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Product identity values
These are values returned by the
lddevid and ldprodid instructions. For specific
product ids in the ST20 family refer to SGS-THOMSON.
1.10 Operators used in the definitions
Modulo operators
Arithmetic on addresses is done using
modulo arithmetic — i.e. there is no checking
for errors and, if the calculation overflows, the result ‘wraps around’ the range of
values representable in the word length of the processor — e.g. adding 1 to the
address at the top of the address map produces the address of the byte at the bottom
of the address map. There is also a number of instructions for performing modulo
arithmetic, such as
sum, prod, etc. These operators are represented by the symbols
‘
+’, ‘’, etc.
Name
Value
Meaning
DeviceId
Depends on pro-
cessor type. See
below.
A value used to identify the type and revision of processor.
Returned by the
ldprodid and lddevid instructions.
Disabling.p
MostNeg + #03
#80000003
Stored in the pw.State location while an alternative is being
disabled.
Enabling.p
MostNeg + #01
#80000001
Stored in the pw.State location while an alternative is being
enabled.
false
0 The boolean value ‘false’.
NoneSelected.o
-1
#FFFFFFFF
Stored in the pw.Temp slot of a process’ workspace while no
branch of an alternative has yet been selected during the
waiting and disabling phases.
NotProcess.p
MostNeg
#80000000
Used, wherever a process descriptor is expected, to indicate
that there is no process.
Ready.p
MostNeg + #03
#80000003
Stored in the pw.State location during the enabling phase of
an alternative, to indicate that a guard is ready.
TimeNotSet.p
MostNeg + #02
#80000002
Stored in pw.TLink location during enabling of a timer alter-
native after a time to wait for has been encountered.
TimeSet.p
MostNeg + #01
#80000001
Stored in pw.TLink location during enabling of a timer alter-
native after a time to wait for has been encountered.
true
1 The boolean value ‘true’.
Waiting.p
MostNeg + #02
#80000002
Stored in the pw.State location by
altwt and taltwt to indicate
that the alternative is waiting.
HighPriority
0 High priority
LowPriority
1 Low priority
Table 1.6 Constants used within the ST20