Pascal not considered harmful - was Re: Rich kids are into COBOL

[Johnny Billquist]

On 2015-02-21 01:44, ben wrote:
> On 2/20/2015 5:02 PM, Dave G4UGM wrote:
>
>> Almost all , so there exceptions,  modern compliers are written in a high
>> level language. Most use LEXX and YACC or their modern equivalents to
>> generate the program fragments needed to generate the code.
>>
>
> I would say that is 50%. If you have LEXX and YACC you tend have a
> UNIX system with a C compiler.

You don't even have that. LEX and YACC will give you the basics of the 
parsing of the source code. Everything beyond that, you still have to write.

>>> You have a front-end, which does the lexical work and translates the
>>> program into some intermediate form, such as a tree.  In the middle, you
>>> have optimization and checking--and finally, you have the back end which
>>> essentially emits code--but that doesn't necessarily imply that the
>> compiler
>>> author knows the numeric opcodes or the  precise instruction format.
>>> Many
>>> compiler backends feed into an existing assembler, which puts it all
>> together.
>
> How do handle byte operations in C like *x++ on a PDP 10?

Do you need information on how byte operations and byte pointers work on 
a PDP-10?

KCC, which is the one C compiler for the PDP-10 I sortof know something 
about, use 9 bit chars, and of course you then get four bytes to a word. 
Not sure what in your question is hard to see how it is done.

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol