The netboot command loads binary object files over Ethernet interface.
The format for this command is:
netboot [-bensy] [ host:[ path]]
where:
| -b | suppresses deletion of all breakpoints before the download. |
| -e | suppresses clearing of the exception handlers. |
| -n | suppresses the loading of symbols from the file. |
| -s | suppresses clearing of the symbol table before the download. |
| -y | loads only the symbols from the file. |
| host | is the internet host from which to read the file. |
| path | is the file name to be loaded from the host. |
Invoking the netboot command with no parameters or arguments clears the symbol table, deletes all current breakpoints, and attempts to load the program found in the host and file specified by the bootaddr and bootfile environment variables.
The netboot command uses the TFTP (Trivial File Transfer Protocol) to load an executable binary file from a remote host over Ethernet.
PMON/2000 can read files in ELF 32-Bit format as used in:
PMON/2000 extracts any symbol table information from these files, and adds it to the target symbol table, unless overriden on command line.
The netboot command normally clears the symbol table, exception handlers, and all breakpoints. The -s and -b options suppress the clearing of the symbol table and breakpoints, respectively. The value of the PC register is set automatically to the entry point of the program. Therefore, to execute the downloaded program, only the g command is required.
The boot command may return a large number of different error messages, relating to network problems or file access permissions on the remote host. For a file to be loaded via TFTP it must be publicly readable, and it may have to be in a directory which is acceptable to the remote server. See tftp section for more information about setting up and using TFTP.
When reading the symbol table PMON/2000 may complain that it does not have enough room to store the program’s symbols. To increase the size of the heap, use the set heaptop command to reserve more space and, if necessary, relink your program with a higher base address. The boot command will also detect cases where the program being loaded would overwrite PMON’s crucial data or heap: again relinking your program at a different address will cure the problem.
While it is loading each section of the file, boot displays the memory address (in hex) and size (in decimal) of that section. Typically these sections will be in the order .text, .data and .bss.
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