From 42145a5b8a0f7fb5295abede1ce7a63274ef2e03 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 1 Nov 2021 14:18:58 -0700
Subject: [PATCH] Delay bitplane installation until end of slot.
---
Machines/Amiga/Chipset.cpp | 39 +++++++++++++++++++++++---------------
Machines/Amiga/Chipset.hpp | 3 ++-
2 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/Machines/Amiga/Chipset.cpp b/Machines/Amiga/Chipset.cpp
index 7bd634f2d..4b8e1dde9 100644
--- a/Machines/Amiga/Chipset.cpp
+++ b/Machines/Amiga/Chipset.cpp
@@ -272,16 +272,28 @@ template <int cycle> void Chipset::output() {
if(cycle == line_length_ - 1) {
flush_output();
}
-
- // Update all active pixel shifters.
- bitplane_pixels_.shift(is_high_res_);
- sprite_shifters_[0].shift();
- sprite_shifters_[1].shift();
- sprite_shifters_[2].shift();
- sprite_shifters_[3].shift();
}
}
+ // Update all active pixel shifters.
+ bitplane_pixels_.shift(is_high_res_);
+ sprite_shifters_[0].shift();
+ sprite_shifters_[1].shift();
+ sprite_shifters_[2].shift();
+ sprite_shifters_[3].shift();
+
+ // Reload if anything is pending.
+ if(has_next_bitplanes_) {
+ has_next_bitplanes_ = false;
+ bitplane_pixels_.set(
+ previous_bitplanes_,
+ next_bitplanes_,
+ odd_delay_,
+ even_delay_
+ );
+ previous_bitplanes_ = next_bitplanes_;
+ }
+
#undef LINK
}
@@ -510,14 +522,11 @@ template <bool stop_on_cpu> Chipset::Changes Chipset::run(HalfCycles length) {
}
void Chipset::post_bitplanes(const BitplaneData &data) {
- // Expand this
- bitplane_pixels_.set(
- previous_bitplanes_,
- data,
- odd_delay_,
- even_delay_
- );
- previous_bitplanes_ = data;
+ // Posted bitplanes should be received at the end of the
+ // current memory slot. So put them aside for now, and
+ // deal with them momentarily.
+ has_next_bitplanes_ = true;
+ next_bitplanes_ = data;
}
void Chipset::BitplaneShifter::set(const BitplaneData &previous, const BitplaneData &next, int odd_delay, int even_delay) {
diff --git a/Machines/Amiga/Chipset.hpp b/Machines/Amiga/Chipset.hpp
index a9f33a9dc..399157cb6 100644
--- a/Machines/Amiga/Chipset.hpp
+++ b/Machines/Amiga/Chipset.hpp
@@ -245,7 +245,8 @@ class Chipset: private ClockingHint::Observer {
} bitplanes_;
void post_bitplanes(const BitplaneData &data);
- BitplaneData previous_bitplanes_;
+ BitplaneData next_bitplanes_, previous_bitplanes_;
+ bool has_next_bitplanes_ = false;
class BitplaneShifter {
public: