DS用DOS模拟器DSx86 v0.21 Beta

DS上的DOS模拟器，新版更新如下：
Version 0.21 info

This is mostly a fix version after the somewhat buggy version 0.20. This version includes the finished AdLib emulation, and I fixed the problem introduced in 0.20 with the Direct SB mode where the start of the BIOS F000 segment was overwritten with corrupt data. This version also has a lot more of the opcodes refactored to use the new more robust memory handling, which also means that this version will run slower than the previous version. Norton SysInfo tells that this version runs at 9.9 times original PC, while the version before any of these internal changes ran at 11.5 times original PC. I am still not even half way done with the internal refactoring, so the next version might still be slower, until I get all the refactoring done and can again start optimizing things.