oops, forgot to add a file

diff --git a/ir/lower/lower_mode_b.h b/ir/lower/lower_mode_b.h
new file mode 100644 (file)
index 0000000..9f86325
--- /dev/null
+++ b/ir/lower/lower_mode_b.h
@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 1995-2011 University of Karlsruhe.  All right reserved.
+ *
+ * This file is part of libFirm.
+ *
+ * This file may be distributed and/or modified under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation and appearing in the file LICENSE.GPL included in the
+ * packaging of this file.
+ *
+ * Licensees holding valid libFirm Professional Edition licenses may use
+ * this file in accordance with the libFirm Commercial License.
+ * Agreement provided with the Software.
+ *
+ * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+ * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE.
+ */
+
+/**
+ * @file
+ * @brief       lower mode_b operations to something the backend can handle
+ * @author      Matthias Braun, Christoph Mallon
+ * @version     $Id$
+ *
+ * Most machines can't really manipulate mode_b values (which are usually
+ * modeled as cpu flags). So you often have to convert them into machine words
+ * with the values 0/1 and operate on them instead.
+ *
+ * After this pass the following holds:
+ *   - The only inputs with mode_b are for the Cond node and the Sel input of
+ *     a Mux node.
+ *   - The only nodes producing mode_b are: Proj(Cmp)
+ */
+#ifndef FIRM_LOWER_MODE_B_H
+#define FIRM_LOWER_MODE_B_H
+
+#include "firm_types.h"
+
+/**
+ * Function which creates a "set" instraction. A "set" instruction takes a
+ * condition value (a value with mode_b) as input and produces a value in a
+ * general purpose integer mode.
+ * Most architectures have special intrinsics for this. But if all else fails
+ * you can just produces the an if-like construct.
+ */
+typedef ir_node* (*create_set_func)(ir_node *cond);
+
+/**
+ * implementation of create_set_func which produces a cond with control
+ * flow
+ */
+ir_node *ir_create_cond_set(ir_node *cond, ir_mode *dest_mode);
+
+typedef struct lower_mode_b_config_t {
+       /* mode that is used to transport 0/1 values */
+       ir_mode *lowered_mode;
+       /* callback for creating set-like instructions */
+       create_set_func create_set;
+} lower_mode_b_config_t;
+
+/**
+ * Lowers mode_b operations to integer arithmetic. After the lowering the only
+ * operations with mode_b are the Projs of Cmps; the only nodes with mode_b
+ * inputs are Cond and Psi nodes.
+ *
+ * Example: Psi(a < 0, 1, 0) => a >> 31
+ *
+ * @param irg      the firm graph to lower
+ * @param config   configuration for mode_b lowerer
+ */
+void ir_lower_mode_b(ir_graph *irg, const lower_mode_b_config_t *config);
+
+#endif