<?xml version="1.0" encoding="UTF-8"?> <!-- Copyright (c) 2017 OpenPOWER Foundation Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. --> <section xmlns="http://docbook.org/ns/docbook" xmlns:xi="http://www.w3.org/2001/XInclude" xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0" xml:id="sec_floatingpoint_rounding"> <title>Floating-point rounding modes</title> <para>The Intel (x86 / x86_64) and PowerISA architectures both support the 4 IEEE-754 rounding modes. Again while the Intel Intrinsic API allows the application to change rounding modes via updates to the <literal>MXCSR</literal> it is a bad idea and should be replaced with the POSIX APIs (<literal>fegetround</literal> and <literal>fesetround</literal>). </para> </section>