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109 lines (93 loc) · 3.59 KB
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/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2015 Daniel Campora
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include <stdbool.h>
#include "py/obj.h"
#include "inc/hw_types.h"
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "rom_map.h"
#include "pybrtc.h"
#include "simplelink.h"
#include "modnetwork.h"
#include "modwlan.h"
#include "random.h"
#include "debug.h"
/******************************************************************************
* LOCAL TYPES
******************************************************************************/
typedef union _rng_id_t {
uint32_t id32;
uint16_t id16[3];
uint8_t id8[6];
} rng_id_t;
/******************************************************************************
* LOCAL VARIABLES
******************************************************************************/
static uint32_t s_seed;
/******************************************************************************
* LOCAL FUNCTION DECLARATIONS
******************************************************************************/
STATIC uint32_t lfsr (uint32_t input);
/******************************************************************************
* PRIVATE FUNCTIONS
******************************************************************************/
STATIC uint32_t lfsr (uint32_t input) {
assert( input != 0 );
return (input >> 1) ^ (-(input & 0x01) & 0x00E10000);
}
/******************************************************************************/
// Micro Python bindings;
STATIC mp_obj_t machine_rng_get(void) {
return mp_obj_new_int(rng_get());
}
MP_DEFINE_CONST_FUN_OBJ_0(machine_rng_get_obj, machine_rng_get);
/******************************************************************************
* PUBLIC FUNCTIONS
******************************************************************************/
void rng_init0 (void) {
rng_id_t juggler;
uint32_t seconds;
uint16_t mseconds;
// get the seconds and the milliseconds from the RTC
pyb_rtc_get_time(&seconds, &mseconds);
wlan_get_mac (juggler.id8);
// flatten the 48-bit board identification to 24 bits
juggler.id16[0] ^= juggler.id16[2];
juggler.id8[0] ^= juggler.id8[3];
juggler.id8[1] ^= juggler.id8[4];
juggler.id8[2] ^= juggler.id8[5];
s_seed = juggler.id32 & 0x00FFFFFF;
s_seed += (seconds & 0x000FFFFF) + mseconds;
// the seed must not be zero
if (s_seed == 0) {
s_seed = 1;
}
}
uint32_t rng_get (void) {
s_seed = lfsr( s_seed );
return s_seed;
}