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+/* MN10300 64-bit division
+ *
+ * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+#ifndef _ASM_DIV64
+#define _ASM_DIV64
+
+#include <linux/types.h>
+
+extern void ____unhandled_size_in_do_div___(void);
+
+/*
+ * 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
+ * through the MDR register
+ */
+#define do_div(n, base) \
+({ \
+ unsigned __rem = 0; \
+ if (sizeof(n) <= 4) { \
+ asm("mov %1,mdr \n" \
+ "divu %2,%0 \n" \
+ "mov mdr,%1 \n" \
+ : "+r"(n), "=d"(__rem) \
+ : "r"(base), "1"(__rem) \
+ : "cc" \
+ ); \
+ } else if (sizeof(n) <= 8) { \
+ union { \
+ unsigned long long l; \
+ u32 w[2]; \
+ } __quot; \
+ __quot.l = n; \
+ asm("mov %0,mdr \n" /* MDR = 0 */ \
+ "divu %3,%1 \n" \
+ /* __quot.MSL = __div.MSL / base, */ \
+ /* MDR = MDR:__div.MSL % base */ \
+ "divu %3,%2 \n" \
+ /* __quot.LSL = MDR:__div.LSL / base, */ \
+ /* MDR = MDR:__div.LSL % base */ \
+ "mov mdr,%0 \n" \
+ : "=d"(__rem), "=r"(__quot.w[1]), "=r"(__quot.w[0]) \
+ : "r"(base), "0"(__rem), "1"(__quot.w[1]), \
+ "2"(__quot.w[0]) \
+ : "cc" \
+ ); \
+ n = __quot.l; \
+ } else { \
+ ____unhandled_size_in_do_div___(); \
+ } \
+ __rem; \
+})
+
+/*
+ * do an unsigned 32-bit multiply and divide with intermediate 64-bit product
+ * so as not to lose accuracy
+ * - we use the MDR register to hold the MSW of the product
+ */
+static inline __attribute__((const))
+unsigned __muldiv64u(unsigned val, unsigned mult, unsigned div)
+{
+ unsigned result;
+
+ asm("mulu %2,%0 \n" /* MDR:val = val*mult */
+ "divu %3,%0 \n" /* val = MDR:val/div;
+ * MDR = MDR:val%div */
+ : "=r"(result)
+ : "0"(val), "ir"(mult), "r"(div)
+ );
+
+ return result;
+}
+
+/*
+ * do a signed 32-bit multiply and divide with intermediate 64-bit product so
+ * as not to lose accuracy
+ * - we use the MDR register to hold the MSW of the product
+ */
+static inline __attribute__((const))
+signed __muldiv64s(signed val, signed mult, signed div)
+{
+ signed result;
+
+ asm("mul %2,%0 \n" /* MDR:val = val*mult */
+ "div %3,%0 \n" /* val = MDR:val/div;
+ * MDR = MDR:val%div */
+ : "=r"(result)
+ : "0"(val), "ir"(mult), "r"(div)
+ );
+
+ return result;
+}
+
+extern __attribute__((const))
+uint64_t div64_64(uint64_t dividend, uint64_t divisor);
+
+#endif /* _ASM_DIV64 */