Add incomplet long double math support to libmingwex.a

1 files changed, 23 insertions, 0 deletions

diff --git a/winsup/mingw/mingwex/math/llroundf.c b/winsup/mingw/mingwex/math/llroundf.c
new file mode 100644
index 000000000..b6c431f9d
--- /dev/null
+++ b/winsup/mingw/mingwex/math/llroundf.c
@@ -0,0 +1,23 @@
+#include <fenv.h>
+#include <math.h>
+
+long long
+llroundf (float x) {
+  long long retval;
+  unsigned short saved_cw, _cw;
+  __asm__ (
+	"fnstcw %0;" : "=m" (saved_cw)
+	); /* save  control word  */
+  _cw = ~(FE_TONEAREST | FE_DOWNWARD | FE_UPWARD | FE_TOWARDZERO)
+     	  | (x > 0.0 ? FE_UPWARD : FE_DOWNWARD); /* round away from zero */
+  __asm__ (
+	"fldcw %0;" : : "m" (_cw)
+	);  /* load the rounding control */
+  __asm__ __volatile__ (
+	"fistpll %0"  : "=m" (retval) : "t" (x) : "st"
+	);
+  __asm__ (
+	"fldcw %0;" : : "m" (saved_cw)
+	); /* restore control word */
+  return retval;
+}