31 Aug
2016
31 Aug
'16
3:57 p.m.
On Aug 28, 2016, at 8:37 PM, Marc Rochkind
<rochkind(a)basepath.com> wrote:
But, as anyone who's actually programmed seriously in assembly language knows, C is
not assembler. It is a system programming language low enough to be used for things that
were once done in assembler, the most important of which is an OS.
So, for most of us, we no longer had to write in assembler. But that doesn't mean C
is assembler.
Interestingly, assembler seems to be making a come back if one gives any credence to the
Tiobe index. http://www.tiobe.com/tiobe-index/ As one who has written a lot of assembler
code and no small number of assemblers, I wouldn’t like to write in assembler again. The
problem is the lack of redundancy to catch errors.
As you all know (preaching to the choir here) the semantic model for C is the common von
Neumann architecture. With the exceptions of returning structures, the semantics map one
to one with most machines. This means that I can write C code and know pretty well what
instructions are going to be generated. This in turn means that I can use C for almost all
cases where I would have had to use assembler. The great Niklaus Wirth demonstrated this
with his Oberon and some other small languages that completely replaced the use of
assembler in his systems.
Some modern compliers have broken this, however. I have never been able to figure out what
clang is going to do. But I should expect 28,000,000 bytes of instructions to do weird
things. There’s no reason a C compiler should ever be more than about 0.25 MB of text.
Brantley Coile