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Found 3 results

  1. When programming in assembly language, quite often you will need to do calculations that would normally require floating point math. Those subroutines are available, the same ones that BASIC uses, but they are very slow. And if you're programming in assembly, you're doing so because it's much faster than BASIC, so using those routines can defeat the purpose, particularly if you need to do a lot of such calculations. Ideally in assembly language you want to have most of your variables consisting of single bytes, not the four used for floating point. It's having to move all those bytes around and doing calculations involving all of them that makes the floating point subroutines slow. And if you're going for speed, you can make a tradeoff: increased speed at the expense of accuracy. A function involving a single byte can just be a lookup table. Over the last several years I have developed a number of lookup tables and subroutines that enable some very fast math on the 6502 and now 65c02. Inspired by @svenvandevelde's question about ATAN2, I decided to compile many of them into a single 8kb file that can be loaded into banked RAM. I have other such routines and lookup tables, but I decided to just include those that would most likely be useful to the broadest range of applications. These lookup tables and functions will work on all revisions of the X16 emulator, and indeed will work on any 65c02 system as long as the file is loaded at $A000. The functions are all called through JMP redirects in page BF, and those JMP table locations will not change if I do revisions on the code. I'm pretty sure I killed all the bugs, but some might have slipped through. I'll be using further posts in this thread as sort of a user guide, but attached to this post is the file FASTMATH.BIN (the lookup tables and functions) and a text file containing the BASIC program that made all of the lookup tables (but don't copy and paste it into the emulator or it will overwrite FASTMATH.BIN). When using FASTMATH.BIN, you must use a relocated load to put it into banked RAM, otherwise it will load into memory at $7000 and won't work. Or you could load it into its default location at $7000 and just copy it up into the RAM bank of your choice. This software is released under an MIT license, meaning you can use it freely for any purpose, commercial or non-commercial, as long as you leave the MIT license in there (it's located at $BF7F). And please, these functions are all just approximations accurate to about 1%, so don't use the software for controlling a nuclear power plant or medical equipment. maketables.txt FASTMATH.BIN
  2. libX16 View File libX16 is a utility library for those using C with the CC65 toolchain for the Commander X16. Library documentation is available from the github page: https://github.com/CJLove/libX16. Currently it supports loading/saving files to banked RAM and VRAM, playing sound data for the YM2151, and providing a VERA header file with additional constant definitions beyond those provided by CC65. This is a beta v0.1.0 release of libX16 for the Commander X16 rom version r37 and CC65. The attached artifact includes the library header files and library file for linking. Alternatively the library can be referenced as a git submodule in a github repo via the .gitmodules file: [submodule "libX16"] path = libX16 url = https://github.com/CJLove/libX16 Submitter ChrisL Submitted 07/11/20 Category Dev Tools
  3. ChrisL

    libX16

    Version 0.1.0

    31 downloads

    libX16 is a utility library for those using C with the CC65 toolchain for the Commander X16. Library documentation is available from the github page: https://github.com/CJLove/libX16 This is a beta v0.1.0 release of libX16 for the Commander X16 rom version r37 and CC65. The attached artifact includes the library header files and library file for linking. Alternatively the library can be referenced as a git submodule in the .gitmodules file: [submodule "libX16"] path = libX16 url = https://github.com/CJLove/libX16
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