Vax 613 0S Manuel d'instructions Page 38

  • Télécharger
  • Ajouter à mon manuel
  • Imprimer
  • Page
    / 344
  • Table des matières
  • MARQUE LIVRES
  • Noté. / 5. Basé sur avis des utilisateurs
Vue de la page 37
2.1 Memory Alignment
All CPU accesses to memory have a minimum size of 32 bytes or 4 quadwords.
The 32 bytes are on a naturally aligned boundary. A TURBOchannel DMA access
of main memory can start on any naturally aligned longword boundary. A DMA
operation can be as short as one longword but cannot exceed 128 longwords.
DMA operations on data greater than 128 longwords can be performed, provided
that the requesting DMA device drop its request and rearbitrate for the
TURBOchannel every 128 longwords.
2.2 Memory Address Spaces
Table 4 lists DEC 3000 AXP memory and I/O address spaces.
Table 4 Memory Address Spaces
Start
Address End Address Size Space
0.0000.0000 0.FFFF.FFFF 4 GB Memory
1.0000.0000 1.FFFF.FFFF 4 GB TURBOchannel I/O space
2.0000.0000 3.FFFF.FFFF 8 GB Reserved
Table 5 divides memory space into its components.
Table 5 Memory Address Space Components
Start
Address End Address Size Space
0.0000.0000 0.3FFF.FFFF 1 GB Main memory
0.4000.0000 0.7FFF.FFFF 1 GB Non-cacheable memory
0.8000.0000 0.FFFF.FFFF 2 GB Tag store diagnostics
2–2 Memory and I/O Addressing
Vue de la page 37
1 2 ... 33 34 35 36 37 38 39 40 41 42 43 ... 343 344

Commentaires sur ces manuels

Pas de commentaire