Started a DEVELOPERS file

DEVELOPERS.md

@@ -0,0 +1,26 @@
+Notice: The kernel is still in early development. Some information in this file
+may be inaccurate. Please create an issue if this is the case.
+
+# Porting
+
+The kernel should be portable to most systems, provided they support paging
+and have sufficient memory. All platform-specific code belongs in an appropriately-named
+subdirectory inside src/. It must provide a linker script, startup code, and
+implement a set of functions required by the kernel.
+
+The linker script must define the following symbols:
+- _pageMapLocation      The location of the bitmap to be used by the page allocator.
+- _heapLocation         The location of the kernel's heap.
+- _heapSize             The size in bytes of the kernel's heap.
+- _kernelStart          The linear address of the start of the kernel image.
+- _kernelEnd            The first linear address after the end of the kernel image.
+
+The startup code is required to enable paging and relocate the kernel if necessary. It also
+needs to provide a memory map to the kernel in the form of an array of MemoryMap::Region
+structures. It should then call main() with a pointer to the kernel command line as an argument.
+
+In addition, the contents of mmap.hpp and interrupts.hpp must be implemented.
+
+# Files
+
+[TODO]