il65- intermediate level 6502 language


<crlf> := #13, #10
<commentchar> := #00..09, #11, #12, #14..#255
<anychar> := #00..#124, #126..#255
<digit> := '0'..'9'
<hexdigit> := '0'..'9', 'A'..'F', 'a'..'f'
<bindigit> := '0', '1'
<stringchar> := #32..#255
<alpha> := 'A'..'Z', 'a'..'z ...

thats how modern pascal deals with this in strings... with negative indices (for size and ref counting).

My idea of memory allocator is like a FAT table in a file system.

Have a small block of memory be a bitmap where bit = 1 equals allocated and bit = 0 is free.

On malloc, find the first block that fits the size asked by the application, mark every part with bit 1, and return a point to the first ...

VGA output from 3xVS23S010 (one for each color) :

http://forum.6502.org/images/migrated/052403-000.jpg

http://www.vsdsp-forum.com/phpbb/viewtopic.php?t=1798

Each VS23S010D-L costs US$6 in low volume (US$1.93 in kilo quantities). Thats US$18 for a video card with SPI bus interface.

I believe ...

OK, I've got a single dip with 32k of RAM on it. But that wasn't available back on the early eighties, and the RAM was spread over many chips.

Did those chips work just like the modern ones, but just have less address lines? So instead of the simple decode we do to select the entirety of RAM on ...

Now and then 3d memory modules appears in the market. I believe those would have a floor access strobe to select a chip among others...

I know that DRAM was cheaper than SRAM (1 transitor vs 6 for sram). But I am not talking about this. RAS/CAS allows, for example, to have 8 bits address pins, because you can do :
put 8 bits row in the bus.
strobe RAS
put 8 bits column in the bus.
strobe CAS.
8+8 = 16 bits, so you can address 64kb ...

In the 6502 era there was no cas/ras scheme, this is post a 1990 thing, mainly from PC world (SDRAM).

Edit:

Answer below tells me that RAS/CAS was indeed used during this time...

Whats the porpuse of it ?

I tought RAS/CAS was an addressing scheme to decrease the ever increasing number of address ...

The nice part is if you do it right, you'll be able to contrast the performance between inlining everything, and deferring some of it, perhaps down to simply using an interpreter for the whole shebang.

I am in the process of writing a preprocessor/scanner for pascal.

Almost done. I've added a ...

Hi Jim.
Until now, I have not had a chance to get acquainted with the products of Ohio Scientific. Everyone in his life had their own toys. I do not think that you can once again get the same pleasure from that old stuff as in those nice days. The 'first time' is possible only once. Nevertheless ...

Something tells me that this will work very slowly. Even to display and scroll alphanumeric data, 6502 should have to rewrite more than 100 kbyte of graphical buffer. Is not it?

If you are talking about the vs23s010, it has a internal blitter to accelerate things, and the lines shown in the ...

Never tried it, but, a solution that seems simple and cheap is the VS23S010-L from VLSI Solution.

http://www.vlsi.fi/en/products/vs23s010.html

128k byte sram plus video generator, via SPI.

Only does composite, but I believe you an use three chips to get VGA (theoretically possible).

I wrote several simple compilers in the past (ask me if you want to see some) and experience tells me that there is a certain set of common "subroutines" - repeated tasks - that map high level language constructs into assembly language programs - that if represented into a intermediate level ...