esp.c: update esp_set_tc() to set STAT_TC flag

This flag is set once the transfer counter counts down to zero.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Helge Deller <deller@gmx.de>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20240112125420.514425-7-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

hw/scsi/esp.c

@@ -161,9 +161,15 @@ static uint32_t esp_get_tc(ESPState *s)
 
 static void esp_set_tc(ESPState *s, uint32_t dmalen)
 {
+    uint32_t old_tc = esp_get_tc(s);
+
     s->rregs[ESP_TCLO] = dmalen;
     s->rregs[ESP_TCMID] = dmalen >> 8;
     s->rregs[ESP_TCHI] = dmalen >> 16;
+
+    if (old_tc && dmalen == 0) {
+        s->rregs[ESP_RSTAT] |= STAT_TC;
+    }
 }
 
 static uint32_t esp_get_stc(ESPState *s)