mos6522_read() and mos6522_write() may call various functions to determine
timer irq state, timer counter value and QEMUTimer deadline. All called
functions must use the same value for the present time.
Signed-off-by: Finn Thain <fth...@linux-m68k.org>
---
hw/misc/mos6522.c | 51 +++++++++++++++++++++++++----------------------
1 file changed, 27 insertions(+), 24 deletions(-)
diff --git a/hw/misc/mos6522.c b/hw/misc/mos6522.c
index 0dd3ccf945..23a440b64f 100644
--- a/hw/misc/mos6522.c
+++ b/hw/misc/mos6522.c
@@ -39,9 +39,9 @@
/* XXX: implement all timer modes */
static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
- int64_t current_time);
+ int64_t now);
static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
- int64_t current_time);
+ int64_t now);
static void mos6522_update_irq(MOS6522State *s)
{
@@ -52,12 +52,12 @@ static void mos6522_update_irq(MOS6522State *s)
}
}
-static unsigned int get_counter(MOS6522State *s, MOS6522Timer *ti)
+static unsigned int get_counter(MOS6522State *s, MOS6522Timer *ti, int64_t now)
{
int64_t d;
unsigned int counter;
- d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
+ d = muldiv64(now - ti->load_time,
ti->frequency, NANOSECONDS_PER_SECOND);
if (ti->index == 0) {
@@ -89,7 +89,7 @@ static void set_counter(MOS6522State *s, MOS6522Timer *ti,
unsigned int val)
}
static int64_t get_next_irq_time(MOS6522State *s, MOS6522Timer *ti,
- int64_t current_time)
+ int64_t now)
{
int64_t d, next_time;
unsigned int counter;
@@ -99,7 +99,7 @@ static int64_t get_next_irq_time(MOS6522State *s,
MOS6522Timer *ti,
}
/* current counter value */
- d = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - ti->load_time,
+ d = muldiv64(now - ti->load_time,
ti->frequency, NANOSECONDS_PER_SECOND);
/* the timer goes down from latch to -1 (period of latch + 2) */
@@ -123,20 +123,19 @@ static int64_t get_next_irq_time(MOS6522State *s,
MOS6522Timer *ti,
trace_mos6522_get_next_irq_time(ti->latch, d, next_time - d);
next_time = muldiv64(next_time, NANOSECONDS_PER_SECOND, ti->frequency) +
ti->load_time;
-
- if (next_time <= current_time) {
- next_time = current_time + 1;
- }
return next_time;
}
static void mos6522_timer1_update(MOS6522State *s, MOS6522Timer *ti,
- int64_t current_time)
+ int64_t now)
{
if (!ti->timer) {
return;
}
- ti->next_irq_time = get_next_irq_time(s, ti, current_time);
+ ti->next_irq_time = get_next_irq_time(s, ti, now);
+ if (ti->next_irq_time <= now) {
+ ti->next_irq_time = now + 1;
+ }
if ((s->ier & T1_INT) == 0 ||
((s->acr & T1MODE) == T1MODE_ONESHOT && ti->oneshot_fired)) {
timer_del(ti->timer);
@@ -146,12 +145,15 @@ static void mos6522_timer1_update(MOS6522State *s,
MOS6522Timer *ti,
}
static void mos6522_timer2_update(MOS6522State *s, MOS6522Timer *ti,
- int64_t current_time)
+ int64_t now)
{
if (!ti->timer) {
return;
}
- ti->next_irq_time = get_next_irq_time(s, ti, current_time);
+ ti->next_irq_time = get_next_irq_time(s, ti, now);
+ if (ti->next_irq_time <= now) {
+ ti->next_irq_time = now + 1;
+ }
if ((s->ier & T2_INT) == 0 || (s->acr & T2MODE) || ti->oneshot_fired) {
timer_del(ti->timer);
} else {
@@ -163,9 +165,10 @@ static void mos6522_timer1_expired(void *opaque)
{
MOS6522State *s = opaque;
MOS6522Timer *ti = &s->timers[0];
+ int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ti->oneshot_fired = true;
- mos6522_timer1_update(s, ti, ti->next_irq_time);
+ mos6522_timer1_update(s, ti, now);
s->ifr |= T1_INT;
mos6522_update_irq(s);
}
@@ -174,9 +177,10 @@ static void mos6522_timer2_expired(void *opaque)
{
MOS6522State *s = opaque;
MOS6522Timer *ti = &s->timers[1];
+ int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
ti->oneshot_fired = true;
- mos6522_timer2_update(s, ti, ti->next_irq_time);
+ mos6522_timer2_update(s, ti, now);
s->ifr |= T2_INT;
mos6522_update_irq(s);
}
@@ -233,12 +237,12 @@ uint64_t mos6522_read(void *opaque, hwaddr addr, unsigned
size)
val = s->dira;
break;
case VIA_REG_T1CL:
- val = get_counter(s, &s->timers[0]) & 0xff;
+ val = get_counter(s, &s->timers[0], now) & 0xff;
s->ifr &= ~T1_INT;
mos6522_update_irq(s);
break;
case VIA_REG_T1CH:
- val = get_counter(s, &s->timers[0]) >> 8;
+ val = get_counter(s, &s->timers[0], now) >> 8;
break;
case VIA_REG_T1LL:
val = s->timers[0].latch & 0xff;
@@ -247,12 +251,12 @@ uint64_t mos6522_read(void *opaque, hwaddr addr, unsigned
size)
val = (s->timers[0].latch >> 8) & 0xff;
break;
case VIA_REG_T2CL:
- val = get_counter(s, &s->timers[1]) & 0xff;
+ val = get_counter(s, &s->timers[1], now) & 0xff;
s->ifr &= ~T2_INT;
mos6522_update_irq(s);
break;
case VIA_REG_T2CH:
- val = get_counter(s, &s->timers[1]) >> 8;
+ val = get_counter(s, &s->timers[1], now) >> 8;
break;
case VIA_REG_SR:
val = s->sr;
@@ -360,10 +364,9 @@ void mos6522_write(void *opaque, hwaddr addr, uint64_t
val, unsigned size)
}
mos6522_update_irq(s);
/* if IER is modified starts needed timers */
- mos6522_timer1_update(s, &s->timers[0],
- qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
- mos6522_timer2_update(s, &s->timers[1],
- qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
+ now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ mos6522_timer1_update(s, &s->timers[0], now);
+ mos6522_timer2_update(s, &s->timers[1], now);
break;
default:
g_assert_not_reached();
--
2.26.3
