> When using the access bank you do not have to worry about
> banks at all. The ISR-temp regs should be in the access
> bank, of course.

Jan-Erik, I accept your comments. I was trying to illustrate to Josh
how the memory addressing works, and as such used some absolute
addressing

>> In effect BSR works like banksel,
> 
> ???
> Not "works like". BSR is a register and BANKSEL is a MPASM
> directive. BANKSEL simply sets the BSR bits

Well, I'd hair-split with that a little. 16F BANKSEL sets RP bits in
STATUS. 18F MOVLB sets bits in BSR. The intention is achieved
"in effect"

16F BANKSEL PORTA =>

BCF STATUS,0x5
BCF STATUS 0x6

18F BANKSEL LATA =>

MOVLB 0x0F

The thing is, if you happen to set the wrong bank on a 16F you could
be altering TRISA, which has the same relative address from the start
of the bank as PORTA does. That won't happen on the 18F

>> so you would use it to work with the RAM in a particular block.
>> There is not the ambiguity though of SFRs sharing addresses in
>> different banks
>>
>> eg (18F)
>>
>>           movlb   .1
>>           movlw   0x04
>>           movwf   lata
> 
> No.
> 
>    BANKSEL   LATA
>    MOVLW     0x04
>    MOVWF     LATA

Sorry, my fault. Without comments you didn't get what I meant. A
better example would be

If RAM location 0x004 holds 0x39, and RAM 0x104 holds 0x31

movlb .0 ;RAM block 0x000 - 0x0ff
movfw 0x104
movwf lata

LATA = 0x39

movlb .1 ;RAM block 0x100 - 0x1ff
movfw 0x104
movwf lata

LATA = 0x31

Not particularly elegant code, I appreciate that. In that example it does
show that banking is effected for getting to the source

> But, since LATA is in the access bank, that isn't needed. LATA
> can *always* be accessed no matter the current BSR setting

That was I intended to say, but my explanation fell short

>> 'banksel' the pseudo-op isn't applicable on the 18F.
> 
> Of course it is

I haven't used banksel very much at all on the 18F, and unfortunately
overlooked it. A terrible gaffe on my part

banksel source
movfw
banksel target
movwf

is a legitimate sequence

> SFRs don't co-exist with GPRs in a block like they do on a 16F,
> 
> Yes they do !

Well, I did mention an exception

> I'd seriously advice anyone interesting in the PIC18 to read up on
> the architecture themselfs

Agreed. 16F architecture has more differences than similarities when
compared with 18F, and I did make a bit of a dog's dinner trying to
show that ;-)

wbr
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