On 05/08/21 13:24, Paolo Bonzini wrote:
On 05/08/21 11:51, Stevie Lavern wrote:
Shouldn't it be:
eflags = cpu_cc_compute_all(env, CC_OP) | (env->df & DF_MASK);
as eflags is entirely reevaluated by "cpu_cc_compute_all" ?
No, both are wrong. env->eflags contains flags other than the
arithmetic flags (OF/SF/ZF/AF/PF/CF) and those have to be preserved.
The right code is in helper_read_eflags. You can move it into
cpu_compute_eflags, and make helper_read_eflags use it.
Ah, actually the two are really the same, the TF/VM bits do not apply to
cpu_compute_eflags so it's correct.
What seems wrong is migration of the EFLAGS register. There should be
code in cpu_pre_save and cpu_post_load to special-case it and setup
CC_DST/CC_OP as done in cpu_load_eflags.
Also, cpu_load_eflags should assert that update_mask does not include
any of the arithmetic flags.
Paolo
