98 lines
2.4 KiB
C
98 lines
2.4 KiB
C
///////////////////////////////////////////////////////////////////////////////////
|
|
//-------------------------------------------------------------------------------//
|
|
//-------------------------------------------------------------------------------//
|
|
//-----------H----H--X----X-----CCCCC----22222----0000-----0000------11----------//
|
|
//----------H----H----X-X-----C--------------2---0----0---0----0--1--1-----------//
|
|
//---------HHHHHH-----X------C----------22222---0----0---0----0-----1------------//
|
|
//--------H----H----X--X----C----------2-------0----0---0----0-----1-------------//
|
|
//-------H----H---X-----X---CCCCC-----222222----0000-----0000----1111------------//
|
|
//-------------------------------------------------------------------------------//
|
|
//----------------------------------------------------- http://hxc2001.free.fr --//
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
// File : rand_gen.c
|
|
// Contains: random generators
|
|
//
|
|
// This file is part of rf-tools.
|
|
//
|
|
// Written by: Jean-François DEL NERO
|
|
//
|
|
// Copyright (C) 2022 Jean-François DEL NERO
|
|
//
|
|
// You are free to do what you want with this code.
|
|
// A credit is always appreciated if you use it into your product :)
|
|
//
|
|
// Change History (most recent first):
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#include <stdint.h>
|
|
|
|
#include "rand_gen.h"
|
|
|
|
uint8_t rand_gen_get_next_byte(rand_gen_state *state)
|
|
{
|
|
uint8_t retbyte;
|
|
uint32_t seed;
|
|
uint32_t byte_number;
|
|
|
|
seed = state->current_seed;
|
|
byte_number = state->byte_number;
|
|
|
|
if( byte_number > 3 )
|
|
{
|
|
byte_number = 0x00;
|
|
|
|
/* Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs" */
|
|
seed ^= seed << 13;
|
|
seed ^= seed >> 17;
|
|
seed ^= seed << 5;
|
|
|
|
state->current_seed = seed;
|
|
}
|
|
|
|
retbyte = ( seed >> ( (3 - byte_number) << 3) ) & 0xFF;
|
|
|
|
byte_number++;
|
|
|
|
state->byte_number = byte_number;
|
|
|
|
return retbyte;
|
|
}
|
|
|
|
uint32_t rand_gen_get_next_word(rand_gen_state *state)
|
|
{
|
|
uint32_t retword;
|
|
uint32_t seed;
|
|
|
|
seed = state->current_seed;
|
|
|
|
retword = seed;
|
|
|
|
/* Algorithm "xor" from p. 4 of Marsaglia, "Xorshift RNGs" */
|
|
seed ^= seed << 13;
|
|
seed ^= seed >> 17;
|
|
seed ^= seed << 5;
|
|
|
|
state->byte_number = 0x00;
|
|
state->current_seed = seed;
|
|
|
|
return retword;
|
|
}
|
|
|
|
void rand_gen_init(rand_gen_state *state, uint32_t seed )
|
|
{
|
|
if(!state)
|
|
return;
|
|
|
|
if( seed )
|
|
{
|
|
state->current_seed = seed;
|
|
state->byte_number = 0;
|
|
}
|
|
else
|
|
{
|
|
state->current_seed = 0x12E6C816;
|
|
state->byte_number = 0;
|
|
}
|
|
}
|
|
|