X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=include%2Flibfirm%2Firarch.h;h=278bdfd19158deef2b154cc07e7566ae95752269;hb=188a17803798f8d78b1c02c3b68976056bce33d9;hp=7465fdc57eef42940769a91104531312b2cec610;hpb=dbfc39c03e665d1711b6d2e82b9d956282c951bb;p=libfirm

diff --git a/include/libfirm/irarch.h b/include/libfirm/irarch.h
index 7465fdc57..278bdfd19 100644
--- a/include/libfirm/irarch.h
+++ b/include/libfirm/irarch.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 1995-2007 University of Karlsruhe.  All right reserved.
+ * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
  *
  * This file is part of libFirm.
  *
@@ -39,7 +39,7 @@ typedef enum instr {
 	ADD,   /**< the ADD instruction */
 	ZERO,  /**< creates a ZERO constant */
 	MUL,   /**< the original MUL instruction */
-	ROOT,  /**< the ROOT value that is multiplied */
+	ROOT   /**< the ROOT value that is multiplied */
 } insn_kind;
 
 /**
@@ -59,7 +59,7 @@ typedef int (*evaluate_costs_func)(insn_kind kind, tarval *tv);
 struct ir_settings_arch_dep_t {
 	/* Mul optimization */
 	unsigned also_use_subs : 1;    /**< Use also Subs when resolving Muls to shifts */
-	int maximum_shifts;            /**< The maximum number of shifts that shall be inserted for a mul. */
+	unsigned maximum_shifts;            /**< The maximum number of shifts that shall be inserted for a mul. */
 	unsigned highest_shift_amount; /**< The highest shift amount you want to
 	                                    tolerate. Muls which would require a higher
 	                                    shift constant are left. */
@@ -68,7 +68,7 @@ struct ir_settings_arch_dep_t {
 	/* Div/Mod optimization */
 	unsigned allow_mulhs   : 1;    /**< Use the Mulhs operation for division by constant */
 	unsigned allow_mulhu   : 1;    /**< Use the Mulhu operation for division by constant */
-	int max_bits_for_mulh;         /**< Maximum number of bits the Mulh operation can take.
+	unsigned max_bits_for_mulh;         /**< Maximum number of bits the Mulh operation can take.
 	                                    Modes with higher amount of bits will use Mulh */
 };
 
@@ -109,16 +109,8 @@ void arch_dep_init(arch_dep_params_factory_t factory);
 void arch_dep_set_opts(arch_dep_opts_t opts);
 
 /**
- * Replace Muls with Shifts and Add/Subs.
- * This function is driven by the 3 parameters:
- * - also_use_subs
- * - maximum_shifts
- * - highest_shift_amount
- *
- * If irn is a Mul with a Const, the constant is inspected if it meets the
- * requirements of the three variables stated above. If a Shl/Add/Sub
- * sequence can be generated that meets these requirements, this expression
- * is returned. In each other case irn is returned unmodified.
+ * Replace Muls with Lea/Shifts/Add/Subs if these
+ * have smaller costs than the original multiplication.
  *
  * @param irn       The Firm node to inspect.
  * @return          A replacement expression for irn.