/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.vm.x86.compiler.l1a;
import org.jnode.assembler.x86.X86Assembler;
import org.jnode.assembler.x86.X86Register;
import org.jnode.assembler.x86.X86Register.FPU;
import org.jnode.vm.bytecode.StackException;
/**
* @author Ewout Prangsma (epr@users.sourceforge.net)
*/
final class FPUHelper {
/**
* Swap ST0 and the given item. Action is emitted to code & performed on
* fpuStack.
*
* @param os
* @param fpuStack
* @param item
*/
static void fxch(X86Assembler os, FPUStack fpuStack, Item item) {
if (!fpuStack.isTos(item)) {
final FPU fpuReg = fpuStack.getRegister(item);
fxch(os, fpuStack, fpuReg);
}
}
/**
* Swap ST0 and fpuReg. Action is emitted to code & performed on fpuStack.
*
* @param os
* @param fpuStack
* @param fpuReg
*/
static void fxch(X86Assembler os, FPUStack fpuStack,
FPU fpuReg) {
if (fpuReg == X86Register.ST0) {
throw new StackException("Cannot fxch ST0");
}
os.writeFXCH(fpuReg);
fpuStack.fxch(fpuReg);
}
}