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|    Message 3,364 of 4,255    |
|    Joe Monk to Joe Monk    |
|    Re: segmentation    |
|    23 Oct 22 17:34:44    |
      From: joemonk64@gmail.com              On Sunday, October 23, 2022 at 7:26:51 PM UTC-5, Joe Monk wrote:       > > Since the memory to be managed is more than 64k, the OS        > > needs to effectively using huge pointers, and as such the        > > huge memory model OS needs to generate code that is        > > aware of the segment shift value.        > >       > Straight from the intel 8086 book:        >        > "In order to be dynamically relocatable, a program must not load or alter       its segment registers and must not transfer directly to a location outside the       current code segment. In other words, all offsets in the program must be       relative to fixed values        contained in the segment registers. This allows the program to be moved       anywhere in memory as long as the segment registers are updated to point to       the new base addresses."        >        Also straight from the book:              "Whenever the BIU accesses memory-to fetch an instruction or to obtain or       store a variable-it generates a physical address from a logical address. This       is done by shifting the segment base value four bit positions and adding the       offset..."              Joe              --- SoupGate-Win32 v1.05        * Origin: you cannot sedate... all the things you hate (1:229/2)    |
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