I find assembly programming and debugging very easy. However I am becoming aware that perhaps I should now be thinking in terms of C to be more "modern". ..... I really find the C code very difficult to understand and follow compared to a well written and commented assembler.
Is it me, or is this a common problem with "seasoned assembler programmers". Is C the way to go ??, and if anyone has any tips to help me get my mind round this it would be appreciated.

Been there, done that. I coded assembler for who knows how many years and was 10 years ago dragged - kicking and screaming - into C.

Once you get fluent in C, you will find that your assembler experience will be extremely valuable, so many "details' in '51 C are "naturally understood" by a seasoned '51 assembly user.

You will find that C is not what you "want", some tricks are impossible - that is the hard part of the transition - but once you get used to/fluent in C you will wonder why much of what you did in assembler, you did not do in C.

I am now coding (project depending) 75-199% of a project in C and have in some instances "rescued" a project by writing "that little tricky detail that must run faster than #&))" in assembler while having the rest in C.

I started the transition by taking a Community college class in C programming (of course PC based) and then fumbled a bit till it became fluent. The book used in the community college was Kochan: "programming in ANSI C" ISBN 0-672-48408-0 and, if you do not have access to a reasonable priced "introduction to C programming class" that book should work just fine for self study for assembly programmers.

Once you have got the idea of C on the PC, get the Keil getting started guide and switch to '51 C. I think, starting off with '51 C will not be the best way, but that is my opinion.

Get going on C, you will enjoy it eventually, why delay the fun.

Erik