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School of Computer Science & Engineering
University of New South Wales
Advanced Operating Systems
COMP9242 2002/S2

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Formal Fpage Mapping Rules

Sender specifies fpage as $b$ , $s$ : fpage $[b\times2^s, (b+1)\times2^s]$ ,
Sender specifies hotspot $h$ ,
Receiver specifies fpage as $b'$ , $s'$ : fpage $[{b'}\times2^{s'}, ({b'}+1)\times2^{s'}]$ .

$s=s'$ :

mapping is $b\times2^s \mapsto b'\times2^s$
hot spot specification is not needed

$s<s'$ :

mapping is $b\times2^s \mapsto {b'}_{[63,s']} h_{[s'-1,s]} 0_{(s)}$
sender's fpage is aligned around hot spot

$s>s'$ :

mapping is ${b}_{[63,s]} h_{[s-1,s']} 0_{(s')} \mapsto b'\times2^{s'}$
receiver's fpage is aligned around hot spot

Note: The actual value of $h$ is not important, only $\relax h \bmod \max (2^s, 2^{s'})$ .

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Gernot Heiser 2002-08-07