What's the difference between PM0056 (Cortex-M3 Programming Manual) and the ARM Cortex-M3 TRM?

[Maxpm]

PM0056 seems to describe exactly the same things as the ARM TRM. Why would I read it, instead of getting the same information from its first-party source? Is there a difference that I'm overlooking?

[waclawek.jan]

PM0056 is ought to be customized according to the configuration settings used when "instatiating" the core into silicon by the different vendors, e.g. the number of bits used for interrupts priorities, number of interrupts implemented, etc.

It indeed originates from a boilerplate text prepared by ARM, mostly as an extract of TRM and ARM.

JW