using both interrupts and firmware

[Xifos]

Hi,

I am trying to use the 6 fixed interrupts to just change the background color.
I am using sdcc, but i wrote an asm function to do that.
I put a jp myfunction at 038h, di at the beginning, and  at the end of my function, i am jumping at B942h (winape as 6128).
In this function i am trying to change the color folowing a counter.

Here's my algorithm :
di
save registers on stack
test if vbl is set
if vbl counter set it as 0
test counter, set color
inc counter
restore registers
jp B942h
ret

Everything works fine, colors are changed at the right time.
But if i do a firmware call in the main program, for exemple a keyboard vector call (call BB1Eh), it goes wrong, as if the counter was lost.

I know it's not good to use firmware, but in that case i would like to undertsand what's happening.
Are there just 6 interrupts per vbl doing rst 038h, or can there be more ?

I know i'am not good at using interrupts neither at writing in english !

[AMSDOS]

Think you'll need to Enable Interrupts before using the Firmware.

[arnoldemu]

don't fight the firmware.

try something like this:

Code Select Expand



typedef  void (*ticker_fn)(void);

void InstallFastTicker(void *pDataBlock, ticker_fn fn)
{
    __asm
        ld hl,#_pDataBlock ;; block
        ld b,#0x080        ;; class
        ld c,#0x0ff        ;; rom select
        ld de,#_fn        ;; function
        call 0x0bce3    ;;kl_new_fast_ticker
    __endasm
}

void DelFastTicker(void *pDataBlock)
{
    __asm
    {
        ld hl,#_pDataBlock
        call 0x0bce6    ;;kl_del_fast_ticker
    }
}

void MyFastTicker()
{
    // here...

}


// not sure of the size of the block
unsigned char MyFastTickerBlock[32];

void main()
{
    InstallFastTicker(MyFastTickerBlock, MyFastTicker);
}



Code is not tested!!

[Xifos]

Thanks for the replies.


> AMSDOS
You 're saying , put ei before the part where i jump to B941 ?
no changes
The fact is that everything works fine if i don't use system vectors !

>Arnoldemu
When doing this, does not my routine need to be between 4000h and c000h ?
I'am not good at doing relocatable code ! (i know i know)


But i'll try, probably this week end...

[arnoldemu]

Yes probably between 4000 and 8000. It may work from Rom but the kernel b l rock must be in ram. Try it.

[AMSDOS]

Thanks for the replies.


> AMSDOS
You 're saying , put ei before the part where i jump to B941 ?
no changes
The fact is that everything works fine if i don't use system vectors !

Hmmm, yes, I think this maybe a bit out of my league.    My feeling was you cannot use Firmware routines like &BB1E while Interrupts are disabled.

[Xifos]

I finally did it, following Arnoldemu's way.
And after seeing this : source/intpos.asm

One thing is that i have to forget trying to detect if i'm in the vbl interrupt or no.
I am just reseting the counter after 5.
The other annoying thing is that the fast ticker routine and it's block have to be between 4000 and 8000.
And i don't understand what exactly means this part :
ld b,#0x080        ;; class
ld c,#0x0ff        ;; rom select
The good things is that that's working, even with firmware routines calls, even without vbl synchro in the main program, but i find that the interrupts locations are not equal.

Thanks for your help !!! 

[arnoldemu]

I finally did it, following Arnoldemu's way.
And after seeing this : source/intpos.asm

One thing is that i have to forget trying to detect if i'm in the vbl interrupt or no.
I am just reseting the counter after 5.
The other annoying thing is that the fast ticker routine and it's block have to be between 4000 and 8000.
And i don't understand what exactly means this part :
ld b,#0x080        ;; class
ld c,#0x0ff        ;; rom select
The good things is that that's working, even with firmware routines calls, even without vbl synchro in the main program, but i find that the interrupts locations are not equal.

Thanks for your help !!! 

The class and Rom select are described in the soft968 manual.
In this programming part of the forum I posted some assembly code which gives exact interrupt position for mode and colour splits. I use a special type of fast ticker firmware interrupt to make this. I had to disassemble the Cpc firmware to discover the way to do this.

When I have time I will post a full c example of the code I gave in my post above.

[Xifos]

Ah, i understand now.

I could put my fast ticker routine at a far address, but it seems that the fast ticker block must stay between 4000 and c000.
The locations of the code relative to the interrupts are better now.
(i am a good student, isn'it ?)