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--- old/src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp
+++ new/src/hotspot/os_cpu/linux_x86/os_linux_x86.cpp
@@ -90,6 +90,126 @@
#define SPELL_REG_FP "ebp"
#endif // AMD64
+// ==============================================================================
+// Taken from glibc 2.28
+// source: https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/x86/fpu_control.h;h=4cb98c5679b2897ff4e5826d228cba6be589e24d;hb=3c03baca37fdcb52c3881e653ca392bba7a99c2b
+// ==============================================================================
+#ifndef AMD64
+/* FPU control word bits. x86 version.
+ Copyright (C) 1993-2018 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Olaf Flebbe.
+
+ The GNU C 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.
+
+ The GNU C 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 the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#ifndef _FPU_CONTROL_H
+#define _FPU_CONTROL_H 1
+
+/* Note that this file sets on x86-64 only the x87 FPU, it does not
+ touch the SSE unit. */
+
+/* Here is the dirty part. Set up your 387 through the control word
+ * (cw) register.
+ *
+ * 15-13 12 11-10 9-8 7-6 5 4 3 2 1 0
+ * | reserved | IC | RC | PC | reserved | PM | UM | OM | ZM | DM | IM
+ *
+ * IM: Invalid operation mask
+ * DM: Denormalized operand mask
+ * ZM: Zero-divide mask
+ * OM: Overflow mask
+ * UM: Underflow mask
+ * PM: Precision (inexact result) mask
+ *
+ * Mask bit is 1 means no interrupt.
+ *
+ * PC: Precision control
+ * 11 - round to extended precision
+ * 10 - round to double precision
+ * 00 - round to single precision
+ *
+ * RC: Rounding control
+ * 00 - rounding to nearest
+ * 01 - rounding down (toward - infinity)
+ * 10 - rounding up (toward + infinity)
+ * 11 - rounding toward zero
+ *
+ * IC: Infinity control
+ * That is for 8087 and 80287 only.
+ *
+ * The hardware default is 0x037f which we use.
+ */
+
+#include <features.h>
+
+/* masking of interrupts */
+#define _FPU_MASK_IM 0x01
+#define _FPU_MASK_DM 0x02
+#define _FPU_MASK_ZM 0x04
+#define _FPU_MASK_OM 0x08
+#define _FPU_MASK_UM 0x10
+#define _FPU_MASK_PM 0x20
+
+/* precision control */
+#define _FPU_EXTENDED 0x300 /* libm requires double extended precision. */
+#define _FPU_DOUBLE 0x200
+#define _FPU_SINGLE 0x0
+
+/* rounding control */
+#define _FPU_RC_NEAREST 0x0 /* RECOMMENDED */
+#define _FPU_RC_DOWN 0x400
+#define _FPU_RC_UP 0x800
+#define _FPU_RC_ZERO 0xC00
+
+#define _FPU_RESERVED 0xF0C0 /* Reserved bits in cw */
+
+
+/* The fdlibm code requires strict IEEE double precision arithmetic,
+ and no interrupts for exceptions, rounding to nearest. */
+
+#define _FPU_DEFAULT 0x037f
+
+/* IEEE: same as above. */
+#define _FPU_IEEE 0x037f
+
+/* Type of the control word. */
+typedef unsigned int fpu_control_t __attribute__ ((__mode__ (__HI__)));
+
+/* Macros for accessing the hardware control word. "*&" is used to
+ work around a bug in older versions of GCC. __volatile__ is used
+ to support combination of writing the control register and reading
+ it back. Without __volatile__, the old value may be used for reading
+ back under compiler optimization.
+
+ Note that the use of these macros is not sufficient anymore with
+ recent hardware nor on x86-64. Some floating point operations are
+ executed in the SSE/SSE2 engines which have their own control and
+ status register. */
+#define _FPU_GETCW(cw) __asm__ __volatile__ ("fnstcw %0" : "=m" (*&cw))
+#define _FPU_SETCW(cw) __asm__ __volatile__ ("fldcw %0" : : "m" (*&cw))
+
+/* Default control word set at startup. */
+extern fpu_control_t __fpu_control;
+
+#endif /* fpu_control.h */
+
+#endif // AMD64
+// ==============================================================================
+// ==============================================================================
+// ==============================================================================
+
address os::current_stack_pointer() {
#ifdef SPARC_WORKS
register void *esp;
|
