// added into the low and high halves of the 128-bit register Z (if ZINIT is
// `nil' then simply set Z, as if it were initially zero).
.macro mul0 z, zinitp, u, v0, v1, x=nil, y0=nil, y1=nil
// added into the low and high halves of the 128-bit register Z (if ZINIT is
// `nil' then simply set Z, as if it were initially zero).
.macro mul0 z, zinitp, u, v0, v1, x=nil, y0=nil, y1=nil