🚀 go-pugleaf

In article <11348@brl-adm.ARPA> dsill@NSWC-OAS.arpa (Dave Sill) writes:
>In article <4186@eagle.ukc.ac.uk> "H.A.Shaw" <has@eagle.ukc.ac.UK> writes:
>>I wholeheartedly agree, and hope I write better C
>>programs now for three years of BASIC/PASCAL/FORTRAN/FORTH first.
>>They did teach [C] to third year Computer Scientists sometimes.
>
>This is much too late.  Computer education should proceed from a
>hardware overview to machine language to assembler language to low-
>level compiled languages on up to high-level compiled languages.
>Teaching BASIC/Pascal/FORTRAN/Forth/etc first is like teaching algebra
>before arithmetic.

Yes, but arithmetic is usually first taught without logic and the axioms of
arithmetic.  If you started your mathematics career with only the Successor
function and the few other rules you need to define arithmetic, I don't think
you would have gotten very far.  Analagously,
try teaching someone how to write a exponentiation routine with a
Turing machine (or another simplistic model of a computer).  (Just wondering:
if I wanted to drive a car would you make me build all the parts for the car
and then build the car first? :-))

Unless you have a
higher level concept of what things like lists, queues, and stacks are,
programming in assembler is extremely tough.  There are no data structures in
assembler, and this makes it tough to do any kind of non-trivial programming.
HLLs are much better at learning the fundamentals of data structures and
thinking abstractly.

>BASIC is a bad joke.  The bad habits that it imparts on students are
>particularly hard to unlearn (first impressions are lasting
>impressions).  It oversimplifies the hardware-software interface to
>the point where it seems, to the student, to be performing magic.  C
>on the other hand, is more transparent.  It allows the student to see
>the gears turning.

Unfortunately, the many of the bad habits one picks up in BASIC one also picks
up in assembler.  One of the major habits is un-structured programming.  That
is why people have a hard time going from BASIC to Pascal (for instance); the
same problem would happen going from assembler to Pascal.

Also, many of the manipulations that can be done in assembler should not
usually be done in a HLL.  About 7 years ago, I disassembled the BASIC ROMs on
my TRS-80 Model I.  I noticed a curious piece of code (which I will pseudocode
here):

0998	LOAD	(C), 0
1000	LOAD	(AB), 0112
1003	LOAD	(AB), 0212
1006	LOAD	(AB), 0312
1009	real stuff

which pseudoassembles to:
0998	12
0999	00
1000	24
1001	12
1002	01
1003	24
1004	12
1005	01
1006	24
1007	12
1008	03
1009	real stuff

And I also found statements
JMP	0998
JMP	1001
JMP	1004
JMP	1007

They were taking advantage of the fact the the 12 in 12xx in the operand field
was also the operator for LOAD (C)!  They were jumping in to the middle of
instructions (hmm... maybe this should be an argument against BASIC.  After
all, this is for an implementation of BASIC :-))

Also, machine language allows self-modifying code, which is a no-no by today's
standards.  Although some modern architectures do not allow you to do this
because of pipelining and other reasons, this is not a problem with the machine
language itself but a fault of the designing hardware for speed purposes.


Machine language is NOT the place to start learning about computers or to
program them.  HLLs have too many advantages over machine languages.  But you
are right, BASIC is not a good place to start.  What is, I don't know.  Maybe
someone out in netland does.
-- 
 _ __			NEVIN J. LIBER	..!ihnp4!ihlpf!nevin1	(312) 510-6194
' )  )				"The secret compartment of my ring I fill
 /  / _ , __o  ____		 with an Underdog super-energy pill."
/  (_</_\/ <__/ / <_	These are solely MY opinions, not AT&T's, blah blah blah