[PATCH v1 9/9] hw/mos6522: Implement oneshot mode

[Finn Thain]

Timer 1 has two modes: continuous interrupt and oneshot.

Signed-off-by: Finn Thain <fthain@linux-m68k.org>
---
Changed since RFC:
 - Moved to end of series. This patch is quite a bit shorter here.
---
 hw/misc/mos6522.c         | 6 ++++--
 include/hw/misc/mos6522.h | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/hw/misc/mos6522.c b/hw/misc/mos6522.c
index 8957c5e65c..bbed0b84c0 100644
--- a/hw/misc/mos6522.c
+++ b/hw/misc/mos6522.c
@@ -148,7 +148,8 @@ static void mos6522_timer1_update(MOS6522State *s, 
MOS6522Timer *ti,
     }
     get_counter(s, ti, now);
     ti->next_irq_time = get_next_irq_time(s, ti, now);
-    if ((s->ier & T1_INT) == 0 || (s->acr & T1MODE) != T1MODE_CONT) {
+    if ((s->ier & T1_INT) == 0 ||
+        ((s->acr & T1MODE) == T1MODE_ONESHOT && ti->state >= irq)) {
         timer_del(ti->timer);
     } else {
         timer_mod(ti->timer, ti->next_irq_time);
@@ -163,7 +164,7 @@ static void mos6522_timer2_update(MOS6522State *s, 
MOS6522Timer *ti,
     }
     get_counter(s, ti, now);
     ti->next_irq_time = get_next_irq_time(s, ti, now);
-    if ((s->ier & T2_INT) == 0) {
+    if ((s->ier & T2_INT) == 0 || (s->acr & T2MODE) || ti->state >= irq) {
         timer_del(ti->timer);
     } else {
         timer_mod(ti->timer, ti->next_irq_time);
@@ -345,6 +346,7 @@ void mos6522_write(void *opaque, hwaddr addr, uint64_t val, 
unsigned size)
     case VIA_REG_ACR:
         s->acr = val;
         mos6522_timer1_update(s, &s->timers[0], now);
+        mos6522_timer2_update(s, &s->timers[1], now);
         break;
     case VIA_REG_PCR:
         s->pcr = val;
diff --git a/include/hw/misc/mos6522.h b/include/hw/misc/mos6522.h
index a2df5fa942..4dbba6b273 100644
--- a/include/hw/misc/mos6522.h
+++ b/include/hw/misc/mos6522.h
@@ -50,8 +50,10 @@
 #define T1_INT             0x40    /* Timer 1 interrupt */
 
 /* Bits in ACR */
+#define T2MODE             0x20    /* Timer 2 mode */
 #define T1MODE             0xc0    /* Timer 1 mode */
 #define T1MODE_CONT        0x40    /*  continuous interrupts */
+#define T1MODE_ONESHOT     0x00    /*  timed interrupt */
 
 /* VIA registers */
 #define VIA_REG_B       0x00
-- 
2.26.3