| /* |
| * Copyright (c) 2023, Red Hat, Inc. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * 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. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| #include "jni.h" |
| |
| // See GCC bug 55522: |
| // |
| // "When used at link-time, [ GCC with -ffast-math ] may include |
| // libraries or startup files that change the default FPU control word |
| // or other similar optimizations." |
| // |
| // This breaks Java's floating point arithmetic. |
| |
| #if defined(__GNUC__) |
| |
| // On systems on which GCC bug 55522 has been fixed, this constructor |
| // serves to reproduce that bug for the purposes of testing HotSpot. |
| static void __attribute__((constructor)) set_flush_to_zero(void) { |
| |
| #if defined(__x86_64__) |
| |
| #define MXCSR_DAZ (1 << 6) /* Enable denormals are zero mode */ |
| #define MXCSR_FTZ (1 << 15) /* Enable flush to zero mode */ |
| unsigned int mxcsr = __builtin_ia32_stmxcsr (); |
| mxcsr |= MXCSR_DAZ | MXCSR_FTZ; |
| __builtin_ia32_ldmxcsr (mxcsr); |
| |
| #elif defined(__aarch64__) |
| |
| #define _FPU_FPCR_FZ (unsigned long)0x1000000 |
| #define _FPU_SETCW(fpcr) \ |
| __asm__ __volatile__ ("msr fpcr, %0" : : "r" (fpcr)); |
| |
| /* Flush to zero, round to nearest, IEEE exceptions disabled. */ |
| _FPU_SETCW (_FPU_FPCR_FZ); |
| |
| #endif // CPU arch |
| |
| } |
| #endif // defined(__GNUC__) |
