Re: Kernel Development & Objective-C

From: Bill Davidsen
Date: Sun Dec 02 2007 - 20:07:29 EST


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@xxxxxxx>
"Woe unto the statesman who makes war without a reason that will still
be valid when the war is over..." Otto von Bismark


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