Re: ProDEV DDT debugger?

["josephoswaldgg@hotmail.com" <josephoswald@gmail.com>]

aiiadict@gmail.com wrote:

>
> last: hardware timer.  It mentions that Prodev will
> count number of cycles required to execute code
> between two addresses.  I don't understand why
> you would want this, it can be done in software.
> But, You have to detect start address on the
> bus.  count, synched with apple clock, detect
> end address on bus, stop the count.  The count
> has to be available on the bus.  Doesn't sound
> very hard to get done.

In general, this cannot be done accurately in software without a
real-time microsecond clock; the software has no idea if something
caused an interrupt or other activity that causes the execution flow to
change, or delays activity on the bus.

Also, things like "how many times does this loop execute" can depend on
specific events, such as when keys are pressed, or paddle settings, or
what characters show up on a serial line, what position a disk was in,
or whether your pacman eats a monster or not. A simple cycle count on
the assembler listing can't tell you what happened on a particular run.