p.addr = p.addr[0:0]
	p.isJump = p.arch.IsJump(word)
	for _, op := range operands {
		addr := p.address(op)
		if !p.isJump && addr.Reg < 0 { // Jumps refer to PC, a pseudo.
			p.errorf("illegal use of pseudo-register in %s", word)
		}
		p.addr = append(p.addr, addr)
	}
	if p.isJump {
		p.asmJump(op, cond, p.addr)
		return
	}
	p.asmInstruction(op, cond, p.addr)

	if err := scanner.Err(); err != nil {
		t.Fatalf("error reading symbols: %v", err)
	}
	return syms
}

func runAddr2Line(t *testing.T, dbgExePath, addr string) (funcname, path, lineno string) {
	cmd := testenv.Command(t, addr2linePath(t), dbgExePath)
	cmd.Stdin = strings.NewReader(addr)
	out, err := cmd.CombinedOutput()
	if err != nil {
		t.Fatalf("go tool addr2line %v: %v\n%s", os.Args[0], err, string(out))
	}

		p.errorf("%s: expected immediate constant; found %s", op, obj.Dconv(prog, addr))
	}
	return addr.Offset
}

// getRegister checks that addr represents a register and returns its value.
func (p *Parser) getRegister(prog *obj.Prog, op obj.As, addr *obj.Addr) int16 {
	if addr.Type != obj.TYPE_REG || addr.Offset != 0 || addr.Name != 0 || addr.Index != 0 {

//	{
//		var g obj.Addr
//
//		g = nullgen;
//		g.Type = obj.TYPE_CONST;
//		g.Offset = int64($6);
//		outcode($1, $2, &$3, 0, &g);
//	}
	MOVM	0(R1), [R2,R5,R8,g] // MOVM	(R1), [R2,R5,R8,g]
	MOVM	(R1), [R2-R5] // MOVM (R1), [R2,R3,R4,R5]
	MOVM	(R1), [R2]

//	LTYPE8 cond '[' reglist ']' ',' ioreg
//	{
//		var g obj.Addr
//
//		g = nullgen;
//		g.Type = obj.TYPE_CONST;

Here's how the 386 runtime defines the 64-bit atomic load function.
</p>

<pre>
// uint64 atomicload64(uint64 volatile* addr);
// so actually
// void atomicload64(uint64 *res, uint64 volatile *addr);
TEXT runtime·atomicload64(SB), NOSPLIT, $0-12
	MOVL	ptr+0(FP), AX
	TESTL	$7, AX
	JZ	2(PC)
	MOVL	0, AX // crash with nil ptr deref
	LEAL	ret_lo+4(FP), BX