MN10300: gcc 4.6 vs am33 inline assembly

[pandora-kernel.git] / arch / mn10300 / include / asm / div64.h

diff --git a/arch/mn10300/include/asm/div64.h b/arch/mn10300/include/asm/div64.h
index 34dcb8e..503efab 100644 (file)
--- a/arch/mn10300/include/asm/div64.h
+++ b/arch/mn10300/include/asm/div64.h
@@ -15,6 +15,19 @@
 
 extern void ____unhandled_size_in_do_div___(void);
 
+/*
+ * Beginning with gcc 4.6, the MDR register is represented explicitly.  We
+ * must, therefore, at least explicitly clobber the register when we make
+ * changes to it.  The following assembly fragments *could* be rearranged in
+ * order to leave the moves to/from the MDR register to the compiler, but the
+ * gains would be minimal at best.
+ */
+#if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 6)
+# define CLOBBER_MDR_CC                "mdr", "cc"
+#else
+# define CLOBBER_MDR_CC                "cc"
+#endif
+
 /*
  * divide n by base, leaving the result in n and returning the remainder
  * - we can do this quite efficiently on the MN10300 by cascading the divides
@@ -29,7 +42,7 @@ extern void ____unhandled_size_in_do_div___(void);
                    "mov        mdr,%1  \n"                             \
                    : "+r"(n), "=d"(__rem)                              \
                    : "r"(base), "1"(__rem)                             \
-                   : "cc"                                              \
+                   : CLOBBER_MDR_CC                                    \
                    );                                                  \
        } else if (sizeof(n) <= 8) {                                    \
                union {                                                 \
@@ -48,7 +61,7 @@ extern void ____unhandled_size_in_do_div___(void);
                    : "=d"(__rem), "=r"(__quot.w[1]), "=r"(__quot.w[0]) \
                    : "r"(base), "0"(__rem), "1"(__quot.w[1]),          \
                      "2"(__quot.w[0])                                  \
-                   : "cc"                                              \
+                   : CLOBBER_MDR_CC                                    \
                    );                                                  \
                n = __quot.l;                                           \
        } else {                                                        \
@@ -72,7 +85,7 @@ unsigned __muldiv64u(unsigned val, unsigned mult, unsigned div)
                                         * MDR = MDR:val%div */
            : "=r"(result)
            : "0"(val), "ir"(mult), "r"(div)
-           : "cc"
+           : CLOBBER_MDR_CC
            );
 
        return result;
@@ -93,7 +106,7 @@ signed __muldiv64s(signed val, signed mult, signed div)
                                         * MDR = MDR:val%div */
            : "=r"(result)
            : "0"(val), "ir"(mult), "r"(div)
-           : "cc"
+           : CLOBBER_MDR_CC
            );
 
        return result;