[ntp:hackers] Introconvoluted iniclude paths and the jitter program

Terje Mathisen terje.mathisen at hda.hydro.com
Mon Jan 19 22:48:33 PST 2004


David L. Mills wrote:
> machines of ancient history. That includes the Toshiba TLCS-12, the
> first automotive computer used in a Ford. It was a clone of the Digital
> PDP11, but the lawyers said it couldn't use the program counter as index
> register.

Useless trivia:

DEC patented PC-relative addressing as a cheap and easy way to allow 
relocatable/position-independent code without the overhead required by 
other methods.

Would have made it even easier to write virii, with x86 you have to 
designate one of the scarce general registers and set it up via a local 
CALL/POP sequence:

   CALL next_code
next_code:
   POP EBX	; EBX contains the (code segment) offset of next_code

Terje
-- 
- <Terje.Mathisen at hda.hydro.com>
"almost all programming can be viewed as an exercise in caching"



More information about the hackers mailing list