1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __ASM_ARM_DIV64
3 #define __ASM_ARM_DIV64
4
5 #include <linux/types.h>
6 #include <asm/compiler.h>
7
8 /*
9 * The semantics of __div64_32() are:
10 *
11 * uint32_t __div64_32(uint64_t *n, uint32_t base)
12 * {
13 * uint32_t remainder = *n % base;
14 * *n = *n / base;
15 * return remainder;
16 * }
17 *
18 * In other words, a 64-bit dividend with a 32-bit divisor producing
19 * a 64-bit result and a 32-bit remainder. To accomplish this optimally
20 * we override the generic version in lib/div64.c to call our __do_div64
21 * assembly implementation with completely non standard calling convention
22 * for arguments and results (beware).
23 */
24 static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
25 {
26 register unsigned int __base asm("r4") = base;
27 register unsigned long long __n asm("r0") = *n;
28 register unsigned long long __res asm("r2");
29 unsigned int __rem;
30 asm( __asmeq("%0", "r0")
31 __asmeq("%1", "r2")
32 __asmeq("%2", "r4")
33 "bl __do_div64"
34 : "+r" (__n), "=r" (__res)
35 : "r" (__base)
36 : "ip", "lr", "cc");
37 __rem = __n >> 32;
38 *n = __res;
39 return __rem;
40 }
41 #define __div64_32 __div64_32
42
43 #if !defined(CONFIG_AEABI)
44
45 /*
46 * In OABI configurations, some uses of the do_div function
47 * cause gcc to run out of registers. To work around that,
48 * we can force the use of the out-of-line version for
49 * configurations that build a OABI kernel.
50 */
51 #define do_div(n, base) __div64_32(&(n), base)
52
53 #else
54
55 static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias)
56 {
57 unsigned long long res;
58 register unsigned int tmp asm("ip") = 0;
59
60 if (!bias) {
61 asm ( "umull %Q0, %R0, %Q1, %Q2\n\t"
62 "mov %Q0, #0"
63 : "=&r" (res)
64 : "r" (m), "r" (n)
65 : "cc");
66 } else if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
67 res = m;
68 asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t"
69 "mov %Q0, #0"
70 : "+&r" (res)
71 : "r" (m), "r" (n)
72 : "cc");
73 } else {
74 asm ( "umull %Q0, %R0, %Q2, %Q3\n\t"
75 "cmn %Q0, %Q2\n\t"
76 "adcs %R0, %R0, %R2\n\t"
77 "adc %Q0, %1, #0"
78 : "=&r" (res), "+&r" (tmp)
79 : "r" (m), "r" (n)
80 : "cc");
81 }
82
83 if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
84 asm ( "umlal %R0, %Q0, %R1, %Q2\n\t"
85 "umlal %R0, %Q0, %Q1, %R2\n\t"
86 "mov %R0, #0\n\t"
87 "umlal %Q0, %R0, %R1, %R2"
88 : "+&r" (res)
89 : "r" (m), "r" (n)
90 : "cc");
91 } else {
92 asm ( "umlal %R0, %Q0, %R2, %Q3\n\t"
93 "umlal %R0, %1, %Q2, %R3\n\t"
94 "mov %R0, #0\n\t"
95 "adds %Q0, %1, %Q0\n\t"
96 "adc %R0, %R0, #0\n\t"
97 "umlal %Q0, %R0, %R2, %R3"
98 : "+&r" (res), "+&r" (tmp)
99 : "r" (m), "r" (n)
100 : "cc");
101 }
102
103 return res;
104 }
105 #define __arch_xprod_64 __arch_xprod_64
106
107 #include <asm-generic/div64.h>
108
109 #endif
110
111 #endif
112
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