[U-Boot] [PATCH] mkimage: Fix generating multi and script images again

Marek Vasut marex at denx.de
Mon Dec 7 19:05:12 CET 2015


On Monday, December 07, 2015 at 06:47:36 PM, Wolfgang Denk wrote:
> Dear Marek,
> 
> In message <1449507714-9599-1-git-send-email-marex at denx.de> you wrote:
> > Second is the coding which causes gcc 4.9.x and newer scream gruesome
> > death and murder. The expression !x == 0 && !x == 1 is ambiguous and
> > should instead be rewritten into (x != 0) && (x != 1) to be correct.
> 
> But (!x == 0) && (!x == 1) ist not the same as (x != 0) && (x != 1);
> assume x=2:
> 
> 	(!2 == 0) && (!2 == 1) => (0 == 0) && (0 == 1) => 1 && 0 => 0
> 
> 	(2 != 0) && (2 != 1) => 1 && 1 => 1
> 
> ???

This really depends on where you put the parenthesis and GCC complains
about such ambiguous expressions. That's what the paragraph is about.
I never said that ((!x) == 0) && ((!x) == 1) <=> (x != 0) && (x != 1) 
or equally ((!x) == 0) && ((!x) == 1) <=> !(x == 0) && !(x == 1)

Best regards,
Marek Vasut


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