On 2015-03-04 02:58, Qiu, Michael wrote: > On 3/3/2015 9:38 PM, Wodkowski, PawelX wrote: >>> -----Original Message----- >>> From: Qiu, Michael >>> Sent: Tuesday, March 03, 2015 11:00 AM >>> To: Wodkowski, PawelX; dev at dpdk.org >>> Subject: Re: [dpdk-dev] [PATCH v2] librte_eal/common: Fix cast from pointer >>> to >>> integer of different size >>> >>> On 3/3/2015 4:25 PM, Wodkowski, PawelX wrote: >>>> On 2015-03-03 03:20, Michael Qiu wrote: >>>>> /i686-native-linuxapp-gcc/include/rte_memcpy.h:592:23: error: >>>>> cast from pointer to integer of different size >>>>> [-Werror=pointer-to-int-cast] >>>>> >>>>> dstofss = 16 - (int)((long long)(void *)dst & 0x0F) + 16; >>>>> >>>>> Type 'long long' is 64-bit in i686 platform while 'void *' >>>>> is 32-bit. >>>>> >>>>> Signed-off-by: Michael Qiu <michael.qiu at intel.com> >>>>> --- >>>>> v2 --> v1: >>>>> Remove unnecessary casting (void *) >>>>> >>>>> lib/librte_eal/common/include/arch/x86/rte_memcpy.h | 4 ++-- >>>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>>> >>>>> diff --git a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h >>> b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h >>>>> index 7b2d382..85a5f4d 100644 >>>>> --- a/lib/librte_eal/common/include/arch/x86/rte_memcpy.h >>>>> +++ b/lib/librte_eal/common/include/arch/x86/rte_memcpy.h >>>>> @@ -589,12 +589,12 @@ COPY_BLOCK_64_BACK15: >>>>> * unaligned copy functions require up to 15 bytes >>>>> * backwards access. >>>>> */ >>>>> - dstofss = 16 - (int)((long long)(void *)dst & 0x0F) + 16; >>>>> + dstofss = 16 - (int)((long)dst & 0x0F) + 16; >>>>> n -= dstofss; >>>>> rte_mov32((uint8_t *)dst, (const uint8_t *)src); >>>>> src = (const uint8_t *)src + dstofss; >>>>> dst = (uint8_t *)dst + dstofss; >>>>> - srcofs = (int)((long long)(const void *)src & 0x0F); >>>>> + srcofs = (int)((long)src & 0x0F); >>>>> >>>>> /** >>>>> * For aligned copy >>>>> >>>> I think you should use here size_t, (u)ptrdiff_t or (u)intptr_t as this >>> Yes, but 'long' is enough, does it limit anything, or has any issue with >>> multiple platforms? >>> >> Those types ((u)ptrdiff_t, (u)intptr_t) exists specially for >> pointer-to-int and int-to-pointer casts. Using integer primitives might >> produce further warnings/error in the future and need further patches >> fixing the same place. > > OK, I will send out the v3 patch. > >> Also why make offset variables signed and different type? This introduce >> a lot of unnecessary explicit and implicit casts or type promotions. > > But Is it suitable to make offset (u)ptrdiff_t or (u)intptr_t? >
I think, as final result is offset, its type should be size_t (the same type as type of offsetof() macro). This way you can use uptrdiff_t/uintptr_t and does not need of any signed-unsigned casting. > Thanks, > Michael > >>>> will be more portable. >>>> Also type of dstofss and srcofs should be changed accordingly. >>> No, I think, it should be offset. >>> >>> Thanks, >>> Michael >> > > -- Pawel
