mirror of
https://github.com/cc65/cc65.git
synced 2024-12-30 20:29:25 +00:00
60 lines
1.6 KiB
C
60 lines
1.6 KiB
C
/*
|
|
!!DESCRIPTION!! equality problem
|
|
!!ORIGIN!! Testsuite
|
|
!!LICENCE!! Public Domain
|
|
*/
|
|
|
|
/*
|
|
Different results, depending on whether constant is on left or right side.
|
|
|
|
The optimizer sometimes makes code that executes the right-side expression
|
|
as eight bits; but then, tests it against the left-side zero as 16 bits.
|
|
The high-byte is garbage; therefore, that test might, or might not, work.
|
|
It depends on the platform and the amount of optimization.
|
|
|
|
http://www.cc65.org/mailarchive/2014-10/11680.html
|
|
http://www.cc65.org/mailarchive/2014-10/11682.html
|
|
http://www.cc65.org/mailarchive/2014-10/11683.html
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
|
|
static unsigned char fails = 4;
|
|
static unsigned char bad[3], good[3];
|
|
|
|
int main(void)
|
|
{
|
|
unsigned char joy_state = 0x7e;
|
|
unsigned a, b;
|
|
|
|
/* NOTE: It fails in only the printf() statements, the other stuff
|
|
below works! */
|
|
printf("bad: %u, ", 0 == (joy_state & 1) );
|
|
printf("good: %u\n", (joy_state & 1) == 0 );
|
|
|
|
sprintf(bad, "%u", 0 == (joy_state & 1) );
|
|
sprintf(good, "%u", (joy_state & 1) == 0 );
|
|
|
|
printf("bad: %u, ", bad[0] - '0' );
|
|
printf("good: %u\n", good[0] - '0' );
|
|
|
|
fails -= bad[0] - '0';
|
|
fails -= good[0] - '0';
|
|
|
|
if (0 == (joy_state & 1)) fails--;
|
|
if ((joy_state & 1) == 0) fails--;
|
|
|
|
printf("failures: %u\n", fails );
|
|
|
|
/* The above printf() returns a value with a zero high-byte.
|
|
** Therefore, the next (broken) statement works (by accident).
|
|
*/
|
|
a = 0 == (joy_state & 1);
|
|
b = (joy_state & 1) == 0;
|
|
|
|
printf("a: %u, ", a );
|
|
printf("b: %u\n", b );
|
|
|
|
return fails;
|
|
}
|