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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 10:05:51 +0000 |
commit | 5d1646d90e1f2cceb9f0828f4b28318cd0ec7744 (patch) | |
tree | a94efe259b9009378be6d90eb30d2b019d95c194 /arch/arm/include/asm/div64.h | |
parent | Initial commit. (diff) | |
download | linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.tar.xz linux-5d1646d90e1f2cceb9f0828f4b28318cd0ec7744.zip |
Adding upstream version 5.10.209.upstream/5.10.209
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | arch/arm/include/asm/div64.h | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/arch/arm/include/asm/div64.h b/arch/arm/include/asm/div64.h new file mode 100644 index 000000000..898e9c78a --- /dev/null +++ b/arch/arm/include/asm/div64.h @@ -0,0 +1,131 @@ +/* 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). + */ + +#ifdef __ARMEB__ +#define __xh "r0" +#define __xl "r1" +#else +#define __xl "r0" +#define __xh "r1" +#endif + +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"); + register unsigned int __rem asm(__xh); + asm( __asmeq("%0", __xh) + __asmeq("%1", "r2") + __asmeq("%2", "r0") + __asmeq("%3", "r4") + "bl __do_div64" + : "=r" (__rem), "=r" (__res) + : "r" (__n), "r" (__base) + : "ip", "lr", "cc"); + *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 |