Tested on a Holtek HT32F1656 with Keil and IAR.
This is due to procrastination/lazyness to wait for the slow actions of debugging on CooCox or setup a GNU environment. ARM does not have a program to issue compiler licenses to book writers, Keil (ARM) was kind enough to issue a 3 month license, and IAR issued a 1 month license after a written commitment for not using it for commercial purposes.