The TI-99/4A uses the TMS9900 16-bit processor. I looked it up on Wikipedia and was surprised to see that this chip requires a four-phase clock. Anyone know why

The TI-99/4A uses the TMS9900 16-bit processor. I looked it up on Wikipedia and was surprised to see that this chip requires a four-phase clock. Anyone know why it uses a four-phase clock? The reason I'm curious is that four-phase circuitry was a big thing in the late 1960s, used in mostly-forgotten early MOS computers such as the Autonetics D-200 and the Four-Phase Systems AL1 chip. But I'd be surprised to find TI using four-phase logic in 1976. See: https://en.wikipedia.org/wiki/Four-phase_logic https://en.wikipedia.org/wiki/Four-phase_logic