From fb267d1f8b4a51bdb1f552f5b7bd22e498443c16 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Thu, 13 Jun 2024 19:01:57 +0200
Subject: [PATCH] Fix the DP8473 FDC flags, closes #4538.

---
 src/floppy/fdc.c        | 14 +++++++++++++-
 src/include/86box/fdc.h |  1 +
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/floppy/fdc.c b/src/floppy/fdc.c
index 1a0aa2f10..4c1170eb9 100644
--- a/src/floppy/fdc.c
+++ b/src/floppy/fdc.c
@@ -931,6 +931,10 @@ fdc_write(uint16_t addr, uint8_t val, void *priv)
                         fdc->format_state = 0;
                         break;
                     case 0x0e: /*Dump registers*/
+                        if (fdc->flags & FDC_FLAG_NEC) {
+                            fdc_bad_command(fdc);
+                            break;
+                        }
                         fdc->lastdrive = fdc->drive;
                         fdc->interrupt = 0x0e;
                         fdc_callback(fdc);
@@ -949,6 +953,10 @@ fdc_write(uint16_t addr, uint8_t val, void *priv)
                     case 0x10: /*Get version*/
                     case 0x14: /*Unlock*/
                     case 0x94: /*Lock*/
+                        if (fdc->flags & FDC_FLAG_NEC) {
+                            fdc_bad_command(fdc);
+                            break;
+                        }
                         fdc->lastdrive = fdc->drive;
                         fdc->interrupt = fdc->command;
                         fdc_callback(fdc);
@@ -962,6 +970,10 @@ fdc_write(uint16_t addr, uint8_t val, void *priv)
                             fdc_bad_command(fdc);
                         break;
                     case 0x13: /*Configure*/
+                        if (fdc->flags & FDC_FLAG_NEC) {
+                            fdc_bad_command(fdc);
+                            break;
+                        }
                         fdc->pnum = 0;
                         fdc->ptot = 3;
                         fdc->stat |= 0x90;
@@ -2682,7 +2694,7 @@ const device_t fdc_dp8473_device = {
     .name          = "NS DP8473 Floppy Drive Controller",
     .internal_name = "fdc_dp8473",
     .flags         = 0,
-    .local         = FDC_FLAG_AT | FDC_FLAG_NSC,
+    .local         = FDC_FLAG_AT | FDC_FLAG_NEC | FDC_FLAG_NO_DSR_RESET,
     .init          = fdc_init,
     .close         = fdc_close,
     .reset         = fdc_reset,
diff --git a/src/include/86box/fdc.h b/src/include/86box/fdc.h
index 9529fde5c..6bb8f081e 100644
--- a/src/include/86box/fdc.h
+++ b/src/include/86box/fdc.h
@@ -57,6 +57,7 @@ extern int fdc_type;
 #define FDC_FLAG_QUA            0x3000 /* Is Quaternary */
 #define FDC_FLAG_CHANNEL        0x3000 /* Channel mask */
 #define FDC_FLAG_NO_DSR_RESET   0x4000 /* Has no DSR reset */
+#define FDC_FLAG_NEC            0x8000 /* Is NEC upd765-compatible */
 
 typedef struct fdc_t {
     uint8_t dor;