ST20C2 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
ST20C2 Datasheet PDF : 212 Pages
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word offset
0
1
slot name
le.Index
le.Count
purpose
contains the loop control variable
contains number of iterations left to perform
Table 1.2 Loop end data structure
word offset
1
0
slot name
pp.Count
pp.IptrSucc
purpose
contains unsigned count of parallel processes
contains pointer to first instr uction of successor process
Table 1.3 Parallel process data structure
word offset
2
1
0
slot name
s.Back
s.Front
s.Count
purpose
back of waiting queue
front of waiting queue
number of extra processes that the semaphore will allow to continue
running on a wait request
Table 1.4 Semaphore data structure
In addition, a number of constants are used to identify word length related values etc.;
These are listed in Table 1.5 .
Name
BitsPerByte
BitsPerWord
ByteSelectMask
WordSelectMask
BytesPerWord
MostNeg
MostPos
MostPosUnsigned
PeripheralStart
PeripheralEnd
Value
Meaning
8 The number of bits in a byte.
32 The number of bits in a word.
#00000003 Used to select the byte select bits of an address.
#FFFFFFFC Used to select the byte select bits of an address.
4 The number of bytes in a word.
#80000000 The most negative integer value.
#7FFFFFFF The most positive signed integer value.
#FFFFFFFF The most positive unsigned integer value.
#20000000 The lowest address reserved for memory-mapped on-
chip peripherals.
#3FFFFFFF The highest address reserved for memory-mapped on-
chip peripherals.
Table 1.5 Constants used in the instruction descriptions
A number of values are used by the ST20 to indicate the state of a process and other
conditions. These are listed in Table 1.6.
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