<p>
Slice expressions construct a substring or slice from a string, array, pointer
to array, or slice. There are two variants: a simple form that specifies a low
and high bound, and a full form that also specifies a bound on the capacity.
</p>

<h4>Simple slice expressions</h4>

<p>
For a string, array, pointer to array, or slice <code>a</code>, the primary expression
</p>

<pre>

//	}
//	LTYPE1 cond imsr ',' reg
//	{
//		outcode($1, $2, &$3, 0, &$5);
//	}
	ADD	$1, R2
	ADD	R1<<R2, R3
	ADD	R1>>R2, R3
	ADD	R1@>R2, R3
	ADD	R1->R2, R3
	ADD	R1, R2

//
// MVN
//
//	LTYPE2 cond imsr ',' reg
//	{
//		outcode($1, $2, &$3, 0, &$5);
//	}
	CLZ	R1, R2

//
// MOVW
//
//	LTYPE3 cond gen ',' gen
//	{
//		outcode($1, $2, &$3, 0, &$5);
//	}

	CASPD	(R30, ZR), (RSP), (R8, R9)           // e87f3e48
	CASPW	(R6, R7), (R8), (R4, R5)             // 047d2608
	CASPD	(R2, R3), (R2), (R8, R9)             // 487c2248

// RET
	RET
	RET	foo(SB)

// B/BL/B.cond cases, and canonical names JMP, CALL.
	BL	1(PC)      // CALL 1(PC)
	BL	(R2)       // CALL (R2)
	BL	foo(SB)    // CALL foo(SB)
	BL	bar<>(SB)  // CALL bar<>(SB)
	B	foo(SB)    // JMP foo(SB)
	BEQ	1(PC)
	BEQ	2(PC)

own source code, making it easier to move the code from one location to another.
</p>

<h3 id="directives">Directives</h3>

<p>
The assembler uses various directives to bind text and data to symbol names.
For example, here is a simple complete function definition. The <code>TEXT</code>
directive declares the symbol <code>runtime·profileloop</code> and the instructions

//
//	{label:} WORD[.cond] [ arg {, arg} ] (';' | '\n')
//
// It adds any labels to p.pendingLabels and returns the word, cond,
// operand list, and true. If there is an error or EOF, it returns
// ok=false.
//
// line may reuse the memory from scratch.
func (p *Parser) line(scratch [][]lex.Token) (word, cond string, operands [][]lex.Token, ok bool) {
next:
	// Skip newlines.

bound type parameter:
</p>

<pre>
	P<sub>k</sub> ➞ A<sub>k</sub>
</pre>

<p>
A type argument <code>A<sub>k</sub></code> may be a composite type,
containing other bound type parameters <code>P<sub>k</sub></code> as element types
(or even be just another bound type parameter).
In a process of repeated simplification, the bound type parameters in each type

For example, a compiler must not invert the conditional in this program:
</p>

<pre>
*p = 1
if cond {
	*p = 2
}
</pre>

<p>
That is, the compiler must not rewrite the program into this one:
</p>

<pre>
*p = 2
if !cond {
	*p = 1
}
</pre>

<p>
If <code>cond</code> is false and another goroutine is reading <code>*p</code>,

func (p *Parser) append(prog *obj.Prog, cond string, doLabel bool) {
	if cond != "" {
		switch p.arch.Family {
		case sys.ARM:
			if !arch.ARMConditionCodes(prog, cond) {
				p.errorf("unrecognized condition code .%q", cond)
				return
			}

		case sys.ARM64:
			if !arch.ARM64Suffix(prog, cond) {
				p.errorf("unrecognized suffix .%q", cond)
				return
			}

		case sys.AMD64, sys.I386: