Add .gitignore and README.md.

.gitignore

@@ -0,0 +1 @@
+*~

README.md

@@ -0,0 +1,44 @@
+# a2zip - Infocom ZIP release 3 interpreter for Apple II, partially reverse-engineered
+
+Original code copyright Infocom, Inc.
+Disassembly including labels and comments copyright 1984 Eric Smith <spacewar@gmail.com>
+
+z2zip development is hosted at the
+[a2zip Github repository](https://github.com/brouhaha/a2zip/).
+
+## Introduction
+
+Infocom games are written in ZIL and compiled to Z-code, which is
+interpreted on a ZIP interpreter. ZIP interpreters were written for
+many computers, including the Apple II. In 1984 I did reverse-engineered
+a substantial portion of the Apple II release 3 ZIP interpreter, as
+used by e.g. Zork 3 release 10 and release 15.
+
+At the time, the best 6502 assembler available to me was the Microsoft
+ALDS assembler, which ran on CP/M on the Apple II using a Microsoft
+Z80 Softcard. The assembly source code is thus written for that
+assembler, and will not without some changes assemble with any other
+assembler.
+
+To use ALDS, ensure that the source files use CR LF line endings (as
+used by MS-DOS) and have a control-Z character at the end. (CP/M doesn't
+have precise file lengths, so it uses a control-Z to denote end of file.)
+Copy the files to an Apple CP/M disk (or disk image).
+
+An single Apple II floppy isn't large enough to hold all of the files
+needed. If you have a larger drive (perhaps a hard disk) accessible to
+CP/M, you can use these commands:
+
+    m80 =zip/l/c/r
+    cref80 =zip
+    l80 zip,zip/n/e
+
+If you need to use multiple drives, the commands will have to be adjusted.
+For example, if you have tools and source code on drive A, scratch files
+on drive B, and final object code and listing files on drive C, you could
+use:
+
+    m80 zip,b:zip=zip/c
+    cref80 c:zip=b:zip
+    l80 zip,c:zip/n/e
+