AB> Alright, obviously I should have read a bit further... "zero" refers to
AB> a memory location, but I still don't know what the #> thing does.
The <zero and >zero indicate to take the lower- and upper- half of the
address. The # in front indicates to use the immediate addressing
mode.
As an example, say that the label zero points to address $1234. The
'>zero' operation would return the value $12, and '<zero' would return
>$34. The operators return the high byte and low byte of a memory
address.
The reason for the # sign is so that the value is loaded into the
accumulator, as opposed to the contents of the memory location
indicated. That is, we want (from previous example) the value $12 in
the accumulator, and not the contents of memory location $12.
There is an easier-to-read mnemonic for this operation which escapes
me completely. It is part of the new DASM compiler or the new
vcs.h header file. I'm just used to using the > and < symbols.
I've probably made this more confusing than necessary; if you're still
confused someone may do a better job of explanation.
>> I'm looking through Robin Harbron's 6-digit routine and I've come
>> across some code I don't understand.
>>
>> asl
>>
>> adc #<zero
>> sta ptr0,y
>> lda #0
>> adc #>zero
>> sta ptr0+1,y
>>
>> What do the arguments "#<zero" and "#>zero" actually mean? The two
>> books, I have don't say anything about it, and the dig's search engine
>> won't let me do a search on the greater than symbol. I guess it seems
>> to assemble... does this just tell the assembler to use any number
>> greater or less than zero?
----------------------------------------------------------------------------------------------
Archives (includes files) at http://www.biglist.com/lists/stella/archives/
Unsub & more at http://www.biglist.com/lists/stella/
