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b920de1b DH |
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 | ||
16 | extern 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 | */ | |
65 | static inline __attribute__((const)) | |
66 | unsigned __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 | ); | |
76 | ||
77 | return result; | |
78 | } | |
79 | ||
80 | /* | |
81 | * do a signed 32-bit multiply and divide with intermediate 64-bit product so | |
82 | * as not to lose accuracy | |
83 | * - we use the MDR register to hold the MSW of the product | |
84 | */ | |
85 | static inline __attribute__((const)) | |
86 | signed __muldiv64s(signed val, signed mult, signed div) | |
87 | { | |
88 | signed result; | |
89 | ||
90 | asm("mul %2,%0 \n" /* MDR:val = val*mult */ | |
91 | "div %3,%0 \n" /* val = MDR:val/div; | |
92 | * MDR = MDR:val%div */ | |
93 | : "=r"(result) | |
94 | : "0"(val), "ir"(mult), "r"(div) | |
95 | ); | |
96 | ||
97 | return result; | |
98 | } | |
99 | ||
b920de1b | 100 | #endif /* _ASM_DIV64 */ |