Re: A89: Keypresses slow down programs

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Re: A89: Keypresses slow down programs


Hi!

| My tip is to always disable all interrupts that you don't use.
| If you don't use any, just disable them all with trap #1, if you use some,
like
| with grayscale or something, change all the rest to a dummy interrupt
which just
| rte:s
| Then you are always shure that the OS doesn't steal valuable cycles at any
time.

OK; I changed interrupt 2 (0x68) to rte.  It gives me an ILLEGAL INSTRUCTION
error every time I press a key other than ON (which triggers the interrupt).
What am I doing wrong?  My C code for Interrupts.h is this:

// Interrupt Handling

void *IntGetFunctionAddress (void **IntAddress);
void IntSetFunctionAddress (void **IntAddress, void *FunctionAddress);
void *IntDisable (void **IntAddress);
void IntEnable (void **IntAddress, void *DisableResult);

extern void *__dint;
asm(" xdef __dint
__dint: rte ");

void *IntGetFunctionAddress (void **IntAddress)
{
 return (*IntAddress);
}

void IntSetFunctionAddress (void **IntAddress, void *FunctionAddress)
{
 unsigned char Protection;
 Protection = *((unsigned char*)(0x600001));
 *((unsigned char*)(0x600001)) = Protection & (~(0x04));  // reset bit 2
 *IntAddress = FunctionAddress;
 *((unsigned char*)(0x600001)) = Protection;
}

void *IntDisable (void **IntAddress)
{
 void *Addr;
 Addr = IntGetFunctionAddress (IntAddress);
 IntSetFunctionAddress (IntAddress, __dint);
 return Addr;
}

void IntEnable (void **IntAddress, void *DisableResult)
{
 IntSetFunctionAddress (IntAddress, DisableResult);
}

// end of file

I would greatly appreciate any help from anybody.  Those two lines are my
first code segment in ASM. :-)  BTW:  If I insert NOP before RTE, I get an
address error instead.  Maybe that helps.  I also tried declaring '__dint'
as a void function, but then the program displayed an address error every
time I ran it.

I call IntDisable ((void*)(0x68)) at the beginning, after initializing
grayscale.  At the end I call IntEnable, to which I have to pass the result
of IntDisable.  I think you should be able to figure out the rest.

When I run my program with disabled auto-int 2, grayscale (which uses
auto-int 1) gets messed up pretty badly.  Maybe that's another hint.

Bye,
Sebastian
References: