As of Petal 1.0, the Petal compiler will only support amd64 on Linux.
Petal aims to support desktop computers for GUI and command line applications. The overwhelming majority of desktop computers use amd64. Windows and OSX both cost money.
One issue here is that strings in JS are UTF-16. We might want to create a type that makes it efficient to manage them. We might also need to ensure our template system can make it easier to handle various types of strings. Alternatively, we could make our existing string type support both UTF-8 and UTF-16. (How hard would that be?)
Future targets include Windows, AArch64, and MIPS. The primary development environment for Petal on Windows will likely be WINE. OSX will only be supported with donations.