Commander X16

This was a common problem even back in the 90s with VGA DOS games, the border was picking up whatever color the first index of the palette was using, but VERA has this awesome register that can set which palette index to use for the border: BORDER_PAL_INDEX = 0 ; Use any number between 0-255, select...

You're welcome! :D Do I need to set bit 6 (accumulate) in $9F2C DCSEL=2 on initialization? I don't think I am, since things are working. You don't need to, because writing a "1" to bit 6 in $9F2C[DCSEL=2] does the exact same thing as reading $9F2A[DCSEL=6], you just use whichever one is c...

I found a couple errors in your code: It never actually touches Multiplier_Enable ($9F2C.4, DCSEL=2). It mistakenly reads from $9F25 instead of $9F29 when trying to reset the accumulator, although it sets DCSEL correctly right beforehand. It mistakenly writes to $9F25 instead of $9F29 when trying t...

Slight change of subject but does the emulator "emulate" vsync? Because I've not used the proper hardware and have never had any issues with vblank timing like screen tearing etc. Yes, it is emulated. Even if you haven't had any issues, it is recommended to always be prepared for screen t...

Thank you Wavicle and DragWx! I now got a functional dot product subroutine that takes two vectors in 1.7.8 fixed point format, and returns a scalar as a 1.7.8 fixed point, not including the call overhead or setting the values, takes 161 cycles: ZP_MUL_X0 = $22 ; Zero Page ZP_MUL_X1 = $24 ZP_MUL_Y0 ...

; Initialize LDX #$1F LDY #$61 STZ $9F25; for ADDRSEL ; =8 cycles next: ; Set DATA0 address, set increment to +32. STY $9F22 LDA #$FC STA $9F21 STX $9F20 ; =14 Cycles ; 32 pairs of LDA/STA, with 32-byte offset. LDA SpriteTable,X STA $9F23 LDA SpriteTable+$20,X STA $9F23 LDA SpriteTable+$40,X STA $9...

So far I can only multiply two 16-bit values by setting the 32-bit cache directly, and then having VERA write the result to VRAM for me to fetch using the CPU. The official documentation talks about the "accumulator" as some form of reset operation. I need addition of two multiplication re...

The same documentation says: SCANLINE.... this value continues to count beyond the last visible line, but returns $1FF for lines 512-524 that are beyond its 9-bit resolution . Note that VERA renders lines ahead of scanout such that line 1 is being rendered while line 0 is being scanned out. Visible ...

You won't be changing ALL sprite attributes every frame I would think? First off, thank you for the test program! I am very used to programming on the Sega Genesis and Nintendo DS, where you keep a local copy in RAM of all the sprites and palette, and then just copy them to OAM or VRAM with DMA dur...

I have been programming the Commander X16 for a while now, and it feels odd that it doesn't have a way to upload a full palette and all the sprites to VRAM like most game consoles of the past did thanks to DMA. The issue is, there are 256 palette entries (which is 512 bytes, so two loops basically) ...