Long...Re: Programming $65

[Shannen Durphey]

Mike Pitts wrote:
> 
  I wouldn't get upset with
> the poster for not taking into account my inexperience
> on the subject.

Your post happened to be the proverbial straw, nothing personal.

> 
> <<Someone, please, volunteer some clues for the guys that
> are doggedly hanging in, watching for useful stuff.  Books,
> beginner's lists, something.>>
> 
> My best advice is to learn the basics first:
> 
> What is a bit is versus a byte?
Ahh, let's see,  Bit would be a 1 or zero, byte is group of eight
bits.

> What is a nibble?
Top of my head?  Think it's 4 bits.  not too sure.

> What is indirect addressing?
Reaching, here.  Using a variable to access information in a memory
location.
> How does a microprocessor work?
Uhh.. read about 6 chapters on this, but I'm not going to try to
summarize them.

> How do numbering systems work? (binary, hex, octal)
Single digit increments until the "base" is reached, then a counter is
placed in the next column to the left, marking the "count" is higher
than base, and the counter begins again at zero. 
> What does fixed point mean?
I almost have an idea about this one, because I know I've read it.
"fixed point math vs floating point math"

> What is a stack?
Having trouble with this, but a stack is a sequence of data, in a
certain location in memory, for temporary storage of data.  What makes
it the stack, vs just memory, is that it's stored and accessed by the
processor, rather than directly by the programmer, and access is
controlled by a stack pointer. 
> What is serial data versus parallel data?
Not sure.
> What is a register?
Register.  A specific memory location, with a specific name, for
manipulation of data.
> What is a shift register?
Uhh, umm...  starting to lose me.
> What does it mean to shift a register?
I can almost remember this one, and a comment that it's an Intel
thing.
> What does it mean to rotate a register?
No idea
> What are truth tables?
I've seen these, but can't apply them to this.
> What do NAND, NOR and XOR mean?
Not AND, Not OR, ???
> What is the result of $21 XOR $01?
Not sure here, either
> What is an array?
method of using variables with the same name, but differing by numeric
designation contained in subscript.  Used them a bunch in BASIC
> What is a multidimensional array?
Never heard of it.  Unless it was the
Variablename(subscript1,subscript2) I used to use.
> How many bytes are in 1K?
Know where to look it up. wait! 1024?
> How many bytes are in 1M?  
same as above.  haven't used it enough to remember it. uhh 1M=1000K
> What is a page as it pertains to programming?
Don't know.
> What is a word as it pertains to programming?
If the processor is a 16 bit, the word size for that processor is 16
bit.  That's all I remember.
> What is a vector?
Ah, well, based on the posts over the last couple of days, I'd guess a
vector is is like GOTO that I've used.
> What is an interrupt?
I know it's a signal for the processor to stop the current
operation...
> What happens during an interrupt?
????
> What does "Programming $65" really mean. 8-)
I can use the calculator in windows to convert $65, context clues lead
me to guess it's 101.
> 
> Until you can answer these questions and literally thousands
> of other basic programming facts, reverse engineering microcode
> will not be within your domain.

Sure.  But how to remember the facts without putting them to use?  Do
you know the bore and stroke for all the Packard engines made?  Would
you remember them if you read them?  I wouldn't.  I'm not picking on
you, I'm saying that the knowledge has to relate to something or else
it's trivia.
> 
> Think of someone who doesn't know what a camshaft is, or who
> doesn't know what the term "air/fuel ratio" means.  How could
> this person rebuild or tune and engine?
Point taken.  Unfortunately it's done all the time. ; ) 
> 
> Programming is not reserved for the chosen few.  It is just
> more easily understood by the ones who have learned the skill.
> Only time and effort can result in the attainment of knowledge.
I'm here.  I am damn sure willing to invest the time and effort, and
to date have invested hundreds of dollars including internet access
time (I do little else besides subscribe to this and another mailing
list), eprom burner, software, books, an eprom eraser.  Understand me,
that's not a complaint.  I'm saying I'm not taking this lightly.  I've
got enough software and info to do efi swaps, my original reason for
subscribing to DIY_EFI, but I have no intention of quitting now.

> At least until we have the same technology as they had in the
> movie "The Matrix".  (You know, where Keaneu learned Kung Fu
> in 5 minutes).
mm, yeah.  You can lead a man to the puddle of knowledge, but you
can't make him think.
> 
> By all means, feel free to ask questions, we are all here to
> help eachother out.  But don't expect to gain the skills required
> to reverse engineer code by asking a few questions on a mailing
> list, at least until you know the basics.

Yeah.  Basics is what I'm looking for.  I'm not expecting to be handed
the skills.  That would defeat the purpose of learning.  And after I
posted this morning I realized that I haven't actually asked many
questions, so it wasn't really fair of me to send that.
So here are some Q's

Is it common for an Eprom burner to output data in hex format?

If so, why do Motorola debuggers use Sxx format?

What is Sxx format?

Can hex data be converted to Sxx format?  How?

Since learning often involves small steps, I'd like to be able to
learn some of the Motorola assy language, then make it do something,
each step building on the last.  What can I go for the "do something"
part?  Is a "simulator" any use?  Maybe some project books like the
Forest Mimms stuff?

Is there some type of "simple to complex" ladder of Motorola
processors that are closely enough related to learn on the "simple"
and move to "complex"?  Is this the long way around?

I've tried doing some Intel assy stuff out of a book, using a freeware
assembler, and the book's own programs don't work.  Are there many
variations in x86 assy language?

Again Mike, nothing personal.  Ya just heppened to hit the lottery
today. ; )  You've actually posted some good answers.
Shannen


> 

> -Mike