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, 64 insertions, 0 deletions

diff --git a/linux/tile/float-stack.mu b/linux/tile/float-stack.mu
new file mode 100644
index 00000000..146995e7
--- /dev/null
+++ b/linux/tile/float-stack.mu
@@ -0,0 +1,64 @@
+type float-stack {
+  data: (handle array float)
+  top: int
+}
+
+fn initialize-float-stack _self: (addr float-stack), n: int {
+  var self/esi: (addr float-stack) <- copy _self
+  var d/edi: (addr handle array float) <- get self, data
+  populate d, n
+  var top/eax: (addr int) <- get self, top
+  copy-to *top, 0
+}
+
+fn clear-float-stack _self: (addr float-stack) {
+  var self/esi: (addr float-stack) <- copy _self
+  var top/eax: (addr int) <- get self, top
+  copy-to *top, 0
+}
+
+fn push-float-stack _self: (addr float-stack), _val: float {
+  var self/esi: (addr float-stack) <- copy _self
+  var top-addr/ecx: (addr int) <- get self, top
+  var data-ah/edx: (addr handle array float) <- get self, data
+  var data/eax: (addr array float) <- lookup *data-ah
+  var top/edx: int <- copy *top-addr
+  var dest-addr/edx: (addr float) <- index data, top
+  var val/xmm0: float <- copy _val
+  copy-to *dest-addr, val
+  add-to *top-addr, 1
+}
+
+fn pop-float-stack _self: (addr float-stack) -> _/xmm0: float {
+  var self/esi: (addr float-stack) <- copy _self
+  var top-addr/ecx: (addr int) <- get self, top
+  {
+    compare *top-addr, 0
+    break-if->
+    var zero: float
+    return zero
+  }
+  subtract-from *top-addr, 1
+  var data-ah/edx: (addr handle array float) <- get self, data
+  var data/eax: (addr array float) <- lookup *data-ah
+  var top/edx: int <- copy *top-addr
+  var result-addr/eax: (addr float) <- index data, top
+  return *result-addr
+}
+
+fn float-stack-empty? _self: (addr float-stack) -> _/eax: boolean {
+  var self/esi: (addr float-stack) <- copy _self
+  var top-addr/eax: (addr int) <- get self, top
+  compare *top-addr, 0
+  {
+    break-if-!=
+    return 1/true
+  }
+  return 0/false
+}
+
+fn float-stack-length _self: (addr float-stack) -> _/eax: int {
+  var self/esi: (addr float-stack) <- copy _self
+  var top-addr/eax: (addr int) <- get self, top
+  return *top-addr
+}