Different PWM Duty Registers Update at the Same Time

Does ADSP-CM40xF have a register to reload updated PWM duty cycle register values at the same time across channels and PWM modules (PWM0 to 2)?

It sounds like double update mode does it, but there is not enough information in the hardware reference manual. 

Double Update Mode Enable.
In Single Update Mode, double buffering of all registers happens at the period boundary of the PWM timer. In Double Update Mode, double buffering of all registers (except delay counter registers) happens at the middle of the period as well as the beginning of the period.

If it supports, and double update mode is the one, my questions are:

  1. What is the definition of the period boundary of the PWM timer? Does it mean at the end of period?
  2. What is the register to set if I want to update all changed register values at once across all PWM module channels?