2 files changed, 90 insertions, 0 deletions
diff --git a/problems/13-Mod-3/08.vsm b/problems/13-Mod-3/08.vsm
index 04838b2..6d9783d 100644
--- a/problems/13-Mod-3/08.vsm
+++ b/problems/13-Mod-3/08.vsm
@@ -1,3 +1,37 @@
+# (32 / 8).times do |i|
+#   j = i * 8
+#   # itof (1)
+#   puts "ior $lm#{j}v $lr0 $nowrite"
+# end
+# puts
+# (32 / 8).times do |i|
+#   j = i * 8
+#   # itof (2)
+#   puts "fvadd $aluf -$lr0 $ls#{j}v"
+# end
+# puts
+# (32 / 8).times do |i|
+#   j = i * 8
+#   # /3
+#   puts "fvmul $ls#{j}v $lr4 $nowrite"
+# end
+# puts
+# (32 / 8).times do |i|
+#   j = i * 8
+#   # ftoi
+#   puts "fftoi $mauf $ls#{j+32}v"
+# end
+# puts
+# (32 / 8).times do |i|
+#   j = i * 8
+#   # x3
+#   puts "ipackbit $ls#{j+32}v $lr8 $nowrite"
+#   puts "iadd $ls#{j+32}v $aluf $nowrite"
+#   # %3
+#   puts "isub $lm#{j}v $aluf $ln#{j}v"
+#   puts
+# end
+
 imm f"8388608" $r0v
 imm f"0.3333333333333333333333" $r4v
 
diff --git a/problems/13-Mod-3/a.rb b/problems/13-Mod-3/a.rb
new file mode 100644
index 0000000..b0e909b
--- /dev/null
+++ b/problems/13-Mod-3/a.rb
@@ -0,0 +1,56 @@
+def f1(n)
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+def f2(n)
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      ((n >> 6) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+def f3(n)
+  n = ((n >> 0) & 0b1111) +
+      ((n >> 4) & 0b1111) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      ((n >> 4) & 0b11) +
+      0
+  n = ((n >> 0) & 0b11) +
+      ((n >> 2) & 0b11) +
+      0
+  n == 3 ? 0 : n
+end
+
+256.times do |n|
+  expected = n % 3
+  actual = f3(n)
+
+  if actual != expected
+    puts "#{actual} != #{expected} (#{n}; #{"%08b" % n})"
+  end
+end