C64-EMULATOR V2 --------------- "C64-EMULATOR2.SFX" is a self-extracting archive(execute it in C64-mode), which contains these files: C64-EMULATOR V2: C64-"emulation" for the Commodore 128 VIDEO-$CC00: Basic-program to change the locations of the video-ram, the charset and the basic-start C64-EMULATOR.TXT: This text(in PET-ASCII) TYPE TEXT: Program to view and print text-files What is the sense of a C64-emulation for the C128, when there is a built-in C64-mode? It gives you the possibility to port your C64-programs to the C128-mode with just a few changes, and use for example the second ram-bank or the second color ram, or you can write routines which use the burst mode of the serial bus. In contrast to the C64-mode all these things are still available when "C64-EMULATOR V2" is running. When you start the program(just "RUN" it), the charset is copied to $1000 and $9000, where in C64-mode the VIC always sees an image of the charset-ROM(in C128-mode there are images at $1000, $5000, $9000 and $D000, but only if bit 2 in $01 is low), and to $D000. After that a slightly changed version of the C64-operating system is installed and started via the reset-routine. The changes to the normal C64 are: 1.)In the memory-initialization-routine at $FD50 the RAM-test is skipped and the start of ROM is immediately set to $A000. 2.)The standard value for adress $01 at $FDD6 is changed from $E7 to $E3, which makes the ROM-Images of the charset available. 3.)Because $FF00-$FF04 is occupied by the MMU-configuration-register and the load-configuration-registers, the code normally found at this placed is moved to $FD71(formerly used by the RAM-test-routine) and a jump to it is installed at $FEFC. 4.)Finally the startup-text at $E473 is changed. Remember that you cannot use the "RAM below ROM"($A000-$BFFF and $E000-$FFFF) or change the memory setup via $01. Instead of that you have access to the MMU-registers at $D500 and $FF00. "VIDEO-$CC00" moves the video-RAM to $CC00 and allows you to change the beginning of basic-programs to $0801(C64-standard) or $0401(which gives you 1 KByte of extra-memory). It uses the charset at $D000. "C64-EMULATOR V2" is free software. It is distributed without any warranty. Thomas Klein, 15/04/98 E-Mail: thkle`stud.uni-sb.de ########################################################################