[avr-gcc-list] Oh why....

[Tvrtko A. Ursulin]

Please look at this piece of code:

void    lcd_at(uint8_t line, uint8_t col)
{
 4e8:   36 2f           mov     r19, r22
        uint8_t adr  = col;

        uint8_t l1 = line&1;
 4ea:   28 2f           mov     r18, r24
 4ec:   21 70           andi    r18, 0x01       ; 1
        uint8_t l2 = line&2;
 4ee:   82 70           andi    r24, 0x02       ; 2
        l1 <<= 6;
 4f0:   22 95           swap    r18
 4f2:   22 0f           add     r18, r18
 4f4:   22 0f           add     r18, r18
 4f6:   20 7c           andi    r18, 0xC0       ; 192
        l2 <<= 3;
 4f8:   88 0f           add     r24, r24
 4fa:   88 0f           add     r24, r24
 4fc:   88 0f           add     r24, r24
        adr |= l1 | l2;
 4fe:   28 2b           or      r18, r24
 500:   32 2b           or      r19, r18

        lcd_address(adr);
 502:   30 68           ori     r19, 0x80       ; 128
 504:   83 2f           mov     r24, r19
 506:   b8 df           rcall   .-144           ; 0x478
}
 508:   08 95           ret

Compiler doesn't like LSR/LSL so he rather spends 3(4) cycles instead of 1?

I am confused...totally....


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