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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package sun.tools.tree;

import sun.tools.java.*;
import sun.tools.asm.Assembler;
import sun.tools.asm.Label;
import java.util.Hashtable;

WARNING: The contents of this source file are not part of any supported API. Code that depends on them does so at its own risk: they are subject to change or removal without notice.
/** * WARNING: The contents of this source file are not part of any * supported API. Code that depends on them does so at its own risk: * they are subject to change or removal without notice. */
public class NotExpression extends UnaryExpression {
Constructor
/** * Constructor */
public NotExpression(long where, Expression right) { super(NOT, where, Type.tBoolean, right); }
Select the type of the expression
/** * Select the type of the expression */
void selectType(Environment env, Context ctx, int tm) { right = convert(env, ctx, Type.tBoolean, right); } /* * Check a "not" expression. * * cvars is modified so that * cvar.vsTrue indicates variables with a known value if * the expression is true. * cvars.vsFalse indicates variables with a known value if * the expression is false * * For "not" expressions, we look at the inside expression, and then * swap true and false. */ public void checkCondition(Environment env, Context ctx, Vset vset, Hashtable<Object, Object> exp, ConditionVars cvars) { right.checkCondition(env, ctx, vset, exp, cvars); right = convert(env, ctx, Type.tBoolean, right); // swap true and false Vset temp = cvars.vsFalse; cvars.vsFalse = cvars.vsTrue; cvars.vsTrue = temp; }
Evaluate
/** * Evaluate */
Expression eval(boolean a) { return new BooleanExpression(where, !a); }
Simplify
/** * Simplify */
Expression simplify() { // Check if the expression can be optimized switch (right.op) { case NOT: return ((NotExpression)right).right; case EQ: case NE: case LT: case LE: case GT: case GE: break; default: return this; } // Can't negate real comparisons BinaryExpression bin = (BinaryExpression)right; if (bin.left.type.inMask(TM_REAL)) { return this; } // Negate comparison switch (right.op) { case EQ: return new NotEqualExpression(where, bin.left, bin.right); case NE: return new EqualExpression(where, bin.left, bin.right); case LT: return new GreaterOrEqualExpression(where, bin.left, bin.right); case LE: return new GreaterExpression(where, bin.left, bin.right); case GT: return new LessOrEqualExpression(where, bin.left, bin.right); case GE: return new LessExpression(where, bin.left, bin.right); } return this; }
Code
/** * Code */
void codeBranch(Environment env, Context ctx, Assembler asm, Label lbl, boolean whenTrue) { right.codeBranch(env, ctx, asm, lbl, !whenTrue); }
Instead of relying on the default code generation which uses conditional branching, generate a simpler stream using XOR.
/** * Instead of relying on the default code generation which uses * conditional branching, generate a simpler stream using XOR. */
public void codeValue(Environment env, Context ctx, Assembler asm) { right.codeValue(env, ctx, asm); asm.add(where, opc_ldc, 1); asm.add(where, opc_ixor); } }