ST20-C1 STMICROELECTRONICS [STMicroelectronics], ST20-C1 Datasheet - Page 12

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

2.3 Operators used in the definitions
address map produces the address of the byte at the bottom of the address map.
These operators are represented by the symbols ‘ ’, ‘ ’, etc.
Error conditions
Any errors that can occur in instructions which are defined in ter ms of the modulo
operators are indicated explicitly in the instruction description. For example the add
instruction indicates the cases that can cause overflow or underflow, independently of
the actual addition:
2.3.1
Type conversions
The following notation is used to indicate the type cast of x to a 16-bit integer:
If x is too large or too small to fit into a 16-bit integer then the result of the instruction is
undefined.
Double word splitting
Where a calculation is performed using a 48-bit or 64-bit value, the value may be split
into two words. The function low_word returns the least significant word and the
function high_word returns the most significant word.
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if (sum > MostPos)
{
}
else if (sum < MostNeg)
{
}
else
{
}
...
Functions
int16 (x)
Areg
Status
Status
Areg
Status
Status
Areg
Status
Status
underflo w
overflow
underflo w
overflow
underflo w
overflow
sum
clear
set
sum
set
clear
sum
clear
clear
2
2
BitsPerWord
BitsPerWord