On 2015-07-05 20:05, Serge Vakulenko wrote:
> >> } else {
> >> /* A MIPS configured with compatibility or VInt (Vectored
> >> Interrupts)
> >> diff --git a/target-mips/helper.c b/target-mips/helper.c
> >> index 8e3204a..7e25998 100644
> >> --- a/target-mips/helper.c
> >> +++ b/target-mips/helper.c
> >> @@ -574,23 +574,31 @@ void mips_cpu_do_interrupt(CPUState *cs)
> >> unsigned int vector;
> >> unsigned int pending = (env->CP0_Cause & CP0Ca_IP_mask) >> 8;
> >>
> >> - pending &= env->CP0_Status >> 8;
> >> /* Compute the Vector Spacing. */
> >> spacing = (env->CP0_IntCtl >> CP0IntCtl_VS) & ((1 << 6) - 1);
> >> spacing <<= 5;
> >>
> >> - if (env->CP0_Config3 & (1 << CP0C3_VInt)) {
> >> + if (env->CP0_Config3 & (1 << CP0C3_VEIC)) {
> >> + /* For VEIC mode, the external interrupt controller feeds
> >> the
> >> + * vector through the CP0Cause IP lines. */
> >> + vector = pending;
> >> +
> >> + /* Architecturally, this is chip-specific behavior.
> >> + * TODO: some processors, like PIC32MZ,
> >> + * provide vector in a different way.
> >> + * Some processors, like PIC32, have a separate
> >> + * bit INTCON.MVEC to explicitly enable vectored mode,
> >> + * disabled by default. */
> >> + spacing = 0;
> >> + } else {
> >> /* For VInt mode, the MIPS computes the vector
> >> internally. */
> >> + pending &= env->CP0_Status >> 8;
> >> for (vector = 7; vector > 0; vector--) {
> >> if (pending & (1 << vector)) {
> >> /* Found it. */
> >> break;
> >> }
> >> }
> >> - } else {
> >> - /* For VEIC mode, the external interrupt controller feeds
> >> the
> >> - vector through the CP0Cause IP lines. */
> >> - vector = pending;
> >> }
> >
> > The changes looks correct, but I do wonder why you swap the test on
> > CP0_Config3. It would be less changes to just move the pending masking
> > with CP0_Status inside the VInt mode.
>
> According to MIPS PRA spec (MD00090), VInt bit becomes do-not-care
> when Config3.VEIC is enabled. So it makes little sense to rely on it's
> value here. And it makes it easier to understand this way. EIC and
> VInt modes are quite different: better not to mix them up.
Ok I understand now.
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
[email protected] http://www.aurel32.net
