[PATCH] msvcrt: Don't set MXCSR in _control87.

[Myah Caron]

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=27594
Signed-off-by: Myah Caron 
---
This appears to match native MSVCRT's behavior, at least the one provided by vcrun6.

I'm not sure if the style is correct (the helper being directly below the __control87_2 comment).
---
 dlls/msvcrt/math.c | 61 +++++++++++++++++++++++++++++-----------------
 1 file changed, 38 insertions(+), 23 deletions(-)

diff --git a/dlls/msvcrt/math.c b/dlls/msvcrt/math.c
index eae917076f..7ad79a07e5 100644
--- a/dlls/msvcrt/math.c
+++ b/dlls/msvcrt/math.c
@@ -1101,6 +1101,41 @@ double CDECL MSVCRT__chgsign(double num)
  * Not exported by native msvcrt, added in msvcr80.
  */
 #ifdef __i386__
+static unsigned int get_flags_from_mxcsr(void) {
+#ifdef __GNUC__
+    unsigned long fpword;
+    unsigned int flags;
+
+    __asm__ __volatile__( "stmxcsr %0" : "=m" (fpword) );
+
+    /* Convert into mask constants */
+    flags = 0;
+    if (fpword & 0x80)   flags |= MSVCRT__EM_INVALID;
+    if (fpword & 0x100)  flags |= MSVCRT__EM_DENORMAL;
+    if (fpword & 0x200)  flags |= MSVCRT__EM_ZERODIVIDE;
+    if (fpword & 0x400)  flags |= MSVCRT__EM_OVERFLOW;
+    if (fpword & 0x800)  flags |= MSVCRT__EM_UNDERFLOW;
+    if (fpword & 0x1000) flags |= MSVCRT__EM_INEXACT;
+    switch (fpword & 0x6000)
+    {
+    case 0x6000: flags |= MSVCRT__RC_UP|MSVCRT__RC_DOWN; break;
+    case 0x4000: flags |= MSVCRT__RC_UP; break;
+    case 0x2000: flags |= MSVCRT__RC_DOWN; break;
+    }
+    switch (fpword & 0x8040)
+    {
+    case 0x0040: flags |= MSVCRT__DN_FLUSH_OPERANDS_SAVE_RESULTS; break;
+    case 0x8000: flags |= MSVCRT__DN_SAVE_OPERANDS_FLUSH_RESULTS; break;
+    case 0x8040: flags |= MSVCRT__DN_FLUSH; break;
+    }
+
+    return flags;
+#else
+    FIXME( "not implemented\n" );
+    return 0;
+#endif
+}
+
 int CDECL __control87_2( unsigned int newval, unsigned int mask,
                          unsigned int *x86_cw, unsigned int *sse2_cw )
 {
@@ -1170,28 +1205,7 @@ int CDECL __control87_2( unsigned int newval, unsigned int mask,

if (sse2_supported)
     {
-        __asm__ __volatile__( "stmxcsr %0" : "=m" (fpword) );
-
-        /* Convert into mask constants */
-        flags = 0;
-        if (fpword & 0x80)   flags |= MSVCRT__EM_INVALID;
-        if (fpword & 0x100)  flags |= MSVCRT__EM_DENORMAL;
-        if (fpword & 0x200)  flags |= MSVCRT__EM_ZERODIVIDE;
-        if (fpword & 0x400)  flags |= MSVCRT__EM_OVERFLOW;
-        if (fpword & 0x800)  flags |= MSVCRT__EM_UNDERFLOW;
-        if (fpword & 0x1000) flags |= MSVCRT__EM_INEXACT;
-        switch (fpword & 0x6000)
-        {
-        case 0x6000: flags |= MSVCRT__RC_UP|MSVCRT__RC_DOWN; break;
-        case 0x4000: flags |= MSVCRT__RC_UP; break;
-        case 0x2000: flags |= MSVCRT__RC_DOWN; break;
-        }
-        switch (fpword & 0x8040)
-        {
-        case 0x0040: flags |= MSVCRT__DN_FLUSH_OPERANDS_SAVE_RESULTS; break;
-        case 0x8000: flags |= MSVCRT__DN_SAVE_OPERANDS_FLUSH_RESULTS; break;
-        case 0x8040: flags |= MSVCRT__DN_FLUSH; break;
-        }
+        flags = get_flags_from_mxcsr();

TRACE( "sse2 flags=%08x newval=%08x mask=%08x\n", flags, newval, mask );
         if (mask)
@@ -1241,7 +1255,8 @@ unsigned int CDECL _control87(unsigned int newval, unsigned int mask)
 #ifdef __i386__
     unsigned int sse2_cw;

-    __control87_2( newval, mask, &flags, &sse2_cw );
+    __control87_2( newval, mask, &flags, 0 );
+    sse2_cw = get_flags_from_mxcsr();

if ((flags ^ sse2_cw) & (MSVCRT__MCW_EM | MSVCRT__MCW_RC)) flags |= MSVCRT__EM_AMBIGUOUS;
 #elif defined(__x86_64__)
--
2.26.2