Re: Kernel Development & Objective-C

Bill Davidsen
2007-12-03T01:07:28Z

Alan Cox wrote:
>> Well, original C allowed you to do what you wanted with pointers (I used
>> to teach that back when K&R was "the" C manual). Now people which about
>> having pointers outside the array, which is a crock in practice, as long
>> as you don't actually /use/ an out of range value.
>>
>
> Actually the standards had good reasons to bar this use, because many
> runtime environments used segmentation and unsigned segment offsets. On a
> 286 you could get into quite a mess with out of array reference tricks.
>
>
>> variable with the address of the start. I was more familiar with the B
>> stuff, I wrote both the interpreter and the code generator+library for
>> the 8080 and GE600 machines. B on MULTICS, those were the days... :-D
>>
>
> B on Honeywell L66, so that may well have been a relative of your code
> generator ?
>
>
Probably the Bell Labs one. I did an optimizer on the Pcode which caught
jumps to jumps, then had separate 8080 and L66 code generators into GMAP
on the GE and the CP/M assembler or the Intel (ISIS) assembler for 8080.
There was also an 8085 code generator using the "ten undocumented
instructions" from the Dr Dobbs article. GE actually had a contract with
Intel to provide CPUs with those instructions, and we used them in the
Terminet(r) printers.

Those were the days ;-)

--
Bill Davidsen <davidsen@tmr.com>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark