Hey,

Glad you are enjoying the series...

I just tried all the PDFs wtihin firefox and all opened up without asking for a password.   Was it the ARM ARM that was giving you issues?

I found a second link that has that document.

https://www.scss.tcd.ie/~waldroj/3d1/arm_arm.pdf

The ARM instructions are in section A3. 

Here is a quick reference card that I found online and have used on occasion.

https://users.ece.utexas.edu/~valvano/Volume1/QuickReferenceCard.pdf

Now the RPI's ARM basically has support for "regular ARM" which is like 32-bit RISC, "thumb" which has a compressed form of regular ARM in 16-bit instructions and "jazelle" which is a mode where the ARM can interpret java bytecodes. 

Regular is simple and elegant, and so is thumb from what I can see.  But I have never used it.  I've no interest in the Jazelle instructions for the time being.  Now, newer ARM processors have support for 64-bit instructions mixed with 32-bit instructions (maybe even mixed with 16-bit instructions?).  I'm not a fan of what they did there.

 If you are still getting issues, email me.  (see my profile)

Cheers,
 -- Gabriel Evenfire