commit 4bcefafb697c27501cda3cb6f1584df78d9011bc Author: Peter McGoron Date: Tue Feb 20 20:34:10 2024 -0500 xorshift diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..511a421 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +obj_dir \ No newline at end of file diff --git a/COPYING b/COPYING new file mode 100644 index 0000000..d54b426 --- /dev/null +++ b/COPYING @@ -0,0 +1,24 @@ +Copyright 2024 Peter McGoron + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions +are met: + +1. Redistributions of source code must retain the above copyright +notice, this list of conditions and the following disclaimer. + +2. Redistributions in binary form must reproduce the above copyright +notice, this list of conditions and the following disclaimer in the +documentation and/or other materials provided with the distribution. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +“AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED +TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR +PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF +LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING +NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..355baa5 --- /dev/null +++ b/Makefile @@ -0,0 +1,10 @@ +VERILATOR_FLAGS = --cc --exe -x-assign fast -Wall +VERILATOR_INPUT = xorshift.v xorshift.cpp + +obj_dir/Vxorshift: obj_dir/Vxorshift.mk obj_dir/Vxorshift.cpp \ + obj_dir/Vxorshift.h xorshift.cpp + cd obj_dir && make -f Vxorshift.mk && ./Vxorshift +obj_dir/Vxorshift.mk: $(VERILATOR_INPUT) + verilator $(VERILATOR_FLAGS) $(VERILATOR_INPUT) +clean: + rm -rf obj_dir diff --git a/README.rst b/README.rst new file mode 100644 index 0000000..40d8143 --- /dev/null +++ b/README.rst @@ -0,0 +1,12 @@ +------------ +verilog_rand +------------ + +Random number generators in verilog. BSD 2-clause. + +----------- +XORShift-64 +----------- + +XORShift-64 is a pseudo-RNG with a period of ``2^64-1``. +At 100 MHz it would take centuries before the RNG repeats. diff --git a/xorshift.cpp b/xorshift.cpp new file mode 100644 index 0000000..72c7925 --- /dev/null +++ b/xorshift.cpp @@ -0,0 +1,72 @@ +/* + * Copyright 2024 Peter McGoron + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +#include +#include +#include +#include +#include +#include "Vxorshift.h" + +Vxorshift *mod; + +static void run_clock() { + mod->clk = !mod->clk; + mod->eval(); + + mod->clk = !mod->clk; + mod->eval(); +} + +static uint64_t xorshift_64() { + static uint64_t state = 88172645463325252LL; + state ^= state << 13; + state ^= state >> 7; + return state ^= state << 17; +} + +int main(int argc, char **argv) { + Verilated::commandArgs(argc, argv); + mod = new Vxorshift; + + mod->clk = 0; + mod->eval(); + + for (int i = 0; i < 100000; i++) { + uint64_t correct = xorshift_64(); + run_clock(); + if (correct != mod->data) { + std::cout << i << " " << correct << "!=" << mod->data << std::endl; + } + } + + mod->final(); + + delete mod; + + return 0; +} diff --git a/xorshift.v b/xorshift.v new file mode 100644 index 0000000..1b57a19 --- /dev/null +++ b/xorshift.v @@ -0,0 +1,42 @@ +/* + * Copyright 2024 Peter McGoron + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED + * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. +*/ + +module xorshift ( + input clk, + output [64-1:0] data +); + +reg [64-1:0] state = 64'd88172645463325252; +assign data = state; + +always @ (posedge clk) begin +`define X_1 (state ^ (state << 13)) +`define X_2 (`X_1 ^ (`X_1 >> 7)) + state <= (`X_2 ^ (`X_2 << 17)); +end + +endmodule