Texas Instruments TI89 Developer Guide - Page 75

Chapter 7: Flash Application Layout 33 7.1.3. 7.1.3.1. 7.1.3.2. Application Header The OS keeps track of apps through the application header. The application header contains information about the application itself. The header contains the internal name of the application, flags, the length of the application's data segment, an offset to the beginning of application code, an offset to the beginning of initial data, and the length of initial data. Lengths and offsets are stored most significant byte first - the convention used in the Motorola 68000 microprocessor. This header is created by the MKAPPLET utility. The following fields may be accessed through the AppHdr structure. Offset Length (bytes) (bytes) Contents 0 4 magic number (0x167B533D) 4 8 internal application name (padded with trailing zeros to eight bytes) 12 24 reserved (fill with zeros) 36 2 flags 38 4 length of data segment 42 4 byte offset to code segment 46 4 byte offset to initial data table 50 4 length of initial data table 54 4 length of optional header - additional information can be stored just after the application header. 58 n optional header - this information is ignored by the OS. Table 7.2: Application Header Format Magic Number The magic number marks the beginning of the app header. Internal Application Name Every application has a unique internal name. Note: This field must match the internal application name in the Flash header. The internal application names in the app header and Flash header are case sensitive and must be identical. TI-89 / TI-92 Plus Developer Guide Not for Distribution Beta Version January 26, 2001