register["S0"] = riscv.REG_S0
	register["S1"] = riscv.REG_S1
	register["A0"] = riscv.REG_A0
	register["A1"] = riscv.REG_A1
	register["A2"] = riscv.REG_A2
	register["A3"] = riscv.REG_A3
	register["A4"] = riscv.REG_A4
	register["A5"] = riscv.REG_A5
	register["A6"] = riscv.REG_A6
	register["A7"] = riscv.REG_A7
	register["S2"] = riscv.REG_S2
	register["S3"] = riscv.REG_S3
	register["S4"] = riscv.REG_S4

	// Expect (SB), (FP), (PC), or (SP)
	p.get('(')
	reg := p.get(scanner.Ident).String()
	p.get(')')
	p.setPseudoRegister(a, reg, isStatic, prefix)
}

// setPseudoRegister sets the NAME field of addr for a pseudo-register reference such as (SB).
func (p *Parser) setPseudoRegister(addr *obj.Addr, reg string, isStatic bool, prefix rune) {
	if addr.Reg != 0 {
		p.errorf("internal error: reg %s already set in pseudo", reg)
	}
	switch reg {

	case "CR":
		if 0 <= n && n <= 7 {
			return ppc64.REG_CR0 + n, true
		}
	case "A":
		if 0 <= n && n <= 8 {
			return ppc64.REG_A0 + n, true
		}
	case "VS":
		if 0 <= n && n <= 63 {
			return ppc64.REG_VS0 + n, true
		}
	case "V":
		if 0 <= n && n <= 31 {
			return ppc64.REG_V0 + n, true
		}
	case "F":
		if 0 <= n && n <= 31 {
			return ppc64.REG_F0 + n, true
		}
	case "R":
		if 0 <= n && n <= 31 {

	switch name {
	case "AR":
		if 0 <= n && n <= 15 {
			return s390x.REG_AR0 + n, true
		}
	case "F":
		if 0 <= n && n <= 15 {
			return s390x.REG_F0 + n, true
		}
	case "R":
		if 0 <= n && n <= 15 {
			return s390x.REG_R0 + n, true
		}
	case "V":
		if 0 <= n && n <= 31 {
			return s390x.REG_V0 + n, true
		}
	}
	return 0, false

	switch name {
	case "F":
		if 0 <= n && n <= 31 {
			return loong64.REG_F0 + n, true
		}
	case "FCSR":
		if 0 <= n && n <= 31 {
			return loong64.REG_FCSR0 + n, true
		}
	case "FCC":
		if 0 <= n && n <= 31 {
			return loong64.REG_FCC0 + n, true
		}
	case "R":
		if 0 <= n && n <= 31 {
			return loong64.REG_R0 + n, true
		}
	}
	return 0, false

		return true
	}
	return false
}

// IsARMBFX reports whether the op (as defined by an arm.A* constant) is one the
// BFX-like instructions which are in the form of "op $width, $LSB, (Reg,) Reg".
func IsARMBFX(op obj.As) bool {
	switch op {
	case arm.ABFX, arm.ABFXU, arm.ABFC, arm.ABFI:
		return true
	}
	return false
}

			// the CR bit.
			prog.Reg = a[1].Reg
			if a[1].Type != obj.TYPE_REG {
				// The CR bit is represented as a constant 0-31. Convert it to a Reg.
				c := p.getConstant(prog, op, &a[1])
				reg, success := ppc64.ConstantToCRbit(c)
				if !success {
					p.errorf("invalid CR bit register number %d", c)
				}
				prog.Reg = reg
			}
			break
		}

			"\tb\\",
			"\tc",
			"before",
			"A(1, 2, 3)",
			"after",
		),
		"before.\n.1.\n.2.\n.3.\n.after.\n",
	},
	{
		"LOAD macro",
		lines(
			"#define LOAD(off, reg) \\",
			"\tMOVBLZX	(off*4)(R12),	reg \\",
			"\tADDB	reg,		DX",
			"",
			"LOAD(8, AX)",
		),
		"\n.\n.MOVBLZX.(.8.*.4.).(.R12.).,.AX.\n.ADDB.AX.,.DX.\n",
	},
	{
		"nested multiline macro",
		lines(

// satisfies io.Seeker.
func TestReadTruncation(t *testing.T) {
	var ss []string
	for _, p := range []string{
		"testdata/gnu.tar",
		"testdata/ustar-file-reg.tar",
		"testdata/pax-path-hdr.tar",
		"testdata/sparse-formats.tar",
	} {
		buf, err := os.ReadFile(p)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		ss = append(ss, string(buf))
	}

			// still want to remove the tv_ prefix.
			// The check for "orig_" here handles orig_eax in the
			// x86 ptrace register sets, which otherwise have all fields
			// with reg_ prefixes.
			if strings.HasPrefix(n.Name, "orig_") || strings.HasPrefix(n.Name, "_") {
				continue
			}
			i := strings.Index(n.Name, "_")
			if i < 0 {
				continue
			}
			if prefix == "" {