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54 lines
1.3 KiB
54 lines
1.3 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/export.h> |
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#include "libgcc.h" |
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/* |
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* GCC 7 & older can suboptimally generate __multi3 calls for mips64r6, so for |
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* that specific case only we implement that intrinsic here. |
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* |
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* See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82981 |
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*/ |
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#if defined(CONFIG_64BIT) && defined(CONFIG_CPU_MIPSR6) && (__GNUC__ < 8) |
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/* multiply 64-bit values, low 64-bits returned */ |
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static inline long long notrace dmulu(long long a, long long b) |
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{ |
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long long res; |
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asm ("dmulu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); |
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return res; |
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} |
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/* multiply 64-bit unsigned values, high 64-bits of 128-bit result returned */ |
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static inline long long notrace dmuhu(long long a, long long b) |
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{ |
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long long res; |
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asm ("dmuhu %0,%1,%2" : "=r" (res) : "r" (a), "r" (b)); |
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return res; |
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} |
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/* multiply 128-bit values, low 128-bits returned */ |
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ti_type notrace __multi3(ti_type a, ti_type b) |
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{ |
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TWunion res, aa, bb; |
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aa.ti = a; |
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bb.ti = b; |
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/* |
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* a * b = (a.lo * b.lo) |
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* + 2^64 * (a.hi * b.lo + a.lo * b.hi) |
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* [+ 2^128 * (a.hi * b.hi)] |
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*/ |
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res.s.low = dmulu(aa.s.low, bb.s.low); |
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res.s.high = dmuhu(aa.s.low, bb.s.low); |
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res.s.high += dmulu(aa.s.high, bb.s.low); |
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res.s.high += dmulu(aa.s.low, bb.s.high); |
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return res.ti; |
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} |
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EXPORT_SYMBOL(__multi3); |
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#endif /* 64BIT && CPU_MIPSR6 && GCC7 */
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