HSPLL mode freezes 18F46K20 micro controller
Page 31 of the datasheet has a section called "2.4.3 LP, XT, HS MODES".  It has a diagram which shows the necessary external circuitry.  By using HSPLL you are then using the HS mode with the PLL.

Page 27 has the following diagram, which I think is more helpful generally:



Then you know to what the macros are referring.