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git.proxmox.com Git - mirror_ubuntu-focal-kernel.git/blob - arch/arm/include/asm/div64.h
1 #ifndef __ASM_ARM_DIV64
2 #define __ASM_ARM_DIV64
4 #include <linux/types.h>
5 #include <asm/compiler.h>
8 * The semantics of __div64_32() are:
10 * uint32_t __div64_32(uint64_t *n, uint32_t base)
12 * uint32_t remainder = *n % base;
17 * In other words, a 64-bit dividend with a 32-bit divisor producing
18 * a 64-bit result and a 32-bit remainder. To accomplish this optimally
19 * we override the generic version in lib/div64.c to call our __do_div64
20 * assembly implementation with completely non standard calling convention
21 * for arguments and results (beware).
32 static inline uint32_t __div64_32(uint64_t *n
, uint32_t base
)
34 register unsigned int __base
asm("r4") = base
;
35 register unsigned long long __n
asm("r0") = *n
;
36 register unsigned long long __res
asm("r2");
37 register unsigned int __rem
asm(__xh
);
38 asm( __asmeq("%0", __xh
)
43 : "=r" (__rem
), "=r" (__res
)
44 : "r" (__n
), "r" (__base
)
49 #define __div64_32 __div64_32
51 #if !defined(CONFIG_AEABI)
54 * In OABI configurations, some uses of the do_div function
55 * cause gcc to run out of registers. To work around that,
56 * we can force the use of the out-of-line version for
57 * configurations that build a OABI kernel.
59 #define do_div(n, base) __div64_32(&(n), base)
64 * gcc versions earlier than 4.0 are simply too problematic for the
65 * __div64_const32() code in asm-generic/div64.h. First there is
66 * gcc PR 15089 that tend to trig on more complex constructs, spurious
67 * .global __udivsi3 are inserted even if none of those symbols are
68 * referenced in the generated code, and those gcc versions are not able
69 * to do constant propagation on long long values anyway.
72 #define __div64_const32_is_OK (__GNUC__ >= 4)
74 static inline uint64_t __arch_xprod_64(uint64_t m
, uint64_t n
, bool bias
)
76 unsigned long long res
;
77 register unsigned int tmp
asm("ip") = 0;
80 asm ( "umull %Q0, %R0, %Q1, %Q2\n\t"
85 } else if (!(m
& ((1ULL << 63) | (1ULL << 31)))) {
87 asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t"
93 asm ( "umull %Q0, %R0, %Q2, %Q3\n\t"
95 "adcs %R0, %R0, %R2\n\t"
97 : "=&r" (res
), "+&r" (tmp
)
102 if (!(m
& ((1ULL << 63) | (1ULL << 31)))) {
103 asm ( "umlal %R0, %Q0, %R1, %Q2\n\t"
104 "umlal %R0, %Q0, %Q1, %R2\n\t"
106 "umlal %Q0, %R0, %R1, %R2"
111 asm ( "umlal %R0, %Q0, %R2, %Q3\n\t"
112 "umlal %R0, %1, %Q2, %R3\n\t"
114 "adds %Q0, %1, %Q0\n\t"
115 "adc %R0, %R0, #0\n\t"
116 "umlal %Q0, %R0, %R2, %R3"
117 : "+&r" (res
), "+&r" (tmp
)
124 #define __arch_xprod_64 __arch_xprod_64
126 #include <asm-generic/div64.h>