Go structs cannot embed fields with C types.

Go code cannot refer to zero-sized fields that occur at the end of
non-empty C structs. To get the address of such a field (which is the
only operation you can do with a zero-sized field) you must take the
address of the struct and add the size of the struct.

Cgo translates C types into equivalent unexported Go types.
Because the translations are unexported, a Go package should not

||    conditional OR     p || q  is  "if p then true else q"
!     NOT                !p      is  "not p"
</pre>


<h3 id="Address_operators">Address operators</h3>

<p>
For an operand <code>x</code> of type <code>T</code>, the address operation
<code>&amp;x</code> generates a pointer of type <code>*T</code> to <code>x</code>.
The operand must be <i>addressable</i>,

TEXT errors(SB),$0
	MOV	$errors(SB), (X5)		// ERROR "address load must target register"
	MOV	$8(SP), (X5)			// ERROR "address load must target register"
	MOVB	$8(SP), X5			// ERROR "unsupported address load"
	MOVH	$8(SP), X5			// ERROR "unsupported address load"
	MOVW	$8(SP), X5			// ERROR "unsupported address load"
	MOVF	$8(SP), X5			// ERROR "unsupported address load"
	MOV	$1234, 0(SP)			// ERROR "constant load must target register"

</p>

<p>
Addressing modes:
</p>

<ul>

<li>
<code>(DI)(BX*2)</code>: The location at address <code>DI</code> plus <code>BX*2</code>.
</li>

<li>
<code>64(DI)(BX*2)</code>: The location at address <code>DI</code> plus <code>BX*2</code> plus 64.
These modes accept only 1, 2, 4, and 8 as scale factors.
</li>

</ul>

<p>

	FMOVD	0x1006ff8(R1), F2	// FMOVD	16805880(R1), F2	// 3bfc7f9162ff7ffd

// very large or unaligned offset uses constant pool.
// the encoding cannot be checked as the address of the constant pool is unknown.
// here we only test that they can be assembled.
	MOVB	R1, 0x1000000(R2)	// MOVB		R1, 16777216(R2)
	MOVB	R1, 0x44332211(R2)	// MOVB		R1, 1144201745(R2)

			fmt.Fprintf(w, "ref %s %s\n", name, abi)
		}
	}
}

func (p *Parser) start(operand []lex.Token) {
	p.input = operand
	p.inputPos = 0
}

// address parses the operand into a link address structure.
func (p *Parser) address(operand []lex.Token) obj.Addr {
	p.start(operand)
	addr := obj.Addr{}
	p.operand(&addr)
	return addr
}

// parseScale converts a decimal string into a valid scale factor.

||    conditional OR     p || q  is  "if p then true else q"
!     NOT                !p      is  "not p"
</pre>


<h3 id="Address_operators">Address operators</h3>

<p>
For an operand <code>x</code> of type <code>T</code>, the address operation
<code>&amp;x</code> generates a pointer of type <code>*T</code> to <code>x</code>.
The operand must be <i>addressable</i>,

	if err != nil {
		p.errorf("bad size for DATA argument: %q", szop)
	}
	op = op[:n-2]
	nameAddr := p.address(op)
	if !p.validSymbol("DATA", &nameAddr, true) {
		return
	}
	name := symbolName(&nameAddr)

	// Operand 1 is an immediate constant or address.
	valueAddr := p.address(operands[1])
	switch valueAddr.Type {
	case obj.TYPE_CONST, obj.TYPE_FCONST, obj.TYPE_SCONST, obj.TYPE_ADDR:
		// OK

	JMP	4(X5)					// 67804200

	// CALL and JMP to symbol are encoded as JAL (using LR or ZERO
	// respectively), with a R_RISCV_JAL relocation. The linker resolves
	// the real address and updates the immediate, using a trampoline in
	// the case where the address is not directly reachable.
	CALL	asmtest(SB)				// ef000000
	JMP	asmtest(SB)				// 6f000000

	// Branch pseudo-instructions
	BEQZ	X5, 2(PC)				// 63840200