Hi,
I'm getting an Compiler Error, but cannot understand why.
Does maybe somebody has an Idea what i've coded wrong?
When i'm removing the Calculation included within if Statement it compiles without Errors.
Compiler Error:
exit status 1
unable to find a register to spill in class 'POINTER_REGS'
When compiling following Code:
const int cAxisCount =2; //Total Count of used Axis
double dSpeed[cAxisCount] ={10,10};
double dPositionCommand[cAxisCount],dPositionSetpoint[cAxisCount];
void setup()
{}
void loop()
{
//Calculate Speed
for(int i=0; i<cAxisCount; i++)
{
//Speed
if(dPositionCommand[i] > dPositionSetpoint[i] + dSpeed[i])
dPositionSetpoint[i] = dPositionSetpoint[i] + dSpeed[i];
else if(dPositionCommand[i] < dPositionSetpoint[i] - dSpeed[i])
dPositionSetpoint[i] = dPositionSetpoint[i] - dSpeed[i];
else
dPositionSetpoint[i] = dPositionCommand[i];
}
}
You can make "i" global:
const int cAxisCount = 2; //Total Count of used Axis
double dSpeed[cAxisCount] = {10.0, 10.0};
double dPositionCommand[cAxisCount];
double dPositionSetpoint[cAxisCount];
int i;
void setup()
{
}
void loop()
{
//Calculate Speed
for ( i = 0; i < cAxisCount; i++)
{
//Speed
if (dPositionCommand[i] > dPositionSetpoint[i] + dSpeed[i])
dPositionSetpoint[i] = dPositionSetpoint[i] + dSpeed[i];
else if (dPositionCommand[i] < dPositionSetpoint[i] - dSpeed[i])
dPositionSetpoint[i] = dPositionSetpoint[i] - dSpeed[i];
else
{
dPositionSetpoint[i] = dPositionCommand[i];
}
}
}
IDE 1.6.5
I can reproduce that with 1.6.7.
How does making "i" global work? (which it does)
maxx8888:
Does maybe somebody has an Idea what i've coded wrong?
Nothing. Compiler errors are rare, but you found one. 
By typing things on the keyboard? I don't know... also this works:
void loop()
{
static int i;
//Calculate Speed
for ( i = 0; i < cAxisCount; i++)
@maxx8888, code organized like that cries out for a struct / class.
In the meantime, some basic reduction overcomes the problem...
const int cAxisCount =2; //Total Count of used Axis
double dSpeed[cAxisCount] ={10,10};
double dPositionCommand[cAxisCount],dPositionSetpoint[cAxisCount];
void setup()
{}
void loop()
{
//Calculate Speed
for(int i=0; i<cAxisCount; i++)
{
double ps;
ps = dPositionSetpoint[i];
//Speed
if(dPositionCommand[i] > ps + dSpeed[i])
ps = ps + dSpeed[i];
else if(dPositionCommand[i] < ps - dSpeed[i])
ps = ps - dSpeed[i];
else
ps = dPositionCommand[i];
dPositionSetpoint[i] = ps;
}
}
I suspect a Pascal "with" would eliminate the problem but the language lacks it.
Fully reduced...
const int cAxisCount =2; //Total Count of used Axis
double dSpeed[cAxisCount] ={10,10};
double dPositionCommand[cAxisCount],dPositionSetpoint[cAxisCount];
void setup()
{}
void loop()
{
//Calculate Speed
for(int i=0; i<cAxisCount; i++)
{
double pc;
double ps;
double s;
pc = dPositionCommand[i];
ps = dPositionSetpoint[i];
s = dSpeed[i];
//Speed
if(pc > ps + s)
ps = ps + s;
else if(pc < ps - s)
ps = ps - s;
else
ps = pc;
dPositionSetpoint[i] = ps;
}
}
Wow :o.
Thanks for all the answers!
Ok, then it is really a compiler Bug and i need todo one of the proposed workarounds.
I'm trying to control 2 DC Motors with the Codepart i've posted.
In order to keep fast response on the Motors i'm trying to run the full Arduino loop in less than 1msec.
I tried to avoid thinks like Variable Declaration within For Loops. I thought this would make things slower.
Or is this a wrong assumption?
Thererfore the static "i" Variable would even speed things up, right?
Hmm, just need to consider Serial Communication and Encoder Interrupts, which are also using i as variable in for Loops...
maxx8888:
Thererfore the static "i" Variable would even speed things up, right?
Wrong. Automatic variables are either the same performance as static variables or better performance.