From 93615f6647eeedb05068627daa87bd62af801406 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 15 Jun 2022 10:50:03 -0400
Subject: [PATCH 1/4] Apply new status before entering STOP loop.
---
.../Implementation/68000Mk2Implementation.hpp | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index 1acfef412..8eb34a825 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -27,6 +27,7 @@ enum ExecutionState: int {
Reset = std::numeric_limits<int>::min(),
Decode,
WaitForDTACK,
+ WaitForInterrupt,
StoreOperand,
StoreOperand_bw,
@@ -377,14 +378,20 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
}
MoveToStateSpecific(WaitForDTACK);
- // Spin in place until an interrupt arrives.
BeginState(STOP):
- IdleBus(1);
+ // Apply the suffix status.
+ status_.set_status(operand_[0].w);
+ did_update_status();
+ [[fallthrough]];
+
+ BeginState(WaitForInterrupt):
+ // Spin in place until an interrupt arrives.
captured_interrupt_level_ = bus_interrupt_level_;
if(status_.would_accept_interrupt(captured_interrupt_level_)) {
MoveToStateSpecific(DoInterrupt);
}
- MoveToStateSpecific(STOP);
+ IdleBus(1);
+ MoveToStateSpecific(WaitForInterrupt);
// Perform the RESET exception, which seeds the stack pointer and program
// counter, populates the prefetch queue, and then moves to instruction dispatch.
From 5420fd5aa3421705052d134b10c505b0d6604241 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 15 Jun 2022 10:54:14 -0400
Subject: [PATCH 2/4] Fix: new status word is still in prefetch.
---
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index 8eb34a825..b1222483f 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -380,7 +380,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
BeginState(STOP):
// Apply the suffix status.
- status_.set_status(operand_[0].w);
+ status_.set_status(prefetch_.w);
did_update_status();
[[fallthrough]];
From bd056973ba68438383dc48c98a8bcd1d1fbc3142 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 15 Jun 2022 10:56:45 -0400
Subject: [PATCH 3/4] Don't allow STOP state to block execution.
---
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp | 1 +
1 file changed, 1 insertion(+)
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index b1222483f..7b043d56c 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -391,6 +391,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
MoveToStateSpecific(DoInterrupt);
}
IdleBus(1);
+ CheckOverrun();
MoveToStateSpecific(WaitForInterrupt);
// Perform the RESET exception, which seeds the stack pointer and program
From 24823233ff6eecf81c3656bbf86c054969b4f280 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Wed, 15 Jun 2022 11:00:27 -0400
Subject: [PATCH 4/4] Add spurious interrupt support.
---
.../68000Mk2/Implementation/68000Mk2Implementation.hpp | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
index 7b043d56c..f26df65c8 100644
--- a/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
+++ b/Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
@@ -595,8 +595,12 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
if(vpa_) {
temporary_value_.b = uint8_t(InstructionSet::M68k::Exception::InterruptAutovectorBase - 1 + captured_interrupt_level_);
}
+ if(berr_) {
+ temporary_value_.b = uint8_t(InstructionSet::M68k::Exception::SpuriousInterrupt);
+ }
- // TODO: if bus error is set, treat interrupt as spurious.
+ // TODO: check documentation for other potential interrupt outcomes;
+ // and presumably spin here if DTACK isn't implicit.
IdleBus(3); // n- n