7842 - new directory organization

Baremetal is now the default build target and therefore has its sources
at the top-level. Baremetal programs build using the phase-2 Mu toolchain
that requires a Linux kernel. This phase-2 codebase which used to be at
the top-level is now under the linux/ directory. Finally, the phase-2 toolchain,
while self-hosting, has a way to bootstrap from a C implementation, which
is now stored in linux/bootstrap. The bootstrap C implementation uses some
literate programming tools that are now in linux/bootstrap/tools.

So the whole thing has gotten inverted. Each directory should build one
artifact and include the main sources (along with standard library). Tools
used for building it are relegated to sub-directories, even though those
tools are often useful in their own right, and have had lots of interesting
programs written using them.

A couple of things have gotten dropped in this process:
  - I had old ways to run on just a Linux kernel, or with a Soso kernel.
    No more.
  - I had some old tooling for running a single test at the cursor. I haven't
    used that lately. Maybe I'll bring it back one day.

The reorg isn't done yet. Still to do:
  - redo documentation everywhere. All the README files, all other markdown,
    particularly vocabulary.md.
  - clean up how-to-run comments at the start of programs everywhere
  - rethink what to do with the html/ directory. Do we even want to keep
    supporting it?

In spite of these shortcomings, all the scripts at the top-level, linux/
and linux/bootstrap are working. The names of the scripts also feel reasonable.
This is a good milestone to take stock at.

1 files changed, 133 insertions, 0 deletions

diff --git a/linux/tile/main.mu b/linux/tile/main.mu
new file mode 100644
index 00000000..e0daaf1b
--- /dev/null
+++ b/linux/tile/main.mu
@@ -0,0 +1,133 @@
+fn main args-on-stack: (addr array addr array byte) -> _/ebx: int {
+  var args/eax: (addr array addr array byte) <- copy args-on-stack
+  var len/ecx: int <- length args
+  compare len, 2
+  {
+    break-if-!=
+    # if single arg is 'test', run tests
+    var tmp/ecx: (addr addr array byte) <- index args, 1
+    var tmp2/eax: boolean <- string-equal? *tmp, "test"
+    compare tmp2, 0/false
+    {
+      break-if-=
+      run-tests
+      return 0  # TODO: get at Num-test-failures somehow
+    }
+    # if single arg is 'screen', run in full-screen mode
+    tmp2 <- string-equal? *tmp, "screen"
+    compare tmp2, 0/false
+    {
+      break-if-=
+      interactive
+      return 0
+    }
+    # if single arg is 'type', run in typewriter mode
+    tmp2 <- string-equal? *tmp, "type"
+    compare tmp2, 0/false
+    {
+      break-if-=
+      repl
+      return 0
+    }
+    # if single arg is 'test' ...
+    tmp2 <- string-equal? *tmp, "test2"
+    compare tmp2, 0/false
+    {
+      break-if-=
+      test
+      return 0
+    }
+  }
+  # otherwise error message
+  print-string-to-real-screen "usage:\n"
+  print-string-to-real-screen "  to run tests: tile test\n"
+  print-string-to-real-screen "  full-screen mode: tile screen\n"
+  print-string-to-real-screen "  regular REPL: tile type\n"
+  return 1
+}
+
+fn interactive {
+  enable-screen-grid-mode
+  enable-keyboard-immediate-mode
+  var env-storage: environment
+  var env/esi: (addr environment) <- address env-storage
+  initialize-environment env
+  {
+    render env
+    var key/eax: grapheme <- read-key-from-real-keyboard
+    compare key, 0x11/ctrl-q
+    break-if-=
+    process env, key
+    loop
+  }
+  enable-keyboard-type-mode
+  enable-screen-type-mode
+}
+
+fn test {
+  var env-storage: environment
+  var env/esi: (addr environment) <- address env-storage
+  initialize-environment-with-fake-screen env, 0x20, 0xa0
+  render env
+}
+
+fn process-all env: (addr environment), cmds: (addr array byte) {
+  var cmds-stream: (stream byte 0x100)
+  var cmds-stream-a/esi: (addr stream byte) <- address cmds-stream
+  write cmds-stream-a, cmds
+  {
+    var done?/eax: boolean <- stream-empty? cmds-stream-a
+    compare done?, 0/false
+    break-if-!=
+    var g/eax: grapheme <- read-grapheme cmds-stream-a
+    process env, g
+    loop
+  }
+}
+
+fn repl {
+  {
+    # prompt
+    print-string-to-real-screen "> "
+    # read
+    var line-storage: (stream byte 0x100)
+    var line/ecx: (addr stream byte) <- address line-storage
+    clear-stream line
+    read-line-from-real-keyboard line
+    var done?/eax: boolean <- stream-empty? line
+    compare done?, 0/false
+    break-if-!=
+    # parse
+    var env-storage: environment
+    var env/esi: (addr environment) <- address env-storage
+    initialize-environment env
+    {
+      var done?/eax: boolean <- stream-empty? line
+      compare done?, 0/false
+      break-if-!=
+      var g/eax: grapheme <- read-grapheme line
+      process env, g
+      loop
+    }
+    # eval
+    var stack-storage: value-stack
+    var stack/edi: (addr value-stack) <- address stack-storage
+    initialize-value-stack stack, 0x10
+    evaluate-environment env, stack
+    # print
+    var empty?/eax: boolean <- value-stack-empty? stack
+    {
+      compare empty?, 0/false
+      break-if-!=
+      var result/xmm0: float <- pop-number-from-value-stack stack
+      print-float-decimal-approximate 0, result, 3
+      print-string 0, "\n"
+      print-string 0, "width: "
+      var width/eax: int <- float-size result, 3
+      print-int32-decimal 0, width
+      print-string 0, "\n"
+    }
+    #
+    loop
+  }
+}