62 lines
1.4 KiB
C
62 lines
1.4 KiB
C
static int simple_jump(void)
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{
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asm goto ("jmp %l[label]" : : : : label);
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return 0;
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label:
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return 1;
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}
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static int three_way_jump(int val, int *addr)
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{
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*addr = 42;
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asm goto ("cmp $0, %1\n\t"
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"jg %l[larger]\n\t"
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"jl %l[smaller]\n\t"
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"incl %0\n\t"
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: "=m" (*addr)
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: "r" (val)
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:
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: smaller, larger);
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return 1;
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smaller:
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return 2;
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larger:
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return 3;
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}
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static int another_jump(void)
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{
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asm goto ("jmp %l[label]" : : : : label);
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return 70;
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/* Use the same label name as in simple_jump to check that
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that doesn't confuse our C/ASM symbol tables */
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label:
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return 71;
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}
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extern int printf (const char *, ...);
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int main(void)
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{
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int i;
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if (simple_jump () == 1)
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printf ("simple_jump: okay\n");
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else
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printf ("simple_jump: wrong\n");
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if (another_jump () == 71)
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printf ("another_jump: okay\n");
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else
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printf ("another_jump: wrong\n");
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if (three_way_jump(0, &i) == 1 && i == 43)
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printf ("three_way_jump(0): okay\n");
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else
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printf ("three_way_jump(0): wrong (i=%d)\n", i);
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if (three_way_jump(1, &i) == 3 && i == 42)
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printf ("three_way_jump(1): okay\n");
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else
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printf ("three_way_jump(1): wrong (i=%d)\n", i);
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if (three_way_jump(-1, &i) == 2 && i == 42)
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printf ("three_way_jump(-1): okay\n");
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else
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printf ("three_way_jump(-1): wrong (i=%d)\n", i);
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return 0;
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}
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