x86: unify div64{,_32,_64}.h

Unify x86 div64.h headers.

Signed-off-by: Chris Snook <csnook@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 57 insertions, 3 deletions

diff --git a/include/asm-x86/div64.h b/include/asm-x86/div64.h
index 8ac7da6ca284..e98d16e7a37a 100644
--- a/include/asm-x86/div64.h
+++ b/include/asm-x86/div64.h
@@ -1,5 +1,59 @@
+#ifndef _ASM_X86_DIV64_H
+#define _ASM_X86_DIV64_H
+
 #ifdef CONFIG_X86_32
-# include "div64_32.h"
+
+#include <linux/types.h>
+
+/*
+ * do_div() is NOT a C function. It wants to return
+ * two values (the quotient and the remainder), but
+ * since that doesn't work very well in C, what it
+ * does is:
+ *
+ * - modifies the 64-bit dividend _in_place_
+ * - returns the 32-bit remainder
+ *
+ * This ends up being the most efficient "calling
+ * convention" on x86.
+ */
+#define do_div(n,base) ({ \
+        unsigned long __upper, __low, __high, __mod, __base; \
+        __base = (base); \
+        asm("":"=a" (__low), "=d" (__high):"A" (n)); \
+        __upper = __high; \
+        if (__high) { \
+                __upper = __high % (__base); \
+                __high = __high / (__base); \
+        } \
+        asm("divl %2":"=a" (__low), "=d" (__mod):"rm" (__base), "0" (__low), "1" (__upper)); \
+        asm("":"=A" (n):"a" (__low),"d" (__high)); \
+        __mod; \
+})
+
+/*
+ * (long)X = ((long long)divs) / (long)div
+ * (long)rem = ((long long)divs) % (long)div
+ *
+ * Warning, this will do an exception if X overflows.
+ */
+#define div_long_long_rem(a,b,c) div_ll_X_l_rem(a,b,c)
+
+static inline long
+div_ll_X_l_rem(long long divs, long div, long *rem)
+{
+        long dum2;
+      __asm__("divl %2":"=a"(dum2), "=d"(*rem)
+      : "rm"(div), "A"(divs));
+
+        return dum2;
+
+}
+
+extern uint64_t div64_64(uint64_t dividend, uint64_t divisor);
+
 #else
-# include "div64_64.h"
-#endif
+# include <asm-generic/div64.h>
+#endif /* CONFIG_X86_32 */
+
+#endif /* _ASM_X86_DIV64_H */