for Ag$/$Ag$,$ calculate the standard cell potential.