Date: Mon, 11 Dec 1995 17:46:07 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: current@freebsd.org Subject: What is this thing in locore.s? Message-ID: <199512120046.RAA02243@phaeton.artisoft.com>
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The following code live in i386/i386/locore.s: ============================================================================= /* now initialize the page dir, upages, and p0stack PT */ movl $(1+UPAGES+1),%ecx /* number of PTEs */ movl %esi,%eax /* phys address of PTD */ andl $PG_FRAME,%eax /* convert to PFN, should be a NOP */ orl $PG_V|PG_KW,%eax /* valid, kernel read/write */ movl %esi,%ebx /* calculate pte offset to ptd */ shrl $PGSHIFT-2,%ebx addl %esi,%ebx /* address of page directory */ addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ fillkpt ============================================================================= What is the purpose of: ============================================================================= movl %esi,%ebx /* calculate pte offset to ptd */ shrl $PGSHIFT-2,%ebx addl %esi,%ebx /* address of page directory */ addl $((1+UPAGES+1)*NBPG),%ebx /* offset to kernel page tables */ ============================================================================= The kernel boots and runs fine without it -- it doesn't seem to do anything really useful?!? Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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