g

Format

The format for the g command is:

g [-st] [adr [bptadr]] [-c args-]

where:

-s

is a flag indicating that the stack pointer, sp, should not be set.

-t

is a flag that causes the execution time of the client program to be displayed in seconds.

adr

is the address of the first instruction to be executed.

bptadr

is a breakpoint address where program execution is to be stopped. This breakpoint is removed the next time that execution halts.

-c args

indicates that the argument or arguments args are to be passed to the client program.

By default, the g command starts program execution at the address in the EPC register, and sets the stack pointer, sp, to the beginning of the stack area.

Functional Description

The g command starts program execution. If the user does not specify the starting address adr, execution starts at the current value of the EPC register. This command must only be used once after downloading a new program. Use the c command to continue execution after a breakpoint.

If the user specifies the -c option, the Monitor passes all arguments after -c to the client program by the following method. If -c is specified, the Monitor places the number of arguments (argc) in Register a0. The Monitor also places the address of an array of pointers to the command argument-strings in Register a1. The first element in the array pointed to by a1 contains a pointer to the string -c (the option on the command line). Note that if the -c is not specified, register a0 will be set to zero.

If adr is specified, a temporary breakpoint (bptadr) may also be specified. The temporary breakpoint remains in effect only until the next time that program execution is halted. The character '.' may be used as a placeholder for the adr if you wish to specifiy a temporary breakpoint without specifying a start address.

If you use the standard start-up file for executing programs under the control of the PROM Monitor, the function main will receive two incoming arguments, argc and argv, having the correct values to permit a program to read options from the command line, where argv[0] is a pointer to the string -c.

Note that a program built using version 4.0 of pmcc will not execute under pre-3.0 versions of the PROM Monitor unless the -c option is specified in the g command.

Examples illustrating the use of the g command follow.

PMON> g				Start executing at the current value of 
				the EPC register.

PMON> g a0020000		Start executing at 0xa0020000.

PMON> g a0020000 a0020008	Start executing at 0xa0020000 and 
				break at 0xa0020008.

Files

The g command is located in mon/go.c.

See Also

c command