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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __ASM_ARM_DIV64
#define __ASM_ARM_DIV64
#include <linux/types.h>
#include <asm/compiler.h>
/*
* The semantics of __div64_32() are:
*
* uint32_t __div64_32(uint64_t *n, uint32_t base)
* {
* uint32_t remainder = *n % base;
* *n = *n / base;
* return remainder;
* }
*
* In other words, a 64-bit dividend with a 32-bit divisor producing
* a 64-bit result and a 32-bit remainder. To accomplish this optimally
* we override the generic version in lib/div64.c to call our __do_div64
* assembly implementation with completely non standard calling convention
* for arguments and results (beware).
*/
static inline uint32_t __div64_32(uint64_t *n, uint32_t base)
{
register unsigned int __base asm("r4") = base;
register unsigned long long __n asm("r0") = *n;
register unsigned long long __res asm("r2");
unsigned int __rem;
asm( __asmeq("%0", "r0")
__asmeq("%1", "r2")
__asmeq("%2", "r4")
"bl __do_div64"
: "+r" (__n), "=r" (__res)
: "r" (__base)
: "ip", "lr", "cc");
__rem = __n >> 32;
*n = __res;
return __rem;
}
#define __div64_32 __div64_32
#if !defined(CONFIG_AEABI)
/*
* In OABI configurations, some uses of the do_div function
* cause gcc to run out of registers. To work around that,
* we can force the use of the out-of-line version for
* configurations that build a OABI kernel.
*/
#define do_div(n, base) __div64_32(&(n), base)
#else
/*
* gcc versions earlier than 4.0 are simply too problematic for the
* __div64_const32() code in asm-generic/div64.h. First there is
* gcc PR 15089 that tend to trig on more complex constructs, spurious
* .global __udivsi3 are inserted even if none of those symbols are
* referenced in the generated code, and those gcc versions are not able
* to do constant propagation on long long values anyway.
*/
#define __div64_const32_is_OK (__GNUC__ >= 4)
static inline uint64_t __arch_xprod_64(uint64_t m, uint64_t n, bool bias)
{
unsigned long long res;
register unsigned int tmp asm("ip") = 0;
if (!bias) {
asm ( "umull %Q0, %R0, %Q1, %Q2\n\t"
"mov %Q0, #0"
: "=&r" (res)
: "r" (m), "r" (n)
: "cc");
} else if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
res = m;
asm ( "umlal %Q0, %R0, %Q1, %Q2\n\t"
"mov %Q0, #0"
: "+&r" (res)
: "r" (m), "r" (n)
: "cc");
} else {
asm ( "umull %Q0, %R0, %Q2, %Q3\n\t"
"cmn %Q0, %Q2\n\t"
"adcs %R0, %R0, %R2\n\t"
"adc %Q0, %1, #0"
: "=&r" (res), "+&r" (tmp)
: "r" (m), "r" (n)
: "cc");
}
if (!(m & ((1ULL << 63) | (1ULL << 31)))) {
asm ( "umlal %R0, %Q0, %R1, %Q2\n\t"
"umlal %R0, %Q0, %Q1, %R2\n\t"
"mov %R0, #0\n\t"
"umlal %Q0, %R0, %R1, %R2"
: "+&r" (res)
: "r" (m), "r" (n)
: "cc");
} else {
asm ( "umlal %R0, %Q0, %R2, %Q3\n\t"
"umlal %R0, %1, %Q2, %R3\n\t"
"mov %R0, #0\n\t"
"adds %Q0, %1, %Q0\n\t"
"adc %R0, %R0, #0\n\t"
"umlal %Q0, %R0, %R2, %R3"
: "+&r" (res), "+&r" (tmp)
: "r" (m), "r" (n)
: "cc");
}
return res;
}
#define __arch_xprod_64 __arch_xprod_64
#include <asm-generic/div64.h>
#endif
#endif
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