From cee8fa0ae40287561be6dda9677aeeb76be1af1e Mon Sep 17 00:00:00 2001
From: Jasmine Iwanek <jasmine@iwanek.co.uk>
Date: Mon, 22 Sep 2025 00:22:32 -0400
Subject: [PATCH] Allow PCjr FDC to be disabled

---
 src/include/86box/m_pcjr.h  |  3 +++
 src/machine/m_pcjr.c        | 10 +++++++++-
 src/machine/machine_table.c |  4 ++--
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/src/include/86box/m_pcjr.h b/src/include/86box/m_pcjr.h
index 6fb0ee2ed..9b4a7cbaf 100644
--- a/src/include/86box/m_pcjr.h
+++ b/src/include/86box/m_pcjr.h
@@ -66,6 +66,9 @@ typedef struct pcjr_s {
     int        serial_pos;
     uint8_t    pa;
     uint8_t    pb;
+
+    uint8_t    option_fdc;
+
     pc_timer_t send_delay_timer;
 
 } pcjr_t; 
diff --git a/src/machine/m_pcjr.c b/src/machine/m_pcjr.c
index 519933b23..c1b7aba9b 100644
--- a/src/machine/m_pcjr.c
+++ b/src/machine/m_pcjr.c
@@ -41,6 +41,7 @@
 #include <86box/rom.h>
 #include <86box/fdd.h>
 #include <86box/fdc.h>
+#include <86box/fdc_ext.h>
 #include <86box/sound.h>
 #include <86box/snd_speaker.h>
 #include <86box/snd_sn76489.h>
@@ -653,6 +654,8 @@ kbd_read(uint16_t port, void *priv)
         case 0x62:
             ret = (pcjr->latched ? 1 : 0);
             ret |= 0x02; /* Modem card not installed */
+            if (!pcjr->option_fdc)
+                ret |= 0x04; /* Diskette card not installed */
             if (mem_size < 128)
                 ret |= 0x08; /* 64k expansion card not installed */
             if ((pcjr->pb & 0x08) || (cassette == NULL))
@@ -846,6 +849,8 @@ machine_pcjr_init(UNUSED(const machine_t *model))
 
     pcjr = calloc(1, sizeof(pcjr_t));
 
+    pcjr->option_fdc = 0;
+
     is_pcjr = 1;
 
     pic_init_pcjr();
@@ -877,7 +882,10 @@ machine_pcjr_init(UNUSED(const machine_t *model))
 
     nmi_mask = 0x80;
 
-    device_add(&fdc_pcjr_device);
+    if (fdc_current[0] == FDC_INTERNAL) {
+        device_add(&fdc_pcjr_device);
+        pcjr->option_fdc = 1;
+    }
 
     device_add(&ns8250_pcjr_device);
     /* So that serial_standalone_init() won't do anything. */
diff --git a/src/machine/machine_table.c b/src/machine/machine_table.c
index 6bb120b03..8816ce42c 100644
--- a/src/machine/machine_table.c
+++ b/src/machine/machine_table.c
@@ -300,7 +300,7 @@ const machine_t machines[] = {
             .max_multi   = 0
         },
         .bus_flags = MACHINE_PCJR,
-        .flags     = MACHINE_VIDEO_FIXED | MACHINE_KEYBOARD | MACHINE_CARTRIDGE,
+        .flags     = MACHINE_VIDEO_FIXED | MACHINE_KEYBOARD | MACHINE_CARTRIDGE | MACHINE_FDC,
         .ram       = {
             .min  = 64,
             .max  = 640,
@@ -316,7 +316,7 @@ const machine_t machines[] = {
         .gpio_acpi                = 0xffffffff,
         .device                   = NULL,
         .kbd_device               = NULL,
-        .fdc_device               = NULL,
+        .fdc_device               = &fdc_pcjr_device,
         .sio_device               = NULL,
         .vid_device               = &pcjr_device,
         .snd_device               = NULL,