Drazen Urch
7bd1550195
* Checkpoint * cpu cycle ffi * Rename * mixnode feature * Bundle libcpucycles
40 lines
820 B
C
40 lines
820 B
C
// version 20230105
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// public domain
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// djb
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// adapted from supercop/cpucycles/riscv.c
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// which has code from djb and Romain Dolbeau
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#include "cpucycles_internal.h"
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#ifndef __riscv_xlen
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#error this code is only for riscv platforms
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#endif
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#if __riscv_xlen != 32
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#error this code is only for riscv32 platforms
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#endif
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long long ticks(void)
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{
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unsigned int low, high, newhigh;
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unsigned long long result;
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asm volatile( "start%=:\n"
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"rdcycleh %0\n"
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"rdcycle %1\n"
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"rdcycleh %2\n"
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"bne %0, %2, start%=\n"
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: "=r"(high), "=r"(low), "=r"(newhigh));
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result = high;
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result <<= 32;
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result |= low;
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return result;
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}
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long long ticks_setup(void)
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{
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if (!cpucycles_works(ticks)) return cpucycles_SKIP;
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return cpucycles_CYCLECOUNTER;
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}
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