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 */
24static 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
55static 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