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, 135 insertions, 0 deletions

diff --git a/linux/raytracing/vec.mu b/linux/raytracing/vec.mu
new file mode 100644
index 00000000..7caf7e88
--- /dev/null
+++ b/linux/raytracing/vec.mu
@@ -0,0 +1,135 @@
+type vec3 {
+  x: float
+  y: float
+  z: float
+}
+
+fn print-vec3 screen: (addr screen), _v: (addr vec3) {
+  var v/esi: (addr vec3) <- copy _v
+  print-string screen, "("
+  var tmp/eax: (addr float) <- get v, x
+  print-float-hex screen, *tmp
+  print-string screen, ", "
+  tmp <- get v, y
+  print-float-hex screen, *tmp
+  print-string screen, ", "
+  tmp <- get v, z
+  print-float-hex screen, *tmp
+  print-string screen, ")"
+}
+
+fn vec3-add-to _v1: (addr vec3), _v2: (addr vec3) {
+  var v1/edi: (addr vec3) <- copy _v1
+  var v2/esi: (addr vec3) <- copy _v2
+  # v1.x += v2.x
+  var arg1/eax: (addr float) <- get v1, x
+  var arg2/ecx: (addr float) <- get v2, x
+  var result/xmm0: float <- copy *arg1
+  result <- add *arg2
+  copy-to *arg1, result
+  # v1.y += v2.y
+  arg1 <- get v1, y
+  arg2 <- get v2, y
+  result <- copy *arg1
+  result <- add *arg2
+  copy-to *arg1, result
+  # v1.z += v2.z
+  arg1 <- get v1, z
+  arg2 <- get v2, z
+  result <- copy *arg1
+  result <- add *arg2
+  copy-to *arg1, result
+}
+
+fn vec3-subtract-from v1: (addr vec3), v2: (addr vec3) {
+  var tmp-storage: vec3
+  var tmp/eax: (addr vec3) <- address tmp-storage
+  copy-object v2, tmp
+  vec3-negate tmp
+  vec3-add-to v1, tmp
+}
+
+fn vec3-negate v: (addr vec3) {
+  var negative-one/eax: int <- copy -1
+  var negative-one-f/xmm0: float <- convert negative-one
+  vec3-scale-up v, negative-one-f
+}
+
+fn vec3-scale-up _v: (addr vec3), f: float {
+  var v/edi: (addr vec3) <- copy _v
+  # v.x *= f
+  var dest/eax: (addr float) <- get v, x
+  var result/xmm0: float <- copy *dest
+  result <- multiply f
+  copy-to *dest, result
+  # v.y *= f
+  dest <- get v, y
+  result <- copy *dest
+  result <- multiply f
+  copy-to *dest, result
+  # v.z *= f
+  dest <- get v, z
+  result <- copy *dest
+  result <- multiply f
+  copy-to *dest, result
+}
+
+fn vec3-scale-down _v: (addr vec3), f: float {
+  var v/edi: (addr vec3) <- copy _v
+  # v.x /= f
+  var dest/eax: (addr float) <- get v, x
+  var result/xmm0: float <- copy *dest
+  result <- divide f
+  copy-to *dest, result
+  # v.y /= f
+  dest <- get v, y
+  result <- copy *dest
+  result <- divide f
+  copy-to *dest, result
+  # v.z /= f
+  dest <- get v, z
+  result <- copy *dest
+  result <- divide f
+  copy-to *dest, result
+}
+
+fn vec3-unit in: (addr vec3), out: (addr vec3) {
+  var len/xmm0: float <- vec3-length in
+#?   print-string 0, "len: "
+#?   print-float-hex 0, len
+#?   print-string 0, "\n"
+  copy-object in, out
+  vec3-scale-down out, len
+}
+
+fn vec3-length v: (addr vec3) -> _/xmm0: float {
+  var result/xmm0: float <- vec3-length-squared v
+  result <- square-root result
+  return result
+}
+
+fn vec3-length-squared _v: (addr vec3) -> _/xmm0: float {
+  var v/esi: (addr vec3) <- copy _v
+  # result = v.x * v.x
+  var src/eax: (addr float) <- get v, x
+  var tmp/xmm1: float <- copy *src
+  tmp <- multiply tmp
+  var result/xmm0: float <- copy tmp
+  # result += v.y * v.y
+  src <- get v, y
+  tmp <- copy *src
+  tmp <- multiply tmp
+  result <- add tmp
+  # result += v.z * v.z
+  src <- get v, z
+  tmp <- copy *src
+  tmp <- multiply tmp
+  result <- add tmp
+  return result
+}
+
+fn vec3-dot _v1: (addr vec3), _v2: (addr vec3) -> _/xmm0: float {
+}
+
+fn vec3-cross _v1: (addr vec3), _v2: (addr vec3), out: (addr vec3) {
+}