/* 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; } #endif /* _ASM_DIV64 */