1 files changed, 114 insertions, 0 deletions
diff --git a/cpp/023jump b/cpp/023jump
new file mode 100644
index 00000000..669c7258
--- /dev/null
+++ b/cpp/023jump
@@ -0,0 +1,114 @@
+:(before "End Primitive Recipe Declarations")
+// Jump ops.
+JUMP,
+:(before "End Primitive Recipe Numbers")
+Recipe_number["jump"] = JUMP;
+:(before "End Primitive Recipe Implementations")
+case JUMP: {
+  trace("run") << "ingredient 0 is " << instructions[pc].ingredients[0].value;
+  pc += instructions[pc].ingredients[0].value;
+  trace("run") << "pc now " << pc;
+  break;
+}
+
+:(scenario "jump_can_skip_instructions")
+recipe main [
+  jump 1:offset
+  1:integer <- copy 1:literal
+]
++run: instruction main/0
++run: ingredient 0 is 1
+-run: instruction main/1
+-mem: storing 1 in location 1
+
+:(scenario "jump_backward")
+recipe main [
+  jump 1:offset  # 0 -+
+  jump 1:offset  #    |   +-+ 1
+                 #   \/  /\ |
+  jump -2:offset #  2 +-->+ |
+]                #         \/ 3
++run: instruction main/0
++run: instruction main/2
++run: instruction main/1
+
+:(before "End Primitive Recipe Declarations")
+JUMP_IF,
+:(before "End Primitive Recipe Numbers")
+Recipe_number["jump-if"] = JUMP_IF;
+:(before "End Primitive Recipe Implementations")
+case JUMP_IF: {
+  vector<int> arg0 = read_memory(instructions[pc].ingredients[0]);
+  assert(arg0.size() == 1);
+  trace("run") << "ingredient 0 is " << arg0[0];
+  if (!arg0[0]) {
+    trace("run") << "jump-if fell through";
+    break;
+  }
+  trace("run") << "ingredient 1 is " << instructions[pc].ingredients[1].name;
+  pc += instructions[pc].ingredients[1].value;
+  trace("run") << "jumping to instruction " << pc+1;
+  break;
+}
+
+:(scenario "jump_if")
+recipe main [
+  jump-if 999:literal 1:offset
+  1:integer <- copy 1:literal
+]
++run: instruction main/0
++run: ingredient 1 is 1
++run: jumping to instruction 2
+-run: instruction main/1
+-mem: storing 1 in location 1
+
+:(scenario "jump_if_fallthrough")
+recipe main [
+  jump-if 0:literal 1:offset
+  123:integer <- copy 1:literal
+]
++run: instruction main/0
++run: jump-if fell through
++run: instruction main/1
++mem: storing 1 in location 123
+
+:(before "End Primitive Recipe Declarations")
+JUMP_UNLESS,
+:(before "End Primitive Recipe Numbers")
+Recipe_number["jump-unless"] = JUMP_UNLESS;
+:(before "End Primitive Recipe Implementations")
+case JUMP_UNLESS: {
+  vector<int> arg0 = read_memory(instructions[pc].ingredients[0]);
+  assert(arg0.size() == 1);
+  trace("run") << "ingredient 0 is " << arg0[0];
+  if (arg0[0]) {
+    trace("run") << "jump-unless fell through";
+    break;
+  }
+  trace("run") << "ingredient 1 is " << instructions[pc].ingredients[1].name;
+  pc += instructions[pc].ingredients[1].value;
+  trace("run") << "jumping to instruction " << pc+1;
+  break;
+}
+
+:(scenario "jump_unless")
+recipe main [
+  jump-unless 0:literal 1:offset
+  1:integer <- copy 1:literal
+]
++run: instruction main/0
++run: ingredient 1 is 1
++run: jumping to instruction 2
+-run: instruction main/1
+-mem: storing 1 in location 1
+
+:(scenario "jump_unless_fallthrough")
+recipe main [
+  jump-unless 999:literal 1:offset
+  123:integer <- copy 1:literal
+]
++run: instruction main/0
++run: ingredient 0 is 999
++run: jump-unless fell through
++run: instruction main/1
++mem: storing 1 in location 123