> Looking at assembly listings of the Linux kernel I see thousands of
> places where function returns are checked to be non-zero to indicate
> errors. For example something like this:
>
> mov bx, 0
> .L1
> call foo
> test ax,ax
> jnz .Lerror
Another calling convention could be to not only return the "return value"
in %eax (or %edx:%eax for long long returns) but also its comparisson to
zero in the flags, so that you get:
call foo
jg .Lwarning
jnz .Lerror
The test is done in the called function, but it is often do there anyway,
for instance when another internal function failed there is a chain of
return and the same %eax value is tested over and over again, in each
function body, followed by a return.
Etienne.
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