ST20-C1 STMICROELECTRONICS [STMicroelectronics], ST20-C1 Datasheet - Page 11

• Manufacturer Part Number: ST20-C1
• Description: Instruction Set Reference Manual
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

represent an address which is offset by x words (4 x bytes) from the address in
register . For example, in the specification of load non-local there is:
Here, Areg is loaded with the contents of the word that is n words from the address
pointed to by Areg, i.e. the word at address Areg
In all cases, if the given base address has the correct alignment then any offset used
will also give a correctly aligned address.
2.3
A full list of the operators used in the instruction definitions is given in Table 2.1.
Unless otherwise stated, all arithmetic is signed.
Modulo operators
Arithmetic 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
Symbol
>>
Areg
Operators used in the definitions
rem
and
not
>>
<<
or
arith
Table 2.1 Operators used in the instruction descriptions
word[Areg @ n]
Signed integer add, subtract, multiply, divide and remainder. If the computation
overflows the result of the operation is truncated to the word length. If a divide
or remainder by zero occurs the result of the operation is undefined. No errors
are signalled. The operator ‘ ’ is also used as a monadic operator.
Comparisons of signed integer values: ‘less than’, ‘greater than’, ‘less than or
equal’, ‘greater than or equal’, ‘equal’ and ‘not equal’.
‘Not’, ‘and’, ‘or’, ‘exclusive or’, logical left and right shift and arithmetic right shift
operations on bits in words.
Boolean combination in conditionals.
Unchecked (modulo) integer arithmetic
Signed comparison operators
Boolean operators
Bitwise operators
Meaning
4n.
2 Notation
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