Where should I start learning Assembly?

1. i suggest diving a little into a processor architecture first. Z-80 and 8085 are almost the same, conceptually. Once you grasp the fundamentals, you can move onto x86. It too builds upon the architectures mentioned previously. Added concepts are- pipelining, segmentation etc. One of the best sources for me has been- http://www.amazon.com/Microprocessors-Principles-Application...

2. Knowing how the microprocessor works comes really handy while coding assembly as you can't 'catch exceptions' out there. It is like treading a land-mined area and nothing can replace the knowledge of the fundamental terrain- the architecture.

3. Since you know C, you can start with some serious gdb usage, as mentioned by @penberg.

4. Then find your sweet spot between these two ends. You could start with embedded robotics, another viable hobby could be IoT application. Two added advantages of these over 'theoretical' assembly language learning are that-

a) You are doing something with a real-scenario implementation, so you're surely hooked.

b) You can eventually mold a business model around it if you end up with something really innovative.

For MIPS (recommended for starting out), check out my post. It walks you through creating the initial program in C all the way through finding its vulnerability and exploiting it. The buffer overflow building is done in Python through Bowcaster. http://csmatt.com/notes/?p=96 (also check out the links at the end). Good luck!

Because Transport Tycoon is written in Assembly by Chris Sawyer. (I know, pretty amazing right?)

I found it very useful to read the Intel software developer's manual to get an understanding of the instruction set. If doing this for the x86 architecture seems too daunting at first, a fun alternative is to read the manual for the AVR microcontroller which powers the Arduino and then program an Arduino in assembly.

I would recommend picking a project that you can do only in Assembly. For me, this was creating a special waveform on a microchip controller. I had to create a custom 800kHz signal using a 16MHz clock, so there was no way other than to respect each and every clock cycle, and make the most of it.

The key is to choose a project that you are excited about. If you pick another blah assembly tutorial, without the excitement of a project pushing you, your enthusiasm will evaporate sooner or later.