looks like 'interrupt' macro does not work properly.
__attribute__((interrupt(X))) forces gcc to save _all_ used registers, then
issue 'reti' .
As long as gcc uses r12-r15 and does not save it, I think the function just
missing the attribute . Check this way.
~d
On Tuesday 13 May 2003 15:43, Mark Stokes wrote:
> At the cost of more of my hair, I have found another possible bug in the
> compiler.
> When using Timer_A IRQ, the compiler doesn't save any registers it might
> use for calculations. Here is a listing of my Timer_A ISR:
> 00001b76 <TimerACC0IRQ>:
>
> volatile unsigned long int lastcc;
> /***********************************************************************
> *******
> Timer_A Capture Compare Interrupt Service Routine (CCIFG0):
> ************************************************************************
> ******/
> interrupt (TIMERA0_VECTOR) TimerACC0IRQ( void )
> {
>
> if ( TACTL & TAIFG ) // Check for overflow
> 1b76: 92 b3 60 01 bit #1, &0x0160 ;r3 As==01
> 1b7a: 13 24 jz $+40 ;abs 0x1ba2
> {
> count8m = 65535u - lastcc + TACCR0;
> 1b7c: 1f 42 72 01 mov &0x0172,r15 ;0x0172
> 1b80: 0e 4f mov r15, r14 ;
> 1b82: 0f 43 clr r15 ;
> 1b84: 1c 42 04 02 mov &0x0204,r12 ;0x0204
> 1b88: 1d 42 06 02 mov &0x0206,r13 ;0x0206
> 1b8c: 0e 8c sub r12, r14 ;
> 1b8e: 0f 7d subc r13, r15 ;
> 1b90: 3e 53 add #-1, r14 ;r3 As==11
> 1b92: 0f 63 adc r15 ;
> 1b94: 82 4e 00 02 mov r14, &0x0200 ;
> 1b98: 82 4f 02 02 mov r15, &0x0202 ;
> TACTL &= ~TAIFG; // Clear Timer_A Interrupt flag
> (overflow bit)
> 1b9c: 92 c3 60 01 bic #1, &0x0160 ;r3 As==01
> 1ba0: 0e 3c jmp $+30 ;abs 0x1bbe
> }
> else
> count8m = TACCR0 - lastcc;
> 1ba2: 1f 42 72 01 mov &0x0172,r15 ;0x0172
> 1ba6: 0e 4f mov r15, r14 ;
> 1ba8: 0f 43 clr r15 ;
> 1baa: 1c 42 04 02 mov &0x0204,r12 ;0x0204
> 1bae: 1d 42 06 02 mov &0x0206,r13 ;0x0206
> 1bb2: 0e 8c sub r12, r14 ;
> 1bb4: 0f 7d subc r13, r15 ;
> 1bb6: 82 4e 00 02 mov r14, &0x0200 ;
> 1bba: 82 4f 02 02 mov r15, &0x0202 ;
> lastcc = TACCR0;
> 1bbe: 1f 42 72 01 mov &0x0172,r15 ;0x0172
> 1bc2: 0e 4f mov r15, r14 ;
> 1bc4: 0f 43 clr r15 ;
> 1bc6: 82 4e 04 02 mov r14, &0x0204 ;
> 1bca: 82 4f 06 02 mov r15, &0x0206 ;
>
> TACCTL0 &= ~CCIFG; // Clear CCIFG Interrupt flag
> 1bce: 92 c3 62 01 bic #1, &0x0162 ;r3 As==01
> __asm__( "reti" );
> 1bd2: 00 13 reti
>
> 00001bd4 <BasicTimerIRQ>:
> }
>
> It would appear that this function is acting as if I had the "naked"
> property set (which I don't). This is easily solved by manually adding
> the push and pop statements that account for the registers used. Here's
> my solution:
> __asm__( "push r15" );
> __asm__( "push r14" );
> __asm__( "push r13" );
> __asm__( "push r12" );
> /******* Body of ISR *******/
> __asm__( "pop r12" );
> __asm__( "pop r13" );
> __asm__( "pop r14" );
> __asm__( "pop r15" );
>
> This works, but obviously, I shouldn't have to do this.
> Cheers
> -Mark Stokes
>
>
>
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