Intel 80L186EB Computer Hardware User Manual


 
INTEL 186 EB/EC EVALUATION BOARD USER’S MANUAL
5-8
GO FROM code_addr FOREVER
This command loads the user’s PC with code_addr, clears the
breakpoint array, and starts execution of the user’s code.
GO FROM code_addr TILL code_addr
This command loads the user’s PC with the code_addr that follows
the FROM keyword, sets the first breakpoint (BR[0]) to the
code_addr that follows the TILL keyword, and starts execution of
the user’s code.
GO FROM code_addr TILL code_addr OR code_addr
This command acts like the previous command, except that it also
sets the second breakpoint (BR[1]) to the code_addr that follows the
OR keyword.
GO TILL code_addr This command sets the first breakpoint (BR[0]) to code_addr and
starts the execution of user code using the current setting of the user’s
PC and the breakpoint array.
GO TILL code_addr OR code_addr
This command acts like the previous command, except that it also
sets the second breakpoint (BR[1]) to the code_addr that follows the
OR keyword.
HALT This command stops execution of user code by forcing the processor
to execute a jump to self instruction in a reserved location.
5.3.4 Program Stepping
These commands allow stepping through programs one instruction at a time. Between instruc-
tions, the iECM-86 commands can be used to check the state of the variables changed by the
instruction, to ensure that the program is operating properly. Stepping through code allows a more
detailed look at what is going on in the program. The price paid for this detail is that stepping does
not occur in real time; this makes it difficult, or perhaps impossible, to use on code that is tied to
real-time events.
Stepping while interrupts are enabled would be confusing, since interrupt service routines would
be stepped through as well as sequential code. iECM-86 avoids this problem by artificially
locking out interrupts while stepping, ignoring the state of the interrupt enable (IF) or interrupt
mask.