ACPI_ROUND_DOWN
ACPI_ROUND_DOWN (FieldBitOffset, 8));
ACPI_ROUND_DOWN (FieldByteOffset, AccessByteWidth) /
ACPI_ROUND_DOWN (NearestByteAddress, ByteAlignment);
ObjDesc->IndexField.Value = (UINT32) ACPI_ROUND_DOWN (
#define ACPI_ROUND_DOWN_TO_32BIT(a) ACPI_ROUND_DOWN(a, 4)
#define ACPI_ROUND_DOWN_TO_64BIT(a) ACPI_ROUND_DOWN(a, 8)
#define ACPI_ROUND_DOWN_TO_NATIVE_WORD(a) ACPI_ROUND_DOWN(a, sizeof(ACPI_SIZE))