How to use SIS with GDB ----------------------- 1. Building GDB with SIS To build GDB with the SIS/ERC32 simulator, configure with option '--target sparc-erc32-aout' and build as usual. 2. Attaching the simulator To attach GDB to the simulator, use: target sim [options] [files] The following options are supported: -nfp Disable FPU. FPops will cause an FPU disabled trap. -freq Set the simulated "system clock" to MHz. -v Verbose mode. -nogdb Disable GDB breakpoint handling (see below) The listed [files] are expected to be in aout format and will be loaded in the simulator memory prior. This could be used to load a boot block at address 0x0 if the application is linked to run from RAM (0x2000000). To start debugging a program type 'load ' and debug as usual. The native simulator commands can be reached using the GDB 'sim' command: sim Direct simulator commands during a GDB session must be issued with care not to disturb GDB's operation ... For info on supported ERC32 functionality, see README.sis. 3. Loading aout files The GDB load command loads an aout file into the simulator memory with the data section starting directly after the text section regardless of wich start address was specified for the data at link time! This means that your applications either has to include a routine that initialise the data segment at the proper address or link with the data placed directly after the text section. A copying routine is fairly simple, just copy all data between _etext and _data to a memory loaction starting at _environ. This should be done at the same time as the bss is cleared (in srt0.s). 4. GDB breakpoint handling GDB inserts breakpoint in the form of the 'ta 1' instruction. The GDB-integrated simulator will therefore recognize the breakpoint instruction and return control to GDB. If the application uses 'ta 1', the breakpoint detection can be disabled with the -nogdb switch. In this case however, GDB breakpoints will not work. Report problems to Jiri Gaisler ESA/ESTEC (jgais@wd.estec.esa.nl)