1/* MN10300 64-bit division 2 * 3 * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public Licence 8 * as published by the Free Software Foundation; either version 9 * 2 of the Licence, or (at your option) any later version. 10 */ 11#ifndef _ASM_DIV64 12#define _ASM_DIV64 13 14#include <linux/types.h> 15 16extern void ____unhandled_size_in_do_div___(void); 17 18/* 19 * divide n by base, leaving the result in n and returning the remainder 20 * - we can do this quite efficiently on the MN10300 by cascading the divides 21 * through the MDR register 22 */ 23#define do_div(n, base) \ 24({ \ 25 unsigned __rem = 0; \ 26 if (sizeof(n) <= 4) { \ 27 asm("mov %1,mdr \n" \ 28 "divu %2,%0 \n" \ 29 "mov mdr,%1 \n" \ 30 : "+r"(n), "=d"(__rem) \ 31 : "r"(base), "1"(__rem) \ 32 : "cc" \ 33 ); \ 34 } else if (sizeof(n) <= 8) { \ 35 union { \ 36 unsigned long long l; \ 37 u32 w[2]; \ 38 } __quot; \ 39 __quot.l = n; \ 40 asm("mov %0,mdr \n" /* MDR = 0 */ \ 41 "divu %3,%1 \n" \ 42 /* __quot.MSL = __div.MSL / base, */ \ 43 /* MDR = MDR:__div.MSL % base */ \ 44 "divu %3,%2 \n" \ 45 /* __quot.LSL = MDR:__div.LSL / base, */ \ 46 /* MDR = MDR:__div.LSL % base */ \ 47 "mov mdr,%0 \n" \ 48 : "=d"(__rem), "=r"(__quot.w[1]), "=r"(__quot.w[0]) \ 49 : "r"(base), "0"(__rem), "1"(__quot.w[1]), \ 50 "2"(__quot.w[0]) \ 51 : "cc" \ 52 ); \ 53 n = __quot.l; \ 54 } else { \ 55 ____unhandled_size_in_do_div___(); \ 56 } \ 57 __rem; \ 58}) 59 60/* 61 * do an unsigned 32-bit multiply and divide with intermediate 64-bit product 62 * so as not to lose accuracy 63 * - we use the MDR register to hold the MSW of the product 64 */ 65static inline __attribute__((const)) 66unsigned __muldiv64u(unsigned val, unsigned mult, unsigned div) 67{ 68 unsigned result; 69 70 asm("mulu %2,%0 \n" /* MDR:val = val*mult */ 71 "divu %3,%0 \n" /* val = MDR:val/div; 72 * MDR = MDR:val%div */ 73 : "=r"(result) 74 : "0"(val), "ir"(mult), "r"(div) 75 : "cc" 76 ); 77 78 return result; 79} 80 81/* 82 * do a signed 32-bit multiply and divide with intermediate 64-bit product so 83 * as not to lose accuracy 84 * - we use the MDR register to hold the MSW of the product 85 */ 86static inline __attribute__((const)) 87signed __muldiv64s(signed val, signed mult, signed div) 88{ 89 signed result; 90 91 asm("mul %2,%0 \n" /* MDR:val = val*mult */ 92 "div %3,%0 \n" /* val = MDR:val/div; 93 * MDR = MDR:val%div */ 94 : "=r"(result) 95 : "0"(val), "ir"(mult), "r"(div) 96 : "cc" 97 ); 98 99 return result; 100} 101 102#endif /* _ASM_DIV64 */ 103