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#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include "types.h"
#include "getter.h"
#include "instset.h"
#include "memory.h"
#include "evolver.h"
static boolean g_is_init;
static uint32 g_last_changed_address;
static uint32 g_calls_on_last_cycle;
static uint32 g_state[4];
void _sal_evo_init(void)
{
/*
* Start up the evolver module. We simply set the 128 bits into a random
* state by calling 'rand()'.
*/
assert(!g_is_init);
srand((uint32)time(NULL));
g_state[0] = rand();
g_state[1] = rand();
g_state[2] = rand();
g_state[3] = rand();
g_is_init = TRUE;
}
void _sal_evo_quit(void)
{
/*
* Quit the evolver module. Reset everything back to zero.
*/
assert(g_is_init);
g_is_init = FALSE;
g_last_changed_address = 0;
g_calls_on_last_cycle = 0;
memset(g_state, 0, sizeof(uint32) * 4);
}
void _sal_evo_load_from(FILE *file)
{
/*
* Load evolver state from a binary file.
*/
assert(!g_is_init);
assert(file);
fread(&g_is_init, sizeof(boolean), 1, file);
fread(&g_last_changed_address, sizeof(uint32), 1, file);
fread(&g_calls_on_last_cycle, sizeof(uint32), 1, file);
fread(&g_state, sizeof(uint32), 4, file);
}
void _sal_evo_save_into(FILE *file)
{
/*
* Save evolver state into a binary file.
*/
assert(g_is_init);
assert(file);
fwrite(&g_is_init, sizeof(boolean), 1, file);
fwrite(&g_last_changed_address, sizeof(uint32), 1, file);
fwrite(&g_calls_on_last_cycle, sizeof(uint32), 1, file);
fwrite(&g_state, sizeof(uint32), 4, file);
}
/*
* Getter methods for the evolver module.
*/
UINT32_GETTER(evo, last_changed_address)
UINT32_GETTER(evo, calls_on_last_cycle)
uint32 sal_evo_get_state(uint8 state_index)
{
/*
* Get part of the evolver's internal state (32 bits of 128 total bits) as
* an unsigned int.
*/
assert(g_is_init);
assert(state_index < 4);
return g_state[state_index];
}
static uint32 generate_random_number(void)
{
/*
* Generate a single 32 bit random number. This module makes use of the
* XOR-Shift pseudo-rng. We use XOR-Shift because it's extremely lightweight
* and fast, while providing quite good results. Find more info about it at:
* https://en.wikipedia.org/wiki/Xorshift
*/
uint32 tmp1;
uint32 tmp2;
assert(g_is_init);
tmp2 = g_state[3];
tmp2 ^= tmp2 << 11;
tmp2 ^= tmp2 >> 8;
g_state[3] = g_state[2];
g_state[2] = g_state[1];
g_state[1] = tmp1 = g_state[0];
tmp2 ^= tmp1;
tmp2 ^= tmp1 >> 19;
g_state[0] = tmp2;
g_calls_on_last_cycle++;
return tmp2;
}
void _sal_evo_randomize_at(uint32 address)
{
/*
* Place a random instruction into a given address.
*/
uint8 inst;
assert(g_is_init);
assert(sal_mem_is_address_valid(address));
inst = generate_random_number() % INST_COUNT;
g_last_changed_address = address;
sal_mem_set_inst(address, inst);
}
void _sal_evo_cycle(void)
{
/*
* During each simulation cycle, a random 32 bit integer is generated. If
* this integer represents a 'valid' address in memory (new_rand < mem_size),
* this address becomes hit by a cosmic ray (randomized). This simple
* mutation scheme is enough to drive evolution in Salis.
*/
uint32 address;
assert(g_is_init);
g_calls_on_last_cycle = 0;
address = generate_random_number();
if (sal_mem_is_address_valid(address)) {
_sal_evo_randomize_at(address);
}
}
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