From: Toni Wilen <twilen@winuae.net>
Date: Mon, 2 Jan 2023 18:54:07 +0000 (+0200)
Subject: Update DSKBYTR only when data is available, remove unneeded dsksync hacks.
X-Git-Tag: 41010~29
X-Git-Url: https://git.unchartedbackwaters.co.uk/w/?a=commitdiff_plain;h=e076baebb5325840f29f2a8c1e4722389b4b5c13;p=francis%2Fwinuae.git

Update DSKBYTR only when data is available, remove unneeded dsksync hacks.
---

diff --git a/disk.cpp b/disk.cpp
index 87cb9861..baaa83e8 100644
--- a/disk.cpp
+++ b/disk.cpp
@@ -128,8 +128,6 @@ static int fifo_inuse[3];
 static int dma_enable, bitoffset, syncoffset;
 static uae_u16 word, dsksync;
 static bool dsksync_on;
-static evt_t dsksync_cycles;
-#define WORDSYNC_TIME 11
 /* Always carried through to the next line.  */
 int disk_hpos;
 static int disk_jitter;
@@ -4104,7 +4102,6 @@ static int doreaddma (void)
 
 static void wordsync_detected(bool startup)
 {
-	dsksync_cycles = get_cycles() + WORDSYNC_TIME * CYCLE_UNIT;
 	if (dskdmaen != DSKDMA_OFF) {
 		if (disk_debug_logging && dma_enable == 0) {
 			int pos = -1;
@@ -4131,6 +4128,11 @@ static void wordsync_detected(bool startup)
 	}
 }
 
+static bool canloaddskbytr(void)
+{
+	return (bitoffset & 7) == 7 && (word & 0xff) != 0x00 && (word & 0xff) != 0xff;
+}
+
 static void disk_doupdate_read_reallynothing(int floppybits, bool state)
 {
 	while (floppybits >= get_floppy_speed()) {
@@ -4150,7 +4152,7 @@ static void disk_doupdate_read_reallynothing(int floppybits, bool state)
 				skipbit = true;
 			}
 		}
-		if (!skipbit && (bitoffset & 7) == 7 && !waszero) {
+		if (!skipbit && canloaddskbytr()) {
 			dskbytr_val = word & 0xff;
 			dskbytr_val |= 0x8000;
 		}
@@ -4185,7 +4187,7 @@ static void disk_doupdate_read_nothing(int floppybits)
 				skipbit = true;
 			}
 		}
-		if (!skipbit && (bitoffset & 7) == 7) {
+		if (!skipbit && canloaddskbytr()) {
 			dskbytr_val = word & 0xff;
 			dskbytr_val |= 0x8000;
 		}
@@ -4289,7 +4291,7 @@ static void disk_doupdate_read (drive * drv, int floppybits)
 			}
 		}
 
-		if (!skipbit && (bitoffset & 7) == 7) {
+		if (!skipbit && canloaddskbytr()) {
 			dskbytr_val = word & 0xff;
 			dskbytr_val |= 0x8000;
 		}
@@ -4326,7 +4328,7 @@ uae_u16 DSKBYTR(int hpos)
 	DISK_update(hpos);
 	v = dskbytr_val;
 	dskbytr_val &= ~0x8000;
-	if (word == dsksync && cycles_in_range(dsksync_cycles)) {
+	if (word == dsksync) {
 		v |= 0x1000;
 		if (disk_debug_logging > 1) {
 			dumpdisk(_T("DSKBYTR SYNC"));