emul: update README

emul/README.md

@@ -8,16 +8,6 @@ emulator.
 You need `ncurses` to build the `forth` executable. In debian-based distros,
 it's `libncurses5-dev`.
 
-## Not real hardware
-
-In the few emulated apps described below, we don't try to emulate real hardware
-because the goal here is to facilitate "high level" development.
-
-These apps run on imaginary hardware and use many cheats to simplify I/Os.
-
-For real hardware emulation (which helps developing drivers), see the `hw`
-folder.
-
 ## Build
 
 First, make sure that the `libz80` git submodule is checked out. If not, run
@@ -27,34 +17,18 @@ After that, you can run `make` and it builds the `forth` interpreter.
 
 ## Usage
 
-Run `./forth` to get the Collapse OS prompt. Type `0 LIST` for help.
+The `./forth` executable here works like the one in `/cvm`, except that it runs
+under an emulated z80 machine instead of running natively. Refer to
+`/cvm/README.md` for details.
 
-The program is a curses interface with a limited, fixed size so that it can
-provide a AT-XY interface.
-
-You can get a REPL by launching the program with [`rlwrap(1)`][rlwrap] like
-this:
-
-    rlwrap -e '' -m -S '> ' ./forth /dev/stdin
-
-## Problems?
-
-If the `forth` executable works badly (hangs, spew garbage, etc.),
-it's probably because you've broken your bootstrap binaries. They're easy to
-mistakenly break. To verify if you've done that, look at your git status. If
-`forth.bin` is modified, try resetting it and then run `make clean all`. Things
-should go better afterwards.
+## Not real hardware
 
-A modified `blkfs` can also break things (although even with a completely broken
-blkfs, you should still get to prompt), you might want to run `make pack` to
-ensure that the `blkfs` file is in sync with the contents of the `blk/` folder.
+`./forth` doesn't try to emulate real hardware
+because the goal here is to facilitate "high level" development.
 
-If that doesn't work, there's also the nuclear option of `git reset --hard`
-and `git clean -fxd`.
+These apps run on imaginary hardware and use many cheats to simplify I/Os.
 
-If that still doesn't work, it might be because the current commit you're on
-is broken, but that is rather rare: the repo on Github is plugged on Travis
-and it checks that everything is smooth.
+For real hardware emulation (which helps developing drivers), see the `hw`
+folder.
 
 [libz80]: https://github.com/ggambetta/libz80
-[rlwrap]: https://linux.die.net/man/1/rlwrap