[vlc-devel] [PATCH] modules: use 16-bit ints for option counts

Rémi Denis-Courmont remi at remlab.net
Sun Sep 27 21:02:58 CEST 2020


Le sunnuntaina 27. syyskuuta 2020, 21.38.08 EEST Lyndon Brown a écrit :
> Whenever we rarely use the counts for indexing or iteration or allocation,
> they'll get auto-zero-extended to int/size_t size as necessary.

That's not entirely correct.

Historically, some ISA lacked instructions for loading and storing non-native 
sizes, notably 16-bit values on 32-bit systems. While that is generally not a 
problem anymore, contemporary ISAs still have limitations on 16-bit accesses.

For instance the ARM A64 ISA can load 2 contiguous 64-bit, signed 32-bit, 
unsigned 32-bit values in a single instruction. It can't do that with 16-bit 
values.

-- 
Rémi Denis-Courmont
http://www.remlab.net/





More information about the vlc-devel mailing list