Reworking VM into infinite stack machine

bytecode_codegen.cpp

@@ -1,16 +1,57 @@
 
+function Register_Index
+allocate_register(Bc *b){
+  if(b->free_registers.len == 0){
+    Register_Index result = b->registers.addi({});
+    return result;
+  }
+
+  Register_Index index = b->free_registers.pop();
+  b->used_registers.add(index);
+  return index;
+}
+
 function void
+release_register(Bc *b, Register_Index reg){
+  if(reg == 0) return;
+
+  B32 found = false;
+  For(b->used_registers){
+    if(it == reg){
+      b->used_registers.unordered_remove(&it);
+      found = true;
+      break;
+    }
+  }
+
+  assert_msg(found, "Trying to release register that is not used");
+}
+
+
+function Register_Index
 bc_emit_expr(Bc *b, Ast *ast){
-  if(!ast) return;
+  if(!ast) return REG_NULL;
   if(!is_flag_set(ast->flags, AST_EXPR))
     compiler_error(ast->pos, "Internal compiler error: Trying to emit expression but it doesn't have appropriate flag");
   switch(ast->kind){
+    CASE(VALUE, Atom){
+      Register_Index dst = allocate_register(b);
+      U64 value = bigint_as_unsigned(&node->big_int_val);
+      emit_load_constant_s64(b, dst, value);
+      return dst;
+      BREAK();
+    }
     CASE(BINARY, Binary){
-
+      Register_Index left = bc_emit_expr(b, node->left);
+      Register_Index right = bc_emit_expr(b, node->right);
+      emit_arithmetic(b, BC_ADD_S64, left, right, left);
+      release_register(b, right);
+      return left;
       BREAK();
     }
     default:{}
   }
+  return REG_NULL;
 }
 
 function void
@@ -25,10 +66,17 @@ compile_to_bc(){
       }
       CASE(VAR, Decl){
         node->bytecode_data_position = exp_alloc(&b->memory, node->type->size, AF_ZeroMemory);
-        bc_emit_assign(b, node);
+        Register_Index index = bc_emit_expr(b, node->expr);
+        if(index!=REG_NULL){
+          // bc_emit_store(b, )
+        }
+        release_register(b, index);
         BREAK();
       }
       default: {}
     }
   }
+  emit_end(b);
+  run_bytecode_interp(b);
+  destroy_bytecode_interp(b);
 }