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>.

set -e

if [ "$GOOS" = "" -o "$GOARCH" = "" ]; then
	echo "usage: GOOS=os GOARCH=arch ./bootstrap.bash [-force]" >&2
	exit 2
fi

forceflag=""
if [ "$1" = "-force" ]; then
	forceflag=-force
	shift
fi

targ="../../go-${GOOS}-${GOARCH}-bootstrap"
if [ -e $targ ]; then
	echo "$targ already exists; remove before continuing"
	exit 2
fi

unset GOROOT
src=$(cd .. && pwd)
echo "#### Copying to $targ"

	{"$1000000000", "$1000000000"},
	{"$__tsan_func_enter(SB)", "$__tsan_func_enter(SB)"},
	{"$main(SB)", "$main(SB)"},
	{"$masks<>(SB)", "$masks<>(SB)"},
	{"$setg_gcc<>(SB)", "$setg_gcc<>(SB)"},
	{"$shifts<>(SB)", "$shifts<>(SB)"},
	{"$~(1<<63)", "$9223372036854775807"},
	{"$~0x3F", "$-64"},
	{"$~15", "$-16"},
	{"(((8)&0xf)*4)(SP)", "32(SP)"},
	{"(((8-14)&0xf)*4)(SP)", "40(SP)"},
	{"(6+8)(AX)", "14(AX)"},

//	LMOVW mreg ',' rreg
//	{
//		outcode(int($1), &$2, 0, &$4);
//	}
	MOVW	M1, R1 // 40010800
	MOVV	M1, R1 // 40210800


//
// integer operations
// logical instructions
// shift instructions
// unary instructions
//
//	LADDW rreg ',' sreg ',' rreg
//	{
//		outcode(int($1), &$2, int($4), &$6);
//	}
	ADD	R5, R9, R10	// 01255020
	ADDU	R13, R14, R19	// 01cd9821

	ORW	(R1), R2              // 56201000
	ORW	-1(R1), R2            // e3201fffff56
	XOR	(R1), R2              // e32010000082
	XORW	(R1), R2              // 57201000
	XORW	-1(R1), R2            // e3201fffff57

	// shift and rotate instructions
	SRD	$4, R4, R7              // eb740004000c
	SRD	R1, R4, R7              // eb741000000c
	SRW	$4, R4, R7              // eb74000400de
	SRW	R1, R4, R7              // eb74100000de

				Content: []byte{},
				Mode:    0644,
				// Name is valid UTF-8, but format does not have UTF-8 flag set.
				// We don't do UTF-8 detection for multi-byte runes due to
				// false-positives with other encodings (e.g., Shift-JIS).
				// Format says encoding is not UTF-8, so we trust it.
				NonUTF8:  true,
				Modified: time.Date(2017, 11, 6, 13, 9, 27, 0, timeZone(-8*time.Hour)),
			},
		},
	},
	{
		Name: "utf8-osx.zip",

		b := w.AvailableBuffer()
		if w.Available() != cap(b) {
			t.Fatalf("Available() = %v, want %v", w.Available(), cap(b))
		}

		// While not recommended, it is valid to append to a shifted buffer.
		// This forces Write to copy the input.
		if rn.Intn(8) == 0 && cap(b) > 0 {
			b = b[1:1:cap(b)]
		}

		// Append a random integer of varying width.
		n := int64(rn.Intn(1 << rn.Intn(30)))

../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

			}
		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

			comment: "in the 世界",
			flags:   0x808,
		},
		{
			name:    "the replacement rune is �",
			comment: "the replacement rune is �",
			flags:   0x808,
		},
		{
			// Name is Japanese encoded in Shift JIS.
			name:    "\x93\xfa\x96{\x8c\xea.txt",
			comment: "in the 世界",
			flags:   0x008, // UTF-8 must not be set
		},
	}

	// write a zip file
	buf := new(bytes.Buffer)
	w := NewWriter(buf)