From 219522a911512c0f1cbe9244e609d4fb464f08b2 Mon Sep 17 00:00:00 2001
From: George Wright <gw@gwright.org.uk>
Date: Sun, 8 Dec 2024 12:50:47 -0800
Subject: [PATCH] fix falling edge detect with asic14 and gpio handled state.
 fix ostimer ticks

---
 WindCore/sa1100.cpp                 |  4 +++-
 WindCore/sa1100.h                   |  1 +
 WindCore/sa1100/asic14.cpp          |  1 +
 WindCore/sa1100/asic14.h            | 11 ++++++++++-
 WindCore/sa1100/gpio_controller.cpp |  4 ----
 WindCore/sa1100/gpio_controller.h   |  2 +-
 6 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/WindCore/sa1100.cpp b/WindCore/sa1100.cpp
index e2e8cd2..36f02ec 100644
--- a/WindCore/sa1100.cpp
+++ b/WindCore/sa1100.cpp
@@ -957,6 +957,7 @@ void Emulator::configure() {
 
 	nextTickAt = TICK_INTERVAL;
 	nextRTCTick = 0;
+	nextTimerTick = 0;
 	memoryConfig.reset();
 	setProcessorID(0x4401A111);
 	powerManager->reset();
@@ -1011,8 +1012,9 @@ bool Emulator::executeUntil(int64_t cycles) {
 			pendingInterrupts |= (1<<TINT);
 			asic14->tick();
 		}
-		if (passedCycles % TICKS_3_6864_MHZ == 0) {
+		if (passedCycles >= nextTimerTick) {
 			osTimer->tick();
+			nextTimerTick += TICKS_3_6864_MHZ;
 		}
 		if (passedCycles >= nextRTCTick) {
 			printf("RTC tick\n");
diff --git a/WindCore/sa1100.h b/WindCore/sa1100.h
index 6212d85..9969df8 100644
--- a/WindCore/sa1100.h
+++ b/WindCore/sa1100.h
@@ -52,6 +52,7 @@ private:
 	uint16_t lastSSIRequest = 0;
 	int ssiReadCounter = 0;
 	uint32_t nextRTCTick = 0;
+	uint32_t nextTimerTick = 0;
 
 	uint32_t kScan = 0;
 	uint8_t keyboardColumns[8] = {0,0,0,0,0,0,0};
diff --git a/WindCore/sa1100/asic14.cpp b/WindCore/sa1100/asic14.cpp
index cf23854..5976020 100644
--- a/WindCore/sa1100/asic14.cpp
+++ b/WindCore/sa1100/asic14.cpp
@@ -57,6 +57,7 @@ namespace SA1100 {
     m_SPI_DATA = 0;
     m_SPI_FN = 0;
     m_STATUS6 = (1 << 1) | (1 << 10) | (1 << 11);
+    pinState = false;
   }
   
   void ASIC14::run() {}
diff --git a/WindCore/sa1100/asic14.h b/WindCore/sa1100/asic14.h
index a43f6ef..76ed243 100644
--- a/WindCore/sa1100/asic14.h
+++ b/WindCore/sa1100/asic14.h
@@ -41,6 +41,7 @@ class ASIC14 {
 
   private:
     uint8_t prom[0x80] = {};
+    bool pinState;
     int mCurrPlace = 0;
     GPIOController* mGPIOController;
     enum
@@ -113,9 +114,17 @@ class ASIC14 {
       //m_IRQ_STATUS = IRQ_CFCARD_CHANGE | IRQ_PCMCIA_CHANGE;
       m_IRQ_STATUS = m_IRQ_MASK;
       if (m_IRQ_STATUS != 0) {
-        mGPIOController->pull_pin(10, false);
+        if (pinState == false) {
+          // Go high for one cycle, then low next cycle.
+          mGPIOController->pull_pin(10, true);
+          pinState = true;
+        } else {
+          mGPIOController->pull_pin(10, false);
+          pinState = false;
+        }
       } else {
         mGPIOController->pull_pin(10, true);
+        pinState = true;
       }
     }
 };
diff --git a/WindCore/sa1100/gpio_controller.cpp b/WindCore/sa1100/gpio_controller.cpp
index ec26152..f760415 100644
--- a/WindCore/sa1100/gpio_controller.cpp
+++ b/WindCore/sa1100/gpio_controller.cpp
@@ -126,10 +126,6 @@ namespace SA1100 {
       // GEDR status bits are cleared by writing a one to them.
       // Writing a zero to a GEDR status bit has no effect.
       m_GEDR &= ~(value & 0xFFFFFFF);
-      // Probably not the best way to handle this, as reading GPLR will result in incorrect
-      // data
-      m_GPLR &= ~(value & 0xFFFFFFF);
-      m_GPLR_backup &= ~(value & 0xFFFFFFF);
       //printf("GEDR write %08x [%08x]\n", value, m_GEDR);
       break;
       
diff --git a/WindCore/sa1100/gpio_controller.h b/WindCore/sa1100/gpio_controller.h
index 0c3b75b..e614ed0 100644
--- a/WindCore/sa1100/gpio_controller.h
+++ b/WindCore/sa1100/gpio_controller.h
@@ -101,7 +101,7 @@ class GPIOController {
     
     inline void run() {
       uint32_t const temp = m_GPLR ^ m_GPLR_backup;
-      
+
       if (temp != 0) {
         m_GEDR |= (m_GRER & (m_GPLR & temp));
         m_GEDR |= (m_GFER & (m_GPLR_backup & temp));
-- 
2.45.2