Messages in this thread | | | From | Vladimir Murzin <> | Subject | Re: [PATCH] arm: memset: zero out upper bytes in r1 | Date | Thu, 8 May 2014 08:04:44 +0000 (UTC) |
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Andrey Ryabinin <a.ryabinin <at> samsung.com> writes:
> > memset doesn't work right for following example: > > signed char c = 0xF0; > memset(addr, c, size); > > Variable c is signed, so after typcasting to int the value will be 0xFFFFFFF0. > This value will be passed through r1 regitster to memset function. > memset doesn't zero out upper bytes in r1, so memory will be filled > with 0xFFFFFFF0 instead of expected 0xF0F0F0F0.
It behaves the same as a generic implementation in lib/string.c, moreover gcc built-in behaves the same. So it looks like expected behavior and POSIX Programmer's Manual (man 3posix memset) explicitly says that "c" is converted to unsigned char.
Cheers Vladimir
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