// division of 64. In the cputicks case it's a bit more complex.
//
// For x86, on a 3 GHz machine, we'd want to divide by 3*64 to hit our target.
// To keep the division operation efficient, we round that up to 4*64, or 256.
// Given what cputicks represents, we use this on all other platforms except
// for PowerPC.
// The suggested increment frequency for PowerPC's time base register is

		m3 := h2r1

		t0 := m0.lo
		t1, c := bits.Add64(m1.lo, m0.hi, 0)
		t2, c := bits.Add64(m2.lo, m1.hi, c)
		t3, _ := bits.Add64(m3.lo, m2.hi, c)

		// Now we have the result as 4 64-bit limbs, and we need to reduce it
		// modulo 2¹³⁰ - 5. The special shape of this Crandall prime lets us do
		// a cheap partial reduction according to the reduction identity
		//