as: MIPS autoextend
9.26.7 Directives for extending MIPS 16 bit instructions
--------------------------------------------------------
By default, MIPS 16 instructions are automatically extended to 32 bits
when necessary. The directive '.set noautoextend' will turn this off.
When '.set noautoextend' is in effect, any 32 bit instruction must be
explicitly extended with the '.e' modifier (e.g., 'li.e $4,1000'). The
directive '.set autoextend' may be used to once again automatically
extend instructions when necessary.
This directive is only meaningful when in MIPS 16 mode. Traditional
MIPS assemblers do not support this directive.