beremiz

use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

2019-01-06, Andrey Skvortsov
68f4f2d4516b
use pregenerated CRC32 lookup tables for retain on Win32 and GNU/Linux

This code could be possible reused on low-end targets with limited RAM.

code to generate lookup table:
[---------------------------------------------------------------------]

/* CRC lookup table and initial state. */
uint32_t crc32_table[256];

/* Generate CRC32 lookup table. */
void GenerateCRC32Table(void)
{
unsigned int i, j;
/* Use CRC-32-IEEE 802.3 polynomial 0x04C11DB7 (bit reflected). */
uint32_t poly = 0xEDB88320;

for (i = 0; i <= 0xFF; i++)
{
uint32_t c = i;
for (j = 0 ; j < 8 ; j++)
c = (c & 1) ? (c >> 1 ) ^ poly : (c >> 1);
crc32_table[i] = c;
}
}

void main(void)
{
GenerateCRC32Table();
int j=0;
for(int i=0; i<256; i++) {
printf("0x%08X, ", crc32_table[i]);
if (++j >= 8) {
j = 0;
printf("\n");
}
}
}
[---------------------------------------------------------------------]
/**
* Head of code common to all C targets
**/
#include "beremiz.h"
#include <string.h>
/*
* Prototypes of functions provided by generated C softPLC
**/
void config_run__(unsigned long tick);
void config_init__(void);
/*
* Prototypes of functions provided by generated target C code
* */
long long AtomicCompareExchange64(long long*, long long, long long);
void __init_debug(void);
void __cleanup_debug(void);
/*void __retrieve_debug(void);*/
void __publish_debug(void);
/*
* Variables used by generated C softPLC and plugins
**/
IEC_TIME __CURRENT_TIME;
IEC_BOOL __DEBUG = 0;
unsigned long __tick = 0;
char *PLC_ID = NULL;
/*
* Variable generated by C softPLC and plugins
**/
extern unsigned long greatest_tick_count__;
/* Help to quit cleanly when init fail at a certain level */
static int init_level = 0;
/* Prototype for Logging to help spotting errors at init */
int LogMessage(uint8_t level, char* buf, uint32_t size);
/*
* Prototypes of functions exported by plugins
**/
%(calls_prototypes)s
/*
* Retrieve input variables, run PLC and publish output variables
**/
void __run(void)
{
__tick++;
if (greatest_tick_count__)
__tick %%= greatest_tick_count__;
%(retrieve_calls)s
/*__retrieve_debug();*/
config_run__(__tick);
__publish_debug();
%(publish_calls)s
}
/*
* Initialize variables according to PLC's default values,
* and then init plugins with that values
**/
int __init(int argc,char **argv)
{
int res = 0;
init_level = 0;
/* Effective tick time with 1ms default value */
if(!common_ticktime__)
common_ticktime__ = 1000000;
config_init__();
__init_debug();
%(init_calls)s
return res;
}
/*
* Calls plugin cleanup proc.
**/
void __cleanup(void)
{
%(cleanup_calls)s
__cleanup_debug();
}
void PLC_GetTime(IEC_TIME *CURRENT_TIME);
void PLC_SetTimer(unsigned long long next, unsigned long long period);