Re: [PATCH][V2] rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-02-16 Thread Alexandre Belloni
On 15/02/2018 at 19:36:14 +, Colin King wrote: > From: Colin Ian King > > The shifting of buf[5] by 24 bits to the left will be promoted to > a 32 bit signed int and then sign-extended to an unsigned long. If > the top bit of buf[5] is set then all then all the upper bits sec > end up as also

Re: [PATCH][V2] rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-02-16 Thread Colin Ian King
On 16/02/18 15:24, Alexandre Belloni wrote: > On 15/02/2018 at 21:44:53 +0100, Alexandre Belloni wrote: >> On 15/02/2018 at 19:36:14 +, Colin King wrote: >>> From: Colin Ian King >>> >>> The shifting of buf[5] by 24 bits to the left will be promoted to >>> a 32 bit signed int and then sign-ext

Re: [PATCH][V2] rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-02-16 Thread Alexandre Belloni
On 15/02/2018 at 21:44:53 +0100, Alexandre Belloni wrote: > On 15/02/2018 at 19:36:14 +, Colin King wrote: > > From: Colin Ian King > > > > The shifting of buf[5] by 24 bits to the left will be promoted to > > a 32 bit signed int and then sign-extended to an unsigned long. If > > the top bit

Re: [PATCH][V2] rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-02-15 Thread Alexandre Belloni
On 15/02/2018 at 19:36:14 +, Colin King wrote: > From: Colin Ian King > > The shifting of buf[5] by 24 bits to the left will be promoted to > a 32 bit signed int and then sign-extended to an unsigned long. If > the top bit of buf[5] is set then all then all the upper bits sec > end up as also

[PATCH][V2] rtc: tx4939: avoid unintended sign extension on a 24 bit shift

2018-02-15 Thread Colin King
From: Colin Ian King The shifting of buf[5] by 24 bits to the left will be promoted to a 32 bit signed int and then sign-extended to an unsigned long. If the top bit of buf[5] is set then all then all the upper bits sec end up as also being set because of the sign-extension. Fix this by casting b