Denial

Hi, Meryt, [...] it's really ground my gears all my life that there's no version [of Elite] for the VIC. I understand why. The bitmapping makes it next to impossible. [...] it is not quite clear to me what led you to that false assumption. The VIC-20 is very well capable of doing bitmapped graphics!...

[...] the value of X could not be higher than the fateful 255, [...] ... yet people have managed to work with the 65xx being an 8-bit CPU all the time. Please check out my VICMON primer thread for standard idioms to address into the screen. If it's just the matter of initialising the screen content...

Even though bigger memory expansions shift things around on the VIC-20 (notably, BASIC memory and text/colour RAM), the behaviour and position of I/O (VIC and VIA) remains unchanged. a 35K RAM expansion (which I think pages in the cart memory over the built-in SRAM unless anyone can say different) T...

This is a tip: To plot the cursor on position x,y on the screen: X position is on allocation 211 decimal and Y on 214. But it doesn't work because what is needed is a print HOME and a PRINT after POKE 214,Y-1. It took me hours to find out. I found the answer in Compute!'s Gazette of december 1983. ...

heaven6502 wrote:And which demo[s] use that bus trick?

Warning by viznut/pwp, for example.

what if I do racing the beam and set $9001 later so it compares more often to $9004? As I wrote: you can't restart [the display window] after it ended by writing a corresponding higher value into $9001 ... I was always wondering how 4mat did stuff (like in C64 terms) FLD like tricks in his VIC20 in...

Many of the new graphics modes pioneered by tokra and me routinely use the entire ZP, stack and OS workspace (i.e. $0000..$03FF) for graphics data. The only thing that necessitates the use of ZP are the two indirect-ZP address modes, and maybe the odd cycle saved with ZP (instead of ABS) operands. P...

No. The display window is only triggered once per frame (when $9004 compares equal to $9001), i.e. you can't restart it after it ended by writing a corresponding higher value into $9001. What you *can* do is filling part of the display window with characters in multicolour that use %01010101 (85 dec...

Especially unexpanded for extra charm. What's the point of advocating the use of an essential non-standard hardware extension and at the same time 'disallowing' the use of RAM expansions? No - it wouldn't add any 'extra charm' to me. It just places an unnecessary restriction on any related endeavou...

$2A $52 $FB - $FE I wouldn't be that sure about $2A and $52. Even though there are no direct ZP operand fields of instructions in the BASIC interpreter that point to these two addresses, these two addresses are part of temporary float values (actually their 5th byte) and might be referenced by indi...

heaven6502 wrote:what are the ZPs which are really free?

Just $FB..$FE, actually.

...

You find more details in this post of mine.

You probably mean this one: 10-Bit Oscillator Frequency Resolution

@JonBrawn: PM sent

MrSterlingBS wrote:the Demo [...]

... uses overlapping sprites to render filled vectors on the C64 which is a method that does not transfer at all to the VIC-20 (again, that method is nothing spectacularly new. The demo "Snapshot" already did so in 2010, see the part at 7:14).

http://www.quiss.org/boo/ "BRR" is nothing new and effectively is an 8-bit 'randomized' DDA . It is illusory to assume a line routine plots ~200000 pixels/second just because the 'deciding' part within it executes in 5 cycles. This is completely ignoring the other necessary parts of the r...