[Qemu-devel] [PATCH] tcg-target.inc.c: Use byte form of xgetbv instruction

[John Arbuckle]

The assembler in most versions of Mac OS X is pretty old and does not support
the xgetbv instruction. To go around this problem the raw encoding of the
instruction is used instead.

Signed-off-by: John Arbuckle <address@hidden>
---
 tcg/i386/tcg-target.inc.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tcg/i386/tcg-target.inc.c b/tcg/i386/tcg-target.inc.c
index 5357909..82e004a 100644
--- a/tcg/i386/tcg-target.inc.c
+++ b/tcg/i386/tcg-target.inc.c
@@ -3501,7 +3501,11 @@ static void tcg_target_init(TCGContext *s)
            sure of not hitting invalid opcode.  */
         if (c & bit_OSXSAVE) {
             unsigned xcrl, xcrh;
-            asm ("xgetbv" : "=a" (xcrl), "=d" (xcrh) : "c" (0));
+            /*
+             * The xgetbv instruction is not available to older versions of 
the 
+             * assembler, so we encode the instruction manually.
+             */
+            asm (".byte 0x0f, 0x01, 0xd0": "=a" (xcrl), "=d" (xcrh) : "c" (0));
             if ((xcrl & 6) == 6) {
                 have_avx1 = (c & bit_AVX) != 0;
                 have_avx2 = (b7 & bit_AVX2) != 0;
-- 
2.10.2