}
	register["LR"] = s390x.REG_LR
	// Pseudo-registers.
	register["SB"] = RSB
	register["FP"] = RFP
	register["PC"] = RPC
	// Avoid unintentionally clobbering g using R13.
	delete(register, "R13")
	register["g"] = s390x.REG_R13
	registerPrefix := map[string]bool{
		"AR": true,
		"F":  true,
		"R":  true,
	}

	instructions := make(map[string]obj.As)
	for i, s := range obj.Anames {

)

// Reads from a reader and rot13s the result.
type rot13Reader struct {
	r io.Reader
}

func newRot13Reader(r io.Reader) *rot13Reader {
	r13 := new(rot13Reader)
	r13.r = r
	return r13
}

func (r13 *rot13Reader) Read(p []byte) (int, error) {
	n, err := r13.r.Read(p)
	for i := 0; i < n; i++ {
		c := p[i] | 0x20 // lowercase byte
		if 'a' <= c && c <= 'm' {
			p[i] += 13
		} else if 'n' <= c && c <= 'z' {

The assembler uses them to hold temporary values when assembling some instructions.
</p>

<p>
<code>R13</code> points to the <code>g</code> (goroutine) structure.
This register must be referred to as <code>g</code>; the name <code>R13</code> is not recognized.
</p>

<p>
<code>R15</code> points to the stack frame and should typically only be accessed using the

	VCVTSD2USIQ X20, R13                               // 6231ff0879ec or 6231ff2879ec or 6231ff4879ec
	VCVTSD2USIQ (CX), R13                              // 6271ff087929 or 6271ff287929 or 6271ff487929
	VCVTSD2USIQ 99(R15), R13                           // 6251ff0879af63000000 or 6251ff2879af63000000 or 6251ff4879af63000000

	VPEXTRD $64, X30, -7(DI)                           // 62637d0816b7f9ffffff40
	VPEXTRQ $27, X30, R9                               // 6243fd0816f11b
	VPEXTRQ $27, X30, R13                              // 6243fd0816f51b
	VPEXTRQ $27, X30, -15(R14)(R15*1)                  // 6203fd0816b43ef1ffffff1b
	VPEXTRQ $27, X30, -15(BX)                          // 6263fd0816b3f1ffffff1b

pkg debug/macho, type RegsAMD64 struct, R10 uint64
pkg debug/macho, type RegsAMD64 struct, R11 uint64
pkg debug/macho, type RegsAMD64 struct, R12 uint64
pkg debug/macho, type RegsAMD64 struct, R13 uint64
pkg debug/macho, type RegsAMD64 struct, R14 uint64
pkg debug/macho, type RegsAMD64 struct, R15 uint64
pkg debug/macho, type RegsAMD64 struct, R8 uint64
pkg debug/macho, type RegsAMD64 struct, R9 uint64