Fix unstable serial receive (if data was internally buffered, receiver got them far...

diff --git a/od-win32/serial_win32.cpp b/od-win32/serial_win32.cpp
index 07ea6cc12f90b1e0f8fab56ada98132f01da1ac3..e47e4ddc061c1cd8d827e371b9966ad55e57d580 100644 (file)
--- a/od-win32/serial_win32.cpp
+++ b/od-win32/serial_win32.cpp
@@ -62,6 +62,7 @@ static bool serempty_enabled;
 static bool serxdevice_enabled;
 static uae_u8 serstatus;
 static bool ser_accurate;
+static bool safe_receive;
 static uae_u16 *receive_buf;
 static int receive_buf_size, receive_buf_count;
 
@@ -227,6 +228,7 @@ void SERPER (uae_u16 w)
        if (serper == w && serper_set)  /* don't set baudrate if it's already ok */
                return;
 
+       safe_receive = false;
        serper_set = true;
        ninebit = 0;
        serper = w;
@@ -250,15 +252,15 @@ void SERPER (uae_u16 w)
        mbaud = baud;
 
        serial_period_hsyncs = (((serper & 0x7fff) + 1) * (1 + 8 + ninebit + 1 - 1)) / maxhpos;
-       if (serial_period_hsyncs <= 0)
+       if (serial_period_hsyncs <= 0) {
                serial_period_hsyncs = 1;
+       }
 
 #if SERIALLOGGING > 0
        serial_period_hsyncs = 1;
        seriallog = 1;
 #endif
-       if (log_sercon) {
-               serial_period_hsyncs = 1;
+       if (log_sercon > 0) {
                seriallog = log_sercon;
                seriallog_lf = true;
                write_logx(_T("\n"));
@@ -270,12 +272,18 @@ void SERPER (uae_u16 w)
                write_log(_T("SERIAL: period=%d, baud=%d, hsyncs=%d, bits=%d, PC=%x\n"), w, baud, serial_period_hsyncs, ninebit ? 9 : 8, M68K_GETPC);
        }
 
-       if (ninebit)
+       if (ninebit) {
                baud *= 2;
+       }
        if (currprefs.serial_direct) {
-               if (baud != 31400 && baud < 115200)
+               if (baud != 31400 && baud < 115200) {
                        baud = 115200;
+               }
                serial_period_hsyncs = 1;
+               safe_receive = true;
+       }
+       if (sermap_enabled || serxdevice_enabled) {
+               safe_receive = true;
        }
 
        serial_recv_previous = -1;
@@ -319,6 +327,7 @@ static void serial_rx_irq(void)
        } else {
                INTREQ_INT(11, 0);
        }
+       serdatr_last_got = 0;
 }
 
 bool serreceive_external(uae_u16 v)
@@ -367,6 +376,9 @@ void serial_rethink(void)
                if (serxdevice_enabled) {
                        sdr = 1;
                }
+               if (safe_receive) {
+                       sdr = 1;
+               }
                // RBF bit is not "sticky" but without it data can be lost when using fast emulation modes
                // and physical serial port or internally emulated serial devices.
                if (sdr) {
@@ -396,12 +408,24 @@ static TCHAR dochar(int v)
 
 static bool canreceive(void)
 {
-       if (!data_in_serdatr)
+       // don't replace data in SERDATR until interrupt is cleared in safe receive mode
+       if (safe_receive) {
+               if (intreq & (1 << 11)) {
+                       return false;
+               }
+               if (data_in_serdatr) {
+                       return false;
+               }
+       }
+       if (!data_in_serdatr) {
                return true;
-       if (currprefs.serial_direct)
+       }
+       if (currprefs.serial_direct) {
                return false;
-       if (currprefs.cpu_cycle_exact)
+       }
+       if (currprefs.cpu_cycle_exact) {
                return true;
+       }
        if (serdatr_last_got > SERIAL_HSYNC_BEFORE_OVERFLOW) {
 #if SERIALDEBUG > 0
                write_log(_T("SERIAL: OVERRUN\n"));
@@ -431,7 +455,6 @@ static void checkreceive_enet (void)
                serdatr |= 0x200;
        else
                serdatr |= 0x100;
-       serdatr_last_got = 0;
        serial_rx_irq();
 #if SERIALDEBUG > 2
        write_log (_T("SERIAL: received %02X (%c)\n"), serdatr & 0xff, dochar (serdatr));
@@ -570,7 +593,6 @@ static void checkreceive_serial (void)
                }
        }
 
-       serdatr_last_got = 0;
        serial_rx_irq();
 #if SERIALDEBUG > 2
        write_log(_T("SERIAL: received %02X (%c)\n"), serdatr & 0xff, dochar(serdatr));
@@ -781,34 +803,33 @@ static void serdatcopy(void)
        checksend();
 }
 
+
 void serial_hsynchandler (void)
 {
 #ifdef AHI
        extern void hsyncstuff(void);
        hsyncstuff();
 #endif
+       bool can = canreceive();
+
 #ifdef ARCADIA
        if (alg_flag || currprefs.genlock_image >= 7) {
-               if (data_in_serdatr) {
-                       return;
-               }
-               int ch = ld_serial_write();
-               if (ch >= 0) {
-                       serdatr = ch | 0x100;
-                       serdatr_last_got = 0;
-                       serial_rx_irq();
+               if (can) {
+                       int ch = ld_serial_write();
+                       if (ch >= 0) {
+                               serdatr = ch | 0x100;
+                               serial_rx_irq();
+                       }
                }
        }
 #endif
        if (cubo_enabled) {
-               if (data_in_serdatr) {
-                       return;
-               }
-               int ch = touch_serial_write();
-               if (ch >= 0) {
-                       serdatr = ch | 0x100;
-                       serdatr_last_got = 0;
-                       serial_rx_irq();
+               if (can) {
+                       int ch = touch_serial_write();
+                       if (ch >= 0) {
+                               serdatr = ch | 0x100;
+                               serial_rx_irq();
+                       }
                }
        }
        if (seriallog > 1 && !data_in_serdatr && gotlogwrite) {
@@ -824,7 +845,7 @@ void serial_hsynchandler (void)
        }
 #ifdef SERIAL_MAP
        if (sermap2 && sermap_enabled) {
-               if (!data_in_serdatr) {
+               if (can) {
                        for (;;) {
                                uae_u32 v = shmem_serial_receive();
                                if (v == 0xffffffff) {