Errors returned by [driver.Valuer] implementations are now wrapped for
improved error handling during operations like [DB.Query], [DB.Exec],

	"strings"
	"testing"
	"time"
)

type testError struct{ error }

type fileOps []any // []T where T is (string | int64)

// testFile is an io.ReadWriteSeeker where the IO operations performed
// on it must match the list of operations in ops.
type testFile struct {
	ops fileOps
	pos int64
}

func (f *testFile) Read(b []byte) (int, error) {
	if len(b) == 0 {
		return 0, nil
	}
	if len(f.ops) == 0 {

	//	}
	MOVW	R1, M1
	MOVW	R1, M1

	//	LMOVW mreg ',' rreg
	//	{
	//		outcode(int($1), &$2, 0, &$4);
	//	}
	MOVW	M1, R1
	MOVW	M1, R1


	//
	// integer operations
	// logical instructions
	// shift instructions
	// unary instructions
	//
	//	LADDW rreg ',' sreg ',' rreg
	//	{
	//		outcode(int($1), &$2, int($4), &$6);
	//	}
	ADD	R1, R2, R3

		}
	}
	return 0, false
}

// ARM64RegisterShift constructs an ARM64 register with shift operation.
func ARM64RegisterShift(reg, op, count int16) (int64, error) {
	// the base register of shift operations must be general register.
	if reg > arm64.REG_R31 || reg < arm64.REG_R0 {
		return 0, errors.New("invalid register for shift operation")
	}
	return int64(reg&31)<<16 | int64(op)<<22 | int64(uint16(count)), nil
}

						t.Errorf("test %d, ReadFrom() = (%d, %v), want (%d, %v)", i, got, err, tf.wantCnt, tf.wantErr)
					}
					if len(f.ops) > 0 {
						t.Errorf("test %d, expected %d more operations", i, len(f.ops))
					}
				case testClose:
					err := tw.Close()
					if !equalError(err, tf.wantErr) {
						t.Fatalf("test %d, Close() = %v, want %v", i, err, tf.wantErr)
					}
				default:

			if !utf8.ValidRune(r) || (r == utf8.RuneError && size == 1) {
				return false, false
			}
			require = true
		}
	}
	return true, require
}

// prepare performs the bookkeeping operations required at the start of
// CreateHeader and CreateRaw.
func (w *Writer) prepare(fh *FileHeader) error {
	if w.last != nil && !w.last.closed {
		if err := w.last.close(); err != nil {
			return err
		}
	}

//
// UnreadByte returns an error if the most recent method called on the
// [Reader] was not a read operation. Notably, [Reader.Peek], [Reader.Discard], and [Reader.WriteTo] are not
// considered read operations.
func (b *Reader) UnreadByte() error {
	if b.lastByte < 0 || b.r == 0 && b.w > 0 {
		return ErrInvalidUnreadByte
	}
	// b.r > 0 || b.w == 0
	if b.r > 0 {
		b.r--
	} else {
		// b.r == 0 && b.w == 0

	// 5.3: Load and Store Instructions (RV64I)
	LD	(X5), X6				// 03b30200
	LD	4(X5), X6				// 03b34200
	SD	X5, (X6)				// 23305300
	SD	X5, 4(X6)				// 23325300

	// 7.1: Multiplication Operations
	MUL	X5, X6, X7				// b3035302
	MULH	X5, X6, X7				// b3135302
	MULHU	X5, X6, X7				// b3335302
	MULHSU	X5, X6, X7				// b3235302
	MULW	X5, X6, X7				// bb035302
	DIV	X5, X6, X7				// b3435302