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/********************************************************************
* Description: weighted_sum.c
* Weighted summer for HAL
*
* See the "Users Manual" at emc2/docs/Hal_Introduction.pdf
*
* This component is a "weighted summer". It has a (user specified)
* number of HAL_BIT input pins, and a HAL_S32 parameter corresponding
* to each bit input.
* There is one HAL_S32 output. The output value is the sum of the
* parameters for which the corresponding bit input is true.
*
* The default value for the parameters is 2^n, where n is the bit number.
* Default behavior results in a binary -> unsigned conversion.
*
* There is one array parameter at module load time, the number of bits for
* each weighted summer. There is a limit of 8 weighted summers, and each
* may have up to 16 input bits.
*
*********************************************************************
*
* Author: Stephen Wille Padnos (swpadnos AT sourceforge DOT net)
* Based on a work by John Kasunich
* License: GPL Version 2
* Created on: May 17, 2006
* System: Linux
*
* Copyright (c) 2006 All rights reserved.
*
********************************************************************/
#include "rtapi.h" /* RTAPI realtime OS API */
#include "rtapi_app.h" /* RTAPI realtime module decls */
#include "hal.h" /* HAL public API decls */
#define MAX_SUMMERS 8
#define MAX_SUM_BITS 16
/* module information */
MODULE_AUTHOR("Stephen Wille Padnos");
MODULE_DESCRIPTION("Weighted Summer for EMC HAL");
MODULE_LICENSE("GPL");
int wsum_sizes[MAX_SUMMERS] = { -1, -1, -1, -1, -1, -1, -1, -1 };
RTAPI_MP_ARRAY_INT(wsum_sizes, MAX_SUMMERS, "Sizes of up to 8 weighted summers");
/***********************************************************************
* STRUCTURES AND GLOBAL VARIABLES *
************************************************************************/
/* Data needed for each bit of a weighted summer */
typedef struct {
hal_bit_t *bit; /* pin: the input bit HAL pin */
hal_s32_t *weight; /* pin: the numeric weight of this pin */
} wsum_bit_t;
/* Base data for a weighted summer. */
typedef struct {
hal_s32_t *sum; /* output pin: the calculated sum */
hal_s32_t *offset; /* pin: offset for this summer */
hal_bit_t *hold; /* input pin: hold value if 1, update if 0 */
int num_bits; /* internal: How many bits are in this summer */
wsum_bit_t *bits; /* internal: pointer to the input bits and weights */
} wsum_t;
/* pointer to array of wsum structs in shmem */
static wsum_t *wsum_array;
static wsum_bit_t *wsum_bit_array;
/* other globals */
static int comp_id; /* component ID */
static int num_summers; /* number of summers created */
/***********************************************************************
* LOCAL FUNCTION DECLARATIONS *
************************************************************************/
static int export_wsum(int num, int num_bits, wsum_t *addr, wsum_bit_t *bitaddr);
static void process_wsums(void *arg, long period);
/***********************************************************************
* INIT AND EXIT CODE *
************************************************************************/
int rtapi_app_main(void)
{
int n, total_bits, retval;
total_bits = 0;
/* check that there's at least one valid summer requested */
for (n = 0; n < MAX_SUMMERS && wsum_sizes[n] != -1 ; n++) {
if ((wsum_sizes[n] > MAX_SUM_BITS) || (wsum_sizes[n]<1)) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: Invalid number of bits '%i' for summer %i\n",
wsum_sizes[n], n);
return -1;
} else {
num_summers++;
total_bits += wsum_sizes[n];
}
}
if (num_summers == 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: no summers specified\n");
return -1;
}
/* have good config info, connect to the HAL */
comp_id = hal_init("weighted_sum");
if (comp_id < 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: hal_init() failed\n");
return -1;
}
