From 6b82be0624b827e825ad2f9912ab6a9bbcbb48f9 Mon Sep 17 00:00:00 2001
From: TomW <TomW@localhost>
Date: Tue, 15 Sep 2015 21:53:45 +0100
Subject: [PATCH] Tweaks to PIT latch operation - Juko XT now boots again.

---
 src/ibm.h | 1 +
 src/pit.c | 8 ++++++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/ibm.h b/src/ibm.h
index d19e7f3..8830cbb 100644
--- a/src/ibm.h
+++ b/src/ibm.h
@@ -213,6 +213,7 @@ typedef struct PIT
         int count[3];
         int using_timer[3];
         int initial[3];
+        int latched[3];
 } PIT;
 
 PIT pit;
diff --git a/src/pit.c b/src/pit.c
index ffb8509..a8277db 100644
--- a/src/pit.c
+++ b/src/pit.c
@@ -336,6 +336,7 @@ void pit_write(uint16_t addr, uint8_t val, void *priv)
                         pit.ctrl |= 0x30;
                         pit.rereadlatch[t] = 0;
                         pit.rm[t] = 3;
+                        pit.latched[t] = 1;
                 }
                 else
                 {
@@ -348,7 +349,7 @@ void pit_write(uint16_t addr, uint8_t val, void *priv)
                                 pit.rm[val>>6]=3;
                                 pit.rl[t] = pit_read_timer(t);
                         }
-//                        pit.rereadlatch[val>>6]=1;
+                        pit.rereadlatch[val>>6]=1;
                         if ((val>>6)==2) ppispeakon=speakon=(pit.m[2]==0)?0:1;
                         pit.initial[t] = 1;
                         if (!pit.m[val >> 6])
@@ -421,7 +422,7 @@ uint8_t pit_read(uint16_t addr, void *priv)
         {
                 case 0: case 1: case 2: /*Timers*/
                 t = addr & 3;
-                if (pit.rereadlatch[addr & 3])
+                if (pit.rereadlatch[addr & 3] && !pit.latched[addr & 3])
                 {
                         pit.rereadlatch[addr & 3] = 0;
                         pit.rl[t] = pit_read_timer(t);
@@ -431,14 +432,17 @@ uint8_t pit_read(uint16_t addr, void *priv)
                         case 0:
                         temp = pit.rl[addr & 3] >> 8;
                         pit.rm[addr & 3] = 3;
+                        pit.latched[addr & 3] = 0;
                         pit.rereadlatch[addr & 3] = 1;
                         break;
                         case 1:
                         temp = (pit.rl[addr & 3]) & 0xFF;
+                        pit.latched[addr & 3] = 0;
                         pit.rereadlatch[addr & 3] = 1;
                         break;
                         case 2:
                         temp = (pit.rl[addr & 3]) >> 8;
+                        pit.latched[addr & 3] = 0;
                         pit.rereadlatch[addr & 3] = 1;
                         break;
                         case 3: