3cea09271b
PACK fails on the test from the Principles of Operation: F1F2F3F4 becomes 0000234C instead of 0001234C due to an off-by-one error. Furthermore, it overwrites one extra byte to the left of F1. If len_dest is 0, then we only want to flip the 1st byte and never loop over the rest. Therefore, the loop condition should be > and not >=. If len_src is 1, then we should flip the 1st byte and pack the 2nd. Since len_src is already decremented before the loop, the first condition should be >=, and not >. Likewise for len_src == 2 and the second condition. Signed-off-by: Pavel Zbitskiy <pavel.zbitskiy@gmail.com> Message-Id: <20180821025104.19604-7-pavel.zbitskiy@gmail.com> Reviewed-by: David Hildenbrand <david@redhat.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
22 lines
469 B
C
22 lines
469 B
C
#include <unistd.h>
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int main(void)
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{
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char data[] = {0xaa, 0xaa, 0xf1, 0xf2, 0xf3, 0xc4, 0xaa, 0xaa};
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char exp[] = {0xaa, 0xaa, 0x00, 0x01, 0x23, 0x4c, 0xaa, 0xaa};
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int i;
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asm volatile(
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" pack 2(4,%[data]),2(4,%[data])\n"
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:
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: [data] "r" (&data[0])
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: "memory");
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for (i = 0; i < 8; i++) {
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if (data[i] != exp[i]) {
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write(1, "bad data\n", 9);
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return 1;
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}
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}
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return 0;
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}
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