User guide

1.1. A CINTSYS CONSOLE SESSION 5
This first loads the entry point of clihook (held in global va r ia b l e 4) and sets
(b1) a breakpoint numbered 1 at this position. The command b, without an
argument, lists the current breakpoints confirming that the correct one has been
set. Normal execution is continued using the c command.
* c
0.010>
If we n ow try to execute the factorial program, we immed i at e ly hit the break-
point.
0> fact
!! BPT 1: clihook
A= 0 B= 0 17940: K4G 1
*
This indicates that the breakpoint occurred when the Cintcode registers A and
B were bo th zero, and that the program counter is set to 17940 where the n ext
instruction to be obeyed is K4G 1. Single st ep exection can now be pe rfo r m ed
using the \ command.
* \ A= 0 B= 0 46276: L1
* \ A= 1 B= 0 46277: SP3
* \ A= 1 B= 0 46278: LP3
*
After each single step execution a summa r y of the cu r r ent state is printed. In the
above sequence we see that the execution of the instruction L1 loading 1 into the
A regist er . The execution of SP3 does not have an immediately observabl e effect
since it updates a l ocal va ri a b l e held in the current stack frame, but the stack
frame can be displayed using the t command.
* p t4
P 0: 46420 17942 start 1
*
This confirms that lo ca ti o n P3 contains th e va lue 1 corresponding to the initial
value of the for-loop control variable i. At this stage it is possible to change its
value t o 3, say.
* 3 sp3
* p t4
P 0: 46420 17942 start 3
*
If single stepping is continued for a while we ob se rve the evaluation of the
recursive call fact(3).