Improve machine availability checking so that it absolutely never uses the legacy method if the machine has a device and the device has a CONFIG_BIOS setting.

src/device.c

@@ -390,37 +390,18 @@ device_get_priv(const device_t *dev)
 int
 device_available(const device_t *dev)
 {
-    if (dev != NULL) {
+    int ret = machine_device_available(dev);
-        const device_config_t *config = dev->config;
-        if ((config != NULL) && (config->type == CONFIG_BIOS)) {
-            int roms_present = 0;
-            const device_config_bios_t *bios = (const device_config_bios_t *) config->bios;
-
-            /* Go through the ROM's in the device configuration. */
-            while ((bios != NULL) &&
-                   (bios->name != NULL) &&
-                   (bios->internal_name != NULL) &&
-                   (bios->files_no != 0)) {
-                int i = 0;
-                for (uint8_t bf = 0; bf < bios->files_no; bf++)
-                    i += !!rom_present(bios->files[bf]);
-                if (i == bios->files_no)
-                    roms_present++;
-                bios++;
-            }
-
-            return (roms_present ? -1 : 0);
-        }
 
+    if (ret == 0) {
         /* No CONFIG_BIOS field present, use the classic available(). */
         if (dev->available != NULL)
-            return (dev->available());
+            ret = (dev->available());
         else
-            return 1;
+            ret = (dev != NULL);
-    }
+    } else
+        ret = (ret == -1);
 
-    /* A NULL device is never available. */
+    return ret;
-    return 0;
 }
 
 uint8_t
@@ -964,6 +945,36 @@ machine_get_config_string(char *str)
     return ret;
 }
 
+int
+machine_device_available(const device_t *dev)
+{
+    if (dev != NULL) {
+        const device_config_t *config = dev->config;
+        if ((config != NULL) && (config->type == CONFIG_BIOS)) {
+            int roms_present = 0;
+            const device_config_bios_t *bios = (const device_config_bios_t *) config->bios;
+
+            /* Go through the ROM's in the device configuration. */
+            while ((bios != NULL) &&
+                   (bios->name != NULL) &&
+                   (bios->internal_name != NULL) &&
+                   (bios->files_no != 0)) {
+                int i = 0;
+                for (uint8_t bf = 0; bf < bios->files_no; bf++)
+                    i += !!rom_present(bios->files[bf]);
+                if (i == bios->files_no)
+                    roms_present++;
+                bios++;
+            }
+
+            return (roms_present ? -1 : -2);
+        }
+    }
+
+    /* NULL device or no CONFIG_BIOS field, return 0. */
+    return 0;
+}
+
 const device_t *
 device_context_get_device(void)
 {

src/include/86box/device.h

@@ -239,6 +239,8 @@ extern const char *device_get_internal_name(const device_t *dev);
 extern int         machine_get_config_int(char *str);
 extern const char *machine_get_config_string(char *str);
 
+extern int         machine_device_available(const device_t *dev);
+
 extern const device_t device_none;
 extern const device_t device_internal;
 

src/machine/machine.c

@@ -139,18 +139,24 @@ machine_init(void)
 int
 machine_available(int m)
 {
-    int             ret;
+    int             ret = 0;
     const device_t *dev = machine_get_device(m);
 
-    bios_only = 1;
+    if (dev != NULL)
+        ret = machine_device_available(dev);
+    /*
+       Only via machine_init_ex() if the device is NULL or
+       it lacks a CONFIG_BIOS field (or the CONFIG_BIOS field
+       is not the first in list.
+     */
+    if (ret == 0) {
+        bios_only = 1;
 
-    ret = device_available(dev);
-    /* Do not check via machine_init_ex() if the device is not NULL and
-       it has a CONFIG_BIOS field. */
-    if ((dev == NULL) || (ret != -1))
         ret = machine_init_ex(m);
 
-    bios_only = 0;
+        bios_only = 0;
+    } else if (ret == -2)
+        ret = 0;
 
     return !!ret;
 }