qemu/tests/tcg/s390x/pack.c
Pavel Zbitskiy 3cea09271b target/s390x: fix PACK reading 1 byte less and writing 1 byte more
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>
2018-08-28 17:37:01 +02:00

22 lines
469 B
C

#include <unistd.h>
int main(void)
{
char data[] = {0xaa, 0xaa, 0xf1, 0xf2, 0xf3, 0xc4, 0xaa, 0xaa};
char exp[] = {0xaa, 0xaa, 0x00, 0x01, 0x23, 0x4c, 0xaa, 0xaa};
int i;
asm volatile(
" pack 2(4,%[data]),2(4,%[data])\n"
:
: [data] "r" (&data[0])
: "memory");
for (i = 0; i < 8; i++) {
if (data[i] != exp[i]) {
write(1, "bad data\n", 9);
return 1;
}
}
return 0;
}