Propeller Manual

Operators – Spin Language Reference
Here, the eight LSBs of the value of X are reversed, all other bits are set to zero and the result
is stored back in
X. The assignment form of Bitwise Reverse may also be used within
expressions for intermediate results; see Intermediate Assignments, page 147.
Note that specifying 0 as the number of bits to reverse is the same as specifying 32.
Bitwise AND ‘
&’, ‘&=’
The Bitwise AND operator performs a bitwise AND of the bits of the first operand with the
bits of the second operand. Bitwise AND can be used in both variable and integer constant
expressions, but not in floating-point constant expressions.
Each bit of the two operands is subject to the following logic:
Table 2-11: Bitwise AND Truth Table
Bit States Result
0 0 0
0 1 0
1 0 0
1 1 1
Example:
X := %00101100 & %00001111
The above example ANDs %00101100 with %00001111 and writes the result, %00001100,
to X.
Bitwise AND has an assignment form,
&=, that uses the variable to its left as both the first
operand and the result destination. For example,
X &= $F 'Short form of X := X & $F
Here, the value of X is ANDed with $F and the result is stored back in X. The assignment
form of Bitwise AND may also be used within expressions for intermediate results; see
Intermediate Assignments, page 147.
Be careful not to get Bitwise AND ‘
&’ confused with Boolean AND ‘AND’. Bitwise AND is
for bit manipulation while Boolean AND is for comparison purposes (see page 167).
Page 164 · Propeller Manual v1.1