From 7152ded5219453c9ff1cd062cecbeaf4d77e4cab Mon Sep 17 00:00:00 2001
From: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Date: Thu, 26 May 2016 15:05:48 +0200
Subject: [PATCH] Use <fenv.h> instead of <fpu_control.h>

musl libc (http://musl-libc.org lack the non-standard <fpu_control.h>
header, which is used in src/os/linux/{i386,x86_64}/init.c files to
setup the floating point precision. This patch makes it use the
standard C <fenv.h> header instead.

Original patch at Felix Janda at
https://sourceforge.net/p/jamvm/patches/6/.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 src/os/linux/i386/init.c   | 12 ++++++------
 src/os/linux/x86_64/init.c | 16 ++++++----------
 2 files changed, 12 insertions(+), 16 deletions(-)

diff --git a/src/os/linux/i386/init.c b/src/os/linux/i386/init.c
index d9c6648..94a733e 100644
--- a/src/os/linux/i386/init.c
+++ b/src/os/linux/i386/init.c
@@ -19,18 +19,18 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
-#include <fpu_control.h>
+#include <fenv.h>
 
 /* Change floating point precision to double (64-bit) from
  * the extended (80-bit) Linux default. */
 
 void setDoublePrecision() {
-    fpu_control_t cw;
+    fenv_t fenv;
 
-    _FPU_GETCW(cw);
-    cw &= ~_FPU_EXTENDED;
-    cw |= _FPU_DOUBLE;
-    _FPU_SETCW(cw);
+    fegetenv(&fenv);
+    fenv.__control_word &= ~0x300; /* _FPU_EXTENDED */
+    fenv.__control_word |= 0x200; /* _FPU_DOUBLE */
+    fesetenv(&fenv);
 }
 
 void initialisePlatform() {
diff --git a/src/os/linux/x86_64/init.c b/src/os/linux/x86_64/init.c
index 9d55229..a76a923 100644
--- a/src/os/linux/x86_64/init.c
+++ b/src/os/linux/x86_64/init.c
@@ -19,9 +19,7 @@
  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
-#ifdef __linux__
-#include <fpu_control.h>
-#endif
+#include <fenv.h>
 
 /* Change the x87 FPU precision to double (64-bit) from the extended
    (80-bit) Linux default.  Note, unlike on i386, my testcases pass
@@ -30,14 +28,12 @@
 */
 
 void setDoublePrecision() {
-#ifdef __linux__
-    fpu_control_t cw;
+    fenv_t fenv;
 
-    _FPU_GETCW(cw);
-    cw &= ~_FPU_EXTENDED;
-    cw |= _FPU_DOUBLE;
-    _FPU_SETCW(cw);
-#endif
+    fegetenv(&fenv);
+    fenv.__control_word &= ~0x300; /*_FPU_EXTENDED */
+    fenv.__control_word |= 0x200; /*_FPU_DOUBLE */
+    fesetenv(&fenv);
 }
 
 void initialisePlatform() {
-- 
2.7.4