HP gnu source-level debugger 5992-4701 Setting breakpoints page 52. This form of the command

until, u	Continue running until a source line past the current line, in the
	current stack frame, is reached. This command is used to avoid
	single stepping through a loop more than once. It is like the
	next command, except that when until encounters a jump,
	it automatically continues execution until the program counter
	is greater than the address of the jump.
	This means that when you reach the end of a loop after single
	stepping though it, until makes your program continue
	execution until it exits the loop. In contrast, a next command
	at the end of a loop simply steps back to the beginning of the
	loop, which forces you to step through the next iteration.
	until always stops your program if it attempts to exit the
	current stack frame.
	until may produce somewhat counterintuitive results if the
	order of machine code does not match the order of the source
	lines. For example, in the following excerpt from a debugging
	session, the f (frame) command shows that execution is stopped
	at line 206; yet when we use until, we get to line 195:
	((gdb)) f
	#0 main (argc=4, argv=0xf7fffae8) at m4.c:206
	206 expand_input();
	((gdb)) until
	195 for ( ; argc > 0; NEXTARG) {
	This happened because, for execution efficiency, the compiler
	had generated code for the loop closure test at the end, rather
	than the start, of the loop―even though the test in a C for-loop
	is written before the body of the loop. The until command
	appeared to step back to the beginning of the loop when it
	advanced to this expression; however, it has not really gone to
	an earlier statement―not in terms of the actual machine code.
	until with no argument works by means of single instruction
	stepping, and hence is slower than until with an argument.
until location,	Continue running your program until either the specified
u location	location is reached, or the current stack frame returns. location
	is any of the forms of argument acceptable to break (see
	“Setting breakpoints” (page 52)). This form of the command
	uses breakpoints, and hence is quicker than until without an
	argument.

66 Stopping and Continuing