Signed Vs Unsigned Arithmetic - Crestron SIMPL+ Reference Manual

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18 SIMPL+

Signed vs Unsigned Arithmetic

ANALOG_INPUT, ANALOG_OUTPUTs, and INTEGER in SIMPL+ are 16-bit
quantities. A 16-bit quantity can range from 0 - 65535 when it is treated without
having a sign (positive or negative). If a 16-bit number is treated as signed in
SIMPL+, the range becomes -32768 to 32767. The range from -32768 to -1 maps into
32768 to 65535. Expressed mathematically, the mapping is 65536 -
AbsoluteValue(Number). The values are treated differently depending on whether
signed or unsigned comparisons are used. Another way is as follows.
Signed 0 - 32767
Unsigned 0 - 32767
Assignments may be directly done with negative constants, for example:
INTEGER I, J;
I = -1;
J = 65535;
Results in I being equivalent to J.
Example:
IF (65535 S> 0)
X=0;
ELSE
X=1;
Above, the value of X is set to 1 since in signed arithmetic, 65535 is the same as -1,
which is not greater than 0.
IF (65535 > 0)
X=0;
ELSE
X=1;
Above, the value of X is set to 0 since in unsigned arithmetic, 65535 is greater than 0.
Crestron SIMPL+
32768 - 65535
-32768 - -1
Language Reference Guide - DOC. 5797G
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