[avr-gcc-list] interrupt in as

[Torsten Hahn]

Hi,

can explain me somebody how can i implement an interrupt-handler purely in 
assembler ?

I would need an interrupt routine with no overhead from the c-compiler. If I 
use

SIGNAL(INTERRUPT0)
{
asm("nop");
}

I get code output like this:

000000b4 <_interrupt1_>:
  b4:   1f 92           push    r1
  b6:   0f 92           push    r0
  b8:   0f b6           in      r0, 0x3f        ; 63
  ba:   0f 92           push    r0
  bc:   11 24           eor     r1, r1
  be:   00 00           nop
  c0:   0f 90           pop     r0
  c2:   0f be           out     0x3f, r0        ; 63
  c4:   0f 90           pop     r0
  c6:   1f 90           pop     r1
  c8:   18 95           reti

The Problem is now, that i have an extremly time critical applikation and i 
have for some reasons only 16 (!) takt-cycles to handle this interrupt 
optimal. The code constructet wasts about 12 of them.

Thanks,
TH.
-- 
Torsten Hahn / Chemnitzer Str. 4 / 09599 Freiberg / Germany
mail: address@hidden
phone: (+49) 177 2181338
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