linse/sics
0
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

use PSI IEEE float code

Browse Source 
r3057 | dcl | 2011-02-16 16:29:35 +1100 (Wed, 16 Feb 2011) | 1 line
This commit is contained in:
Douglas Clowes
2011-02-16 16:29:35 +11:00
parent 69c79771cb
commit 18a57956b1
1 changed files with 80 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

93
site_ansto/hardsup/sct_modbusprot.c
View File

@@ -6,11 +6,71 @@
#include <ascon.i>
#include <dynstring.h>
#include <stdbool.h>
#include <math.h>
static int dbgprintf(char* fmtstr, ...);
static int dbgprintx(const char* msg, const unsigned char* cp, int blen);
static unsigned int debug_modbus = 1;
/*-------------------------------------------------------------------------*/
/* IEEE code copied from psi/modbus.c */
static void double2ieee(double input, char ieee[4]) {
/* convert double to IEEE 32 bit floating number (denormalized numbers are considered as zero) */
long mantissa;
int exponent;
if (input == 0) {
ieee[0]= 0;
ieee[1]= 0;
ieee[2]= 0;
ieee[3]= 0;
} else {
mantissa = 0x1000000 * (frexp(fabs(input), &exponent));
exponent = exponent - 1 + 127;
if (exponent < 0) {
exponent = 0;
} else if (exponent > 0xFE) {
exponent = 0xFE;
}
if (input < 0) {
ieee[0] = 0x80 | (exponent >> 1);
} else {
ieee[0] = exponent >> 1;
}
ieee[1] = (exponent & 1) << 7 | ((mantissa & 0x7F0000) >> 16);
ieee[2] = (mantissa & 0xFF00) >> 8;
ieee[3] = mantissa & 0xFF;
}
return;
}
/*-------------------------------------------------------------------------*/
static double ieee2double(char ieee[4]) {
/* IEEE 32 bit floating number to double (denormalized numbers are considered as zero) */
long mantissa;
double output;
int exponent;
mantissa = ((ieee[1] << 16) & 0x7FFFFF)
| ((ieee[2] << 8) & 0xFF00)
| ((ieee[3] ) & 0xFF);
exponent = (ieee[0] & 0x7F) * 2 + ((ieee[1] >> 7) & 1); /* raw exponent */
if (exponent == 0 && mantissa == 0) {
return 0.0;
}
output = ldexp(mantissa, -23) + 1.0;
if (ieee[0] & 0x80) {
output = -output;
}
return output * ldexp(1, exponent - 127);
}
/*-------------------------------------------------------------------------*/
/** @brief encode modbus request
* TODO: clean me up
*/
@@ -71,19 +131,22 @@ int ModbusWriteStart(Ascon *a) {
if (cmd == 16) { /* write registers */
buff = endp + 1;
if (do_float) {
union { unsigned char v[4]; float val; } u;
u.val = strtof(buff, &endp);
struct { char v[4]; } ieee; /* big endian */
double val = strtod(buff, &endp);
if (endp == buff) {
dbgprintf("modbus-er: Bad value: %f from %s\n", u.val, buff);
dbgprintf("modbus-er: Bad value: %f from %s\n", val, buff);
a->state = AsconIdle;
AsconError(a, "Bad value", 0);
return 0;
}
double2ieee(val, ieee.v);
dbgprintf("strtod:%f\n", val);
dbgprintx("double2ieee", (unsigned char*)ieee.v, 4);
temp[idx++] = 4; /* byte count */
temp[idx++] = u.v[1];
temp[idx++] = u.v[0];
temp[idx++] = u.v[3];
temp[idx++] = u.v[2];
temp[idx++] = ieee.v[2]; /* watlow RUI specific byte ordering */
temp[idx++] = ieee.v[3];
temp[idx++] = ieee.v[0];
temp[idx++] = ieee.v[1];
} else {
unsigned int val;
val = strtoul(buff, &endp, 10);
@@ -137,12 +200,16 @@ int ModbusReading(Ascon *a) {
rlen = snprintf(temp, 64, "%d", (((unsigned int)cp[9]) << 8) + (unsigned int)cp[10]);
}
else if (cp[7] == 3 && cp[8] == 4) {
union { unsigned char v[4]; float val; } u;
u.v[1] = cp[9];
u.v[0] = cp[10];
u.v[3] = cp[11];
u.v[2] = cp[12];
rlen = snprintf(temp, 64, "%g", u.val);
struct { char v[4]; } ieee;
double val;
ieee.v[2] = cp[9]; /* watlow RUI specific byte ordering */
ieee.v[3] = cp[10];
ieee.v[0] = cp[11];
ieee.v[1] = cp[12];
val = ieee2double(ieee.v);
dbgprintx("rawhex", (unsigned char*)&cp[9], 4);
dbgprintf("ieee2double:%f\n", val);
rlen = snprintf(temp, 64, "%g", val);
}
else if (cp[7] == 16 && cp[11] == 1) {
rlen = snprintf(temp, 64, "OK int");