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[avr-gcc-list] saving and restoring context

From: juan antonio jimenez martinez
Subject: [avr-gcc-list] saving and restoring context
Date: Sat, 19 Nov 2005 16:50:02 +0000

Hi, Im writing a couple of functions in assembler for the ATMEGA8, and I store the value of the registers that Im using in the stack, but when I get in to the assembler output generated by winavr, apears at the begining of the fuction another context saving of extra registers, is there a way to skip this and do it by my self??

!!!how can I skip this lines¡¡¡¡

unsigned char serial_in(){
 5c:    cf 93           push    r28
 5e:    df 93           push    r29
 60:    cd b7           in      r28, 0x3d       ; 61
 62:    de b7           in      r29, 0x3e       ; 62
 64:    21 97           sbiw    r28, 0x01       ; 1
 66:    0f b6           in      r0, 0x3f        ; 63
 68:    f8 94           cli
 6a:    de bf           out     0x3e, r29       ; 62
 6c:    0f be           out     0x3f, r0        ; 63
 6e:    cd bf           out     0x3d, r28       ; 61

unsigned char Rxbyte;

!!! Is there any way that my fuction starts from here ¡¡¡

asm volatile(
 70:    1f 93           push    r17
 72:    2f 93           push    r18
 74:    1f b7           in      r17, 0x3f       ; 63
 76:    29 e0           ldi     r18, 0x09       ; 9




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