A89: Re: compilers


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A89: Re: compilers




If you've ever seen Motorola's manual, you'll notice that there's a bunch of
charts and stuff explaining the syntax of an opcode in 1's and 0's, like
where the register name in binary fits in, etc. All those little add.l's and
mulu.w's and whatnot are put into a long string of 1's and 0's.


That brings me to a VERY important question... how come I cannot read or
write from numerical address in as92? If I tell it:

: move.b #%10101010,#$4c00

or even

: clr.l d0
: move.b #%10101010,d0
: move.b d0,#$4c00

Including every single variaion of #'s and parenthesis I can think of (such
as #($4c00)   ), no matter what I do, I CANNOT get the silly thing to do
this without copying the address to an address register first, which is a
major pain. Am I doing something wrong?

On a related note, I can't get this to work, either:

:text1: dc.b "Hello!",0
:text2: dc.b "World!",0
:text3: dc.b "It's Me, Zeromus!",0
:
: dc.l text1,text2,text3

When I go to check what's wrong, the cursor is placed between the 't' and
the 'e' in 'text1'. Of course, without this, lookup tables don't work at
all. Any idea at all what's wrong, anyone? Is it me, or the compiler?

-Zero


----- Original Message -----
From: Zoltan Kocsi <zoltan@bendor.com.au>
To: <assembly-89@lists.ticalc.org>
Sent: Thursday, November 04, 1999 2:56 PM
Subject: A89: compilers


>
> Lynn McCartney writes:
>  > Could some one please tell me what a compiler does exactly?  I would
greatly appreciatte the help I get.  Thanks for your trouble.
>
> A compiler is a program that translates a program expressed in some
> computer language into an other, usually simpler computer language.
>
> In this regards a computer language is mostly anything that can
> describe operations done by a computer. In addition, computer
> languages are usually context free (for computers and mathematics in
> general have very limited capabilities in the context-dependent
> field).
>
> Your C compiler, for example, reads a source written in the C language
> and generates either assembly language output or direct object code.
>
> An interesting exception is that the compiler from assembly language
> (which is the human-readable machine language language closest to
> machine code, i.e. numbers) is invariably called an assembler.
>
> Often compilers are used in succession to compile something that's
> complex or fairly abstract to machine code. The C language belongs to
> the high-level languages, but it is one of the lowest level in that
> group. It is often the case that a higher level high-level language is
> compiled to C, then it is compiled to assembly then it is assembled to
> machine code.
>
> There are even trickier things, like yacc (standing for yet another
> compiler compiler) which is a compiler that compiles the yacc language
> to C. The yacc language is a language designed to describe the parsing
> part of compilers. So when you define a language, you describe the
> language in yacc and tell yacc how to generate various say FORTRAN
> constructs from your language. Yacc then generates a C code, you
> compile it and then you get a program which is a compiler that can
> reads programs written in your language and translates them to FORTRAN
> which you then can compile to assembly then machine code. There are
> much hairier scenarios sometimes. Mind boggling, isn't it :-)
>
> On a different note, it is generally accepted as a polite and
> intelligent behaviour on the Net not to use HTML or any format
> other than ASCII in email, mailing lists and USENET postings
> and to turn on word wrap at around 72-76 characters.
>
> Regards,
>
> Zoltan
>
>



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