Indirect register access in examine/deposit commands ... possible?

[AK6DN]

In debugging some code on the PDP11, I have a need to examine memory at a variable location, whose address is in a register (ie, like SP).

Ideally I'd like to do something like: EX (SP) or even EX 4(SP)-12(SP)

Is there a way to do this using existing command syntax? I can't find any way.

Or would this be classified as a new feature?

I just started using the RWSX breakpoint feature (very nice!) but now need the above functionality.

[markpizz]

There currently is minimal (no) expression evaluation functionality.
However, there is:

sim> ; Display some register value
sim> EX SP
sim> ; Use the last displayed value as an address to examine now
sim> EX $

The $ (last value referenced) was added a while back but hasn't seen much use or your request would have come up earlier.

So, I've just added the extended the allowed syntax to now allow:

sim> ; Use the last displayed value as an address to examine now
sim> EX $/10

Which will use the last value displayed as the starting address and display that address thru N-1 beyond it (where in this example N is 10).

Additionally, you can combine both of these in a breakpoint action string:

sim> bre 100 ; ex sp ; ex $/12
sim> dep pc 100
sim> g

Breakpoint, PC: 000100 (HALT)
sim> ex sp
SP: 000000
sim> ex $/12
0: 000000
2: 000000
4: 000000
6: 000000
10: 000000
sim>

[AK6DN]

Thanks for the pointer, that seems to work. I tried this:

set break -sx 17777172 ; ex r0,$,r1,$,r2,$,r3,$,r4,$,r5,$,sp,$ ; cont

and it does what you might expect, where $ equates to the last value examined.

I don't need the length option just yet, I'll get that when I pull the next commit.

Thanks for the help!
Don