The Java Language Specification, Third Edition

15.19 Shift Operators EXPRESSIONS
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15.19 Shift Operators
What, I say, is to become of those wretches?
. . . What more can you say to them than “shift for yourselves?”
—The American Crisis
The shift operators include left shift , and unsigned right
shift >>>; they are syntactically left-associative (they group left-to-right). The lefthand
operand of a shift operator is the value to be shifted; the right-hand operand
specifies the shift distance.
ShiftExpression:
AdditiveExpression
ShiftExpression > AdditiveExpression
ShiftExpression >>> AdditiveExpression
The type of each of the operands of a shift operator must be a type that is convertible
(§5.1.8) to a primitive integral type, or a compile-time error occurs.
Binary numeric promotion (§5.6.2) is not performed on the operands; rather,
unary numeric promotion (§) is performed on each operand separately. The type
of the shift expression is the promoted type of the left-hand operand.
If the promoted type of the left-hand operand is int, only the five lowestorder
bits of the right-hand operand are used as the shift distance. It is as if the
right-hand operand were subjected to a bitwise logical AND operator & (§15.22.1)
with the mask value 0x1f. The shift distance actually used is therefore always in
the range 0 to 31, inclusive.
If the promoted type of the left-hand operand is long, then only the six lowest-order
bits of the right-hand operand are used as the shift distance. It is as if the
right-hand operand were subjected to a bitwise logical AND operator & (§15.22.1)
with the mask value 0x3f. The shift distance actually used is therefore always in
the range 0 to 63, inclusive.
At run time, shift operations are performed on the two’s complement integer
representation of the value of the left operand.
The value of ns is n right-shifted s bit positions with sign-extension. The
resulting value is n 2 . For nonnegative values of n, this is equivalent to truncating
integer division, as computed by the integer division operator /, bytwoto
the power s.
The value of n>>>s is n right-shifted s bit positions with zero-extension. If n
is positive, then the result is the same as that of n>>s; ifn is negative, the result is
s
⁄
DRAFT