Implement EXCP_UDEF, EXCP_DEBUG, EXCP_INTERRUPT, EXCP_ATOMIC and
EXCP_YIELD. The first two generate a signal to the emulated
binary. EXCP_ATOMIC handles atomic operations. The remainder are fancy
nops.
Signed-off-by: Stacey Son <sson@FreeBSD.org> Signed-off-by: Mikaƫl Urankar <mikael.urankar@gmail.com> Signed-off-by: Kyle Evans <kevans@FreeBSD.org> Signed-off-by: Warner Losh <imp@bsdimp.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>