/* allocate shared memory for summer base info */
wsum_array = hal_malloc(num_summers * sizeof(wsum_t));
if (wsum_array == 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: hal_malloc() for summer array failed\n");
hal_exit(comp_id);
return -1;
}
/* allocate shared memory for summer bit arrays */
wsum_bit_array = hal_malloc(total_bits * sizeof(wsum_bit_t));
if (wsum_bit_array == 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: hal_malloc() for summer bit array failed\n");
hal_exit(comp_id);
return -1;
}
/* export pins/params for all summers */
total_bits = 0;
for (n = 0; n < num_summers; n++) {
/* export all vars */
retval = export_wsum(n, wsum_sizes[n], &(wsum_array[n]), &(wsum_bit_array[total_bits]));
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: group %d export failed\n", n);
hal_exit(comp_id);
return -1;
}
total_bits += wsum_array[n].num_bits;
}
/* export update function */
retval = hal_export_funct("process_wsums", process_wsums, wsum_array, 1, 0, comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: process_wsums funct export failed\n");
return -1;
}
rtapi_print_msg(RTAPI_MSG_INFO,
"WEIGHTED_SUM: installed %d weighted summers\n", num_summers);
hal_ready(comp_id);
return 0;
}
void rtapi_app_exit(void)
{
hal_exit(comp_id);
}
/***********************************************************************
* REALTIME DELAY FUNCTION *
************************************************************************/
/* The summer works by checking the input bits, and adding the
weight to the sum if the input is true.
*/
static void process_wsums(void *arg, long period)
{
wsum_t *wsums, *thissum;
int n, b, running_total;
/* point to filter group */
wsums = (wsum_t *)arg;
for (n=0 ; n<num_summers ; n++) {
thissum = &(wsums[n]);
if (*(thissum->hold)) continue;
else {
running_total = *(thissum->offset);
for (b=0 ; b<thissum->num_bits ; b++) {
if (*(thissum->bits[b].bit)) {
running_total += *(thissum->bits[b].weight);
}
}
}
*(thissum->sum) = running_total;
}
}
/***********************************************************************
* LOCAL FUNCTION DEFINITIONS *
************************************************************************/
static int export_wsum(int num, int num_bits, wsum_t *addr, wsum_bit_t *bitaddr)
{
int retval, i, w;
char buf[HAL_NAME_LEN+1], base[HAL_NAME_LEN+1];
rtapi_snprintf(base, sizeof(base), "wsum.%d", num);
/* export pin for offset (input) */
rtapi_snprintf(buf, sizeof(buf), "%s.offset", base);
retval = hal_pin_s32_new(buf, HAL_IO, &(addr->offset), comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: '%s' param export failed\n", buf);
return retval;
}
/* export pin for output sum */
rtapi_snprintf(buf, sizeof(buf), "%s.sum", base);
retval = hal_pin_s32_new(buf, HAL_OUT, &(addr->sum), comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: '%s' pin export failed\n", buf);
return retval;
}
/* export pin for update hold */
rtapi_snprintf(buf, sizeof(buf), "%s.hold", base);
retval = hal_pin_bit_new(buf, HAL_IN, &(addr->hold), comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: '%s' pin export failed\n", buf);
return retval;
}
addr->bits = bitaddr;
addr->num_bits = num_bits;
/* export the input bits and weight parameters, and set the default weights */
w = 1;
for (i=0;i<num_bits;i++) {
rtapi_snprintf(buf, sizeof(buf), "%s.bit.%d.in", base, i);
retval = hal_pin_bit_new(buf, HAL_IN, &(addr->bits[i].bit), comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: '%s' pin export failed\n", buf);
return retval;
}
rtapi_snprintf(buf, sizeof(buf), "%s.bit.%d.weight", base, i);
retval = hal_pin_s32_new(buf, HAL_IO, &(addr->bits[i].weight), comp_id);
if (retval != 0) {
rtapi_print_msg(RTAPI_MSG_ERR,
"WEIGHTED_SUM: ERROR: '%s' param export failed\n", buf);
return retval;
}
*(addr->bits[i].weight) = w;
w <<= 1;
}
/* set initial parameter and pin values */
*(addr->offset) = 0;
*(addr->sum) = 0;
return 0;
}