Re: [PATCH] scsi: aic7xxx: Fix unintended sign extension issue

From: James Bottomley
Date: Thu Oct 25 2018 - 11:33:08 EST


On Thu, 2018-10-25 at 16:13 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> In the expression "ahc_inb(ahc, port+3) << 24", the initial value is
> a u8, but is promoted to a signed int, then sign-extended to
> uint64_t.

Why is this, that's highly non intuitive? The compiler is supposed to
promote to the biggest type, which is uint64_t and then do the
calculation

James