Thursday, August 10, 2017

Version 0.4 of CSpect

This is a new release of my CSpect emulator with yet more ZX Spectrum Next features.

You can now set sprite and screen order priorities, and the included Layer 2 scrolling demo+source shows how to do this.
Full memory banking has been added, so you can now use the full 1MB of RAM that will come with the next! (well....subject to change, and esxDOS pinching some). Again the Layer 2 demo shows this function in the utils.asm file. The comments also show the general layout of memory, so you should take a look there before using the paging.

Layer 2 double buffering! You can now have 2 Layer 2 buffers and page in either to $0000-$3ffff using the new bit layout in port $123b - see the included read me. for more details. To flip buffers, you just need to swap register 18 and register 19 values around.

There are also several new Z80 opcodes to play with! My included assembler will assemble these correctly for use in the emulator. There are a few more to come.....

   swapnib    ED 23    A bits 7-4 swap with A bits 3-0
   mul        ED 30    multiply HL*DE = HLDE (no flags set)
   add  hl,a  ED 31    Add A to HL (no flags set)
   add  de,a  ED 32    Add A to DE (no flags set)
   add  bc,a  ED 33    Add A to BC (no flags set)
   outinb     ED 90    out (c),(hl), hl++
   ldix       ED A4    As LDI,  but if byte==A does not copy
   ldirx      ED B4    As LDIR, but if byte==A does not copy
   lddx       ED AC    As LDD,  but if byte==A does not copy, and DE is incremented
   lddrx      ED BC    As LDDR,  but if byte==A does not copy

The file system will (should) also now accept '*' or '$' as setting the current drive. (untested)

I have also started to add some basic Audio, so the spectrum beeper now works.

Lastly.... the Sprite shape register has switched from port $55 to port $5B

Download: CSpect Emulator

1 comment:

Unknown said...

Where do these new Z80 opcodes come from? Are there a new set of undocumented comments?