MOVL (AX)(X0*1), AX             // ERROR "invalid instruction"
	MOVL (AX)(Y0*1), AX             // ERROR "invalid instruction"
	// VSIB/VM is invalid without vector index.
	// TODO(quasilyte): improve error message (#21860).
	// "invalid VSIB address (missing vector index)"
	VPGATHERQQ Y2, (BP), Y1         // ERROR "invalid instruction"
	// AVX2GATHER mask/index/dest #UD cases.

</p>

<p>
If a vector instruction takes a length or an index as an argument then it will be the
first argument.
For example, <code>VLEIF</code> <code>$1,</code> <code>$16,</code> <code>V2</code> will load
the value sixteen into index one of <code>V2</code>.
Care should be taken when using vector instructions to ensure that they are available at
runtime.

	return 0
}

// term = factor | factor ('*' | '/' | '%' | '>>' | '<<' | '&') factor
func (p *Parser) term() uint64 {
	value := p.factor()
	for {
		switch p.peek() {
		case '*':
			p.next()
			value *= p.factor()
		case '/':
			p.next()
			if int64(value) < 0 {
				p.errorf("divide of value with high bit set")
			}
			divisor := p.factor()
			if divisor == 0 {

of Extended Backus-Naur Form (EBNF):
</p>

<pre class="grammar">
Syntax      = { Production } .
Production  = production_name "=" [ Expression ] "." .
Expression  = Term { "|" Term } .
Term        = Factor { Factor } .
Factor      = production_name | token [ "…" token ] | Group | Option | Repetition .
Group       = "(" Expression ")" .
Option      = "[" Expression "]" .
Repetition  = "{" Expression "}" .
</pre>

<p>

See src/README.vendor for information on loading vendored packages

	KLMD	R2, R8                 // b93f0028
	KIMD	R0, R4                 // b93e0004
	KDSA	R0, R8                 // b93a0008
	KMA	R2, R6, R4              // b9296024
	KMCTR   R2, R6, R4              // b92d6024

	// vector add and sub instructions
	VAB	V3, V4, V4              // e743400000f3
	VAH	V3, V4, V4              // e743400010f3
	VAF	V3, V4, V4              // e743400020f3
	VAG	V3, V4, V4              // e743400030f3

	// difference that for some j, a[j]>b[j] and a[j+1]<b[j+1]. If the implementation
	// compares large chunks with wrong endianness, it gets wrong result.
	// no vector register is larger than 512 bytes for now
	const maxLength = 512
	a := make([]byte, maxLength)
	b := make([]byte, maxLength)
	// randomish but deterministic data. No 0 or 255.
	for i := 0; i < maxLength; i++ {

pkg syscall (freebsd-riscv64), const SO_USER_COOKIE = 4117 #53466
pkg syscall (freebsd-riscv64), const SO_USER_COOKIE ideal-int #53466
pkg syscall (freebsd-riscv64), const SO_VENDOR = 2147483648 #53466
pkg syscall (freebsd-riscv64), const SO_VENDOR ideal-int #53466
pkg syscall (freebsd-riscv64), const SYS_ABORT2 = 463 #53466
pkg syscall (freebsd-riscv64), const SYS_ABORT2 ideal-int #53466

		}
	} else {
		return errors.New("invalid register and extension combination")
	}
	return nil
}

// ARM64RegisterArrangement constructs an ARM64 vector register arrangement.
func ARM64RegisterArrangement(reg int16, name, arng string) (int64, error) {
	var curQ, curSize uint16
	if name[0] != 'V' {
		return 0, errors.New("expect V0 through V31; found: " + name)
	}

		{math.MaxInt64, 12, true},
		{0, 12, true},
		{math.MinInt64, 12, true},
	}

	for _, v := range vectors {
		ok := fitsInBase256(v.width, v.in)
		if ok != v.ok {
			t.Errorf("fitsInBase256(%d, %d): got %v, want %v", v.in, v.width, ok, v.ok)
		}
	}
}

func TestParseNumeric(t *testing.T) {
	vectors := []struct {
		in   string
		want int64
		ok   bool
	}{
		// Test base-256 (binary) encoded values.