VCT 38xxA
ADVANCE INFORMATION
3.5.4. Ghost Row Organization
Page-related ghost rows are stored in blocks of
128 Bytes. These ghost blocks are linked together
using 2-Byte ghost row pointers. The first pointer can
be found in the basic page, all following pointers are
part of the block header. A zero pointer indicates the
end of the chain.
Table 3–3: Ghost Row Identification
Row Number Tag
Row
000
001
010
011
100
101
110
111
empty
row 25
row 26
row 27
row 28
row 29
row 30
row 31
ghost
pointer
Page Table
page pointer
page 100
ghost
pointer
ghost block
4-bit designation code
3-bit row number
0000
ghost block
‘aa’
‘aa’
‘aa’
row 1
row 2
row 3 ghost row pointer
Fig. 3–6: Ghost row organization
Every ghost block contains 3 ghost rows which can be
identified by 3 row identification bytes in the block
header. The row identification contains designation
code and row number. The row number is reduced to a
3-bit tag. All ghost rows in one block belong to the
same page. If the memory manager removes a page
from memory, the linked ghost blocks will also be
removed.
8 Byte block header
40 Byte row 1 data
40 Byte row 2 data
40 Byte row 3 data
Fig. 3–7: Ghost block structure
3.5.5. Subpage Manager
READ_PAGE_INFO command will reply the page
table pointer and the actual number of subpages in
chain.
Any page in cycle can have a number of subpages,
identified by subcode. In normal mode the subpage
manager will acquire only one subpage of every
requested page. This subpage can be any if subcode
FFFF is requested or it will be selected according to
the requested subcode.
After a PAGE_REQUEST command with subcode
F1xx, the subpage manager will acquire all subpages
of the requested page but will allocate only a limited
amount of memory to store these subpages. The
parameter “page subcode low” will define the length (in
number of subpages) of a ring buffer in page memory
which will hold the recently received subpages. In this
case, the READ_PAGE_INFO command will return an
index pointing to the most recently updated subpage in
chain, together with the subcode of this page.
After a PAGE_REQUEST command with subcode
F0xx, the subpage manager will acquire all subpages
of the requested page. The subpages will be chained
in the same order as they are transmitted, i.e. every
new subcode will be added at the end of chain. The
page table entry points to the subpage which was
transmitted first after the page request. The
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