>     so in other words, the $ symbol really means 'the current line'
>     not the program counter ('cause the program counter is pointing
>     to the next instruction)
>
> Note that this is assembler and sometimes CPU architecture dependent.
> (not that I can think of an assembler where "jump $" is a no-op, or
> a CPU that increments the PC at the end of the instruction, but I'm
> pretty sure I've seen at least one of those somewhere...)

I don't know if I've seen any assemblers where "[jump-operation] $" is a NOP
though I have seen some where "jmp *" is a nop; one 6502 assembler I used
would interpret the "*" as (address of next instruction) and "$" as (address
of current instruction).  I think I also once used a Z80 one that was just
the opposite.

There are arguments to be had for both; a "GOTO $" of one for is a spin
forever or until interrupt; a "GOTO $" of the other form would be a two
cycle nop.  Both are potentially useful, especially on assemblers which
may produce more than one word of code per line (e.g. if the assembler
has a "jnz" instruction, where should the '$' point?).  Of course, a good
local-labeling facility can pretty much obviate the need for such things,
but one has to use what one has [ducking before someone throws the "$ is
the one true form of hex" back in my face].

One particularly nice assembler I used (forget which one) could accomodate
local labels as follows (writing from memory): a label whose definition
started with "@" would be a local label; the assembler would keep a counter
of how many times each such label had been used and adjust the name by
prepending a number (so the first use of "@foo" would turn into "0001@foo",
the second into "0002@foo", etc.  When referencing such a label, one would
attach a special prefix to indicate whether one wanted the NEXT such label
in the code or the PREVIOUS one.  So, for example [pretending this assembler
was for the PIC] the code

        movlw   8
        movwf   Count
@loop:
        decfsz  Count
         goto   b@loop  ; b@ as a prefix means to look "back"
        decf    Count2
        btfss   Z
         goto   f@done
        movlw   99
        movwf   Count2
@done:

might get translated as [depending upon how many other places had "@loop"
and "@done" defined]

        movlw   8
        movwf   Count
@0034loop:
        decfsz  Count
         goto   b@0034loop
        decf    Count2
        btfss   Z
         goto   f0019@done
        movlw   99
        movwf   Count2
@0019done:

This facility was much less chancy than using the "$+whatever" format, but
is probably simpler for the compiler than traditional local labels.  It's
also much more versatile, since it can work with cut and pasted code as
well as with macros.  Of course, one has to be careful that one's desired
targets actually exist as expected; if not wierd things may happen.  Still,
it's a neat approach and one I'd like to see used more often.