ST20C2 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST20C2

Instruction Set Reference Manual

STMicroelectronics 

Name

DeviceId

Disabling.p

Enabling.p

false

NoneSelected.o

NotProcess.p

Ready.p

TimeNotSet.p

TimeSet.p

true

Waiting.p

HighPriority

LowPriority

Value

Meaning

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.

MostNeg + #03 Stored in the pw.State location while an alternative is being

#80000003 disabled.

MostNeg + #01 Stored in the pw.State location while an alternative is being

#80000001 enabled.

0 The boolean value ‘false’.

-1 Stored in the pw.Temp slot of a process’ workspace while no

#FFFFFFFF branch of an alternative has yet been selected during the

waiting and disabling phases.

MostNeg Used, wherever a process descriptor is expected, to indicate

#80000000 that there is no process.

MostNeg + #03 Stored in the pw.State location during the enabling phase of

#80000003 an alternative, to indicate that a guard is ready.

MostNeg + #02 Stored in pw.TLink location during enabling of a timer alter-

#80000002 native after a time to wait for has been encountered.

MostNeg + #01 Stored in pw.TLink location during enabling of a timer alter-

#80000001 native after a time to wait for has been encountered.

1 The boolean value ‘true’.

MostNeg + #02 Stored in the pw.State location by altwt and taltwt to indicate

#80000002 that the alternative is waiting.

0 High priority

1 Low priority

Table 1.6 Constants used within the ST20

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.

13/212

®

Share Link: