S8000 ~~Oni'l'0R Prograf.l; Introduction; Monitor Program Debug Environment; Monitor Program - ZiLOG System 8000 User Manual

USER
19
Zilog
USER
SECTION 3
S8000 r-mNITOR PROGRAl-1
3.1
Introduction
The S8000 Monitor Program includes basic debugging commands,
I/O control, and interface software for use with a serial
interface to a remote computer system. Detailed interfacing
procedures are found in the S8000 Hardware Reference r·lanual
(03-3198) •
3.2 Monitor Program Debu~ Environment
The Moniter Program sets software breakpoints for program
debugging. A breakpoint is a command that interrupts or
stops program execution at a specified address in the pro-
gram. The address specified in the breakpoint is the
address of the instruction. When encountered during pro-
gram execution, the breakpoint suspends execution of the
user's program and saves all registers, program counters
(PC), and the flag control word (FCW) in the memory area
provided. It then displays a message reporting the break
and the address where it occurred. -
Any number of breakpoints can be set manually by setting the
desired breakpoint address to %7FOO (% indicates the address
is in hex notation). This interrupts the executing program
and jumps (traps) to the breakpoint procedure. The break-
point must be located at an even address. When the break-
point is no longer required, the original instruction must
be manually restored.
The BREAK command saves the address where the breakpoint is
being set and the instruction that it is replacing. When
the breakpoint is cleared, the instruction is automatically
restored. The BREAK command also stores a repetition
counter, n. Execution is not suspended until the nth time
this breakpoint is encountered unless another breakpoint is
encountered first.
The following restrictions on the user program are necessary
to set breakpoints:
1. The program must be able to execute with inter-
rupts enabled after encountering the breakpoint.
Zilog
19