[avr-gcc-list] Horrible code

James L. Evans Tue, 16 May 2006 15:47:33 -0700

Could someone with a 4.1 version of the AVR-GCC compiler please compile
the following code (-Os) and see if it generates better code than the
horrible code (25 instructions) generated for Case 2 by version 3.4.3?


Thanks,

Jim Evans


#include <inttypes.h>
#include <avr/io.h>

void test7(void) {
    while (PINA & 0x40) PORTA = 0;                  // Case 1

    while ((PINA & 0x40) == 0) PORTA = 0;           // Case 2

    while (!(PINA & 0x40)) PORTA = 0;               // Case 3

    uint8_t b;
    while ((b = (PINA & 0x40)) == 0) PORTA = 0;     // Case 4
}


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[avr-gcc-list] Horrible code

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