ST20C2 Datasheet, PDF (15/212 Pages) STMicroelectronics – Instruction Set Reference Manual

Symbol
Meaning
Integer arithmetic with overflow checking
+_checked
−_checked
×_checked
Add, subtract, and multiply of signed integers. If the computation overflows an
IntegerOverflow is signalled and the result of the operation is truncated to the
word length.
Unchecked (modulo) integer arithmetic
+
Integer add, subtract, multiply, divide and remainder. If the computation over-
−
flo ws 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. The sign of the
rem
remainder is the same as the sign of the dividend.
Signed comparison operators
<
Comparisons of signed integer and floating point v alues: ‘less than’, ‘greater
>
than’, ‘less than or equal’, ‘greater than or equal’, ‘equal’ and ‘not equal’.
≤
≥
=
≠
Unsigned comparison operators
<_unsigned
>_unsigned
≥_unsigned
after
Comparisons of unsigned integer values: ‘less than’, ‘greater than’, ‘greater than
or equal’, and ‘after’ (for comparison of times).
Logical bitwise operations
∼ (or BITNOT)
∧ (or BITAND)
∨ (or BITOR)
⊗ (or BITXOR)
>>
<<
‘Not’ (1’s complement), ‘and’, ‘or’, ‘exclusive or’, and logical left and right shift
operations on bits in words.
Boolean operators
not
Boolean combination in conditionals.
and
or
Table 1.7 Operators used in the instruction descriptions
• if condition
statement
else if condition
statement
else
statement
These conditions can be nested. Braces, {}, are used to group statements which are
dependent on a condition. For example, the cj (conditional jump) instruction contains
the following lines:
if (Areg = 0)
IptrReg′ ← next instruction + n
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