}
		case lex.LSH:
			p.next()
			shift := p.factor()
			if int64(shift) < 0 {
				p.errorf("negative left shift count")
			}
			return value << shift
		case lex.RSH:
			p.next()
			shift := p.term()
			if int64(shift) < 0 {
				p.errorf("negative right shift count")
			}
			if int64(value) < 0 {
				p.errorf("right shift of value with high bit set")
			}
			value >>= shift

	{"3%0", "modulo by zero"},
	{"(1<<63)%0", "modulo of value with high bit set"},
	{"3<<-4", "negative left shift count"},
	{"3<<(1<<63)", "negative left shift count"},
	{"3>>-4", "negative right shift count"},
	{"3>>(1<<63)", "negative right shift count"},
	{"(1<<63)>>2", "right shift of value with high bit set"},
	{"(1<<62)>>2", ""},
	{`'\x80'`, "illegal UTF-8 encoding for character constant"},

a <a href="#Run_time_panics">run-time panic</a> occurs.
The shift operators implement arithmetic shifts if the left operand is a signed
integer and logical shifts if it is an unsigned integer.
There is no upper limit on the shift count. Shifts behave
as if the left operand is shifted <code>n</code> times by 1 for a shift
count of <code>n</code>.

<code>R0-&gt;16</code>
<br>
<code>R0&gt;&gt;16</code>
<br>
<code>R0&lt;&lt;16</code>
<br>
<code>R0@&gt;16</code>:
For <code>&lt;&lt;</code>, left shift <code>R0</code> by 16 bits.
The other codes are <code>-&gt;</code> (arithmetic right shift),
<code>&gt;&gt;</code> (logical right shift), and
<code>@&gt;</code> (rotate right).
</li>

<li>
<code>R0-&gt;R1</code>
<br>
<code>R0&gt;&gt;R1</code>
<br>

	ADDS	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	ADDSW	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	SUB	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"
	SUBW	R7@>2, R5, R16                                   // ERROR "unsupported shift operator"

	MOVB	R0>>8, R2          // ERROR "illegal shift"
	MOVH	R0<<16, R2         // ERROR "illegal shift"
	MOVBS	R0->8, R2          // ERROR "illegal shift"
	MOVHS	R0<<24, R2         // ERROR "illegal shift"
	MOVBU	R0->24, R2         // ERROR "illegal shift"
	MOVHU	R0@>1, R2          // ERROR "illegal shift"
	XTAB	R0>>8, R2          // ERROR "illegal shift"
	XTAH	R0<<16, R2         // ERROR "illegal shift"

		}
	}
	return 0, false
}

// ARM64RegisterShift constructs an ARM64 register with shift operation.
func ARM64RegisterShift(reg, op, count int16) (int64, error) {
	// the base register of shift operations must be general register.
	if reg > arm64.REG_R31 || reg < arm64.REG_R0 {
		return 0, errors.New("invalid register for shift operation")
	}
	return int64(reg&31)<<16 | int64(op)<<22 | int64(uint16(count)), nil
}

pkg syscall (freebsd-386), const MAP_ALIGNMENT_MASK = -16777216
pkg syscall (freebsd-386), const MAP_ALIGNMENT_MASK ideal-int
pkg syscall (freebsd-386), const MAP_ALIGNMENT_SHIFT = 24
pkg syscall (freebsd-386), const MAP_ALIGNMENT_SHIFT ideal-int
pkg syscall (freebsd-386), const MSG_CMSG_CLOEXEC = 262144
pkg syscall (freebsd-386), const MSG_CMSG_CLOEXEC ideal-int
pkg syscall (freebsd-386), const NAME_MAX = 255

	// a rune/ScanToken value for them - ugly but simple.
	LSH          ScanToken = -1000 - iota // << Left shift.
	RSH                                   // >> Logical right shift.
	ARR                                   // -> Used on ARM for shift type 3, arithmetic right shift.
	ROT                                   // @> Used on ARM for shift type 4, rotate right.
	Include                               // included file started here

../mkzip ../../zoneinfo.zip
cd ../..

files="update.bash zoneinfo.zip"
modified=true
if git diff --quiet $files; then
	modified=false
fi

if [ "$1" = "-work" ]; then
	echo Left workspace behind in work/.
	shift
else
	rm -rf work
fi

if ! $modified; then
	echo No updates needed.
	exit 0
fi

echo Updated for $CODE/$DATA: $files

commitmsg="lib/time: update to $CODE/$DATA