[WIP] Add platforms, Z2 config file-based autoconf Fast

Makefile

@@ -1,6 +1,17 @@
 EXENAME          = emulator
 
-MAINFILES        = emulator.c Gayle.c ide.c memory_mapped.c config_file/config_file.c registers/registers_amiga.c input/input.c
+MAINFILES        = emulator.c \
+	Gayle.c \
+	ide.c \
+	memory_mapped.c \
+	config_file/config_file.c \
+	platforms/platforms.c \
+	platforms/amiga/amiga-autoconf.c \
+	platforms/amiga/amiga-platform.c \
+	platforms/amiga/amiga-registers.c \
+	platforms/dummy/dummy-platform.c \
+	platforms/dummy/dummy-registers.c
+
 MUSASHIFILES     = m68kcpu.c softfloat/softfloat.c 
 MUSASHIGENCFILES = m68kops.c
 MUSASHIGENHFILES = m68kops.h

config_file/config_file.c

@@ -1,4 +1,4 @@
-#include "config_file.h"
+#include "../platforms/platforms.h"
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -32,6 +32,7 @@ const char *config_item_names[CONFITEM_NUM] = {
   "loopcycles",
   "mouse",
   "keyboard",
+  "platform",
 };
 
 const char *mapcmd_names[MAPCMD_NUM] = {
@@ -227,7 +228,7 @@ void add_mapping(struct emulator_config *cfg, unsigned int type, unsigned int ad
       break;
   }
 
-  printf("[MAP %d] Added %s mapping for range %.8lX-%.8lX (%lX)\n", index, map_type_names[type], cfg->map_offset[index], cfg->map_offset[index] + cfg->map_size[index] - 1, (uint64_t)cfg->map_data[index]);
+  printf("[MAP %d] Added %s mapping for range %.8lX-%.8lX ID: %s\n", index, map_type_names[type], cfg->map_offset[index], cfg->map_offset[index] + cfg->map_size[index] - 1, cfg->map_id[index] ? cfg->map_id[index] : "None");
 
   return;
 
@@ -352,6 +353,19 @@ struct emulator_config *load_config_file(char *filename) {
         cfg->keyboard_toggle_key = cur_cmd[0];
         printf("Enabled keyboard event forwarding, toggle key %c.\n", cfg->keyboard_toggle_key);
         break;
+      case CONFITEM_PLATFORM: {
+        char platform_name[128], platform_sub[128];
+        memset(platform_name, 0x00, 128);
+        memset(platform_sub, 0x00, 128);
+        get_next_string(parse_line, platform_name, &str_pos, ' ');
+        printf("Setting platform to %s", platform_name);
+        get_next_string(parse_line, platform_sub, &str_pos, ' ');
+        if (strlen(platform_sub))
+          printf(" (sub: %s)", platform_sub);
+        printf("\n");
+        cfg->platform = make_platform_config(platform_name, platform_sub);
+        break;
+      }
       case CONFITEM_NONE:
       default:
         printf("Unknown config item %s on line %d.\n", cur_cmd, cur_line);
@@ -379,3 +393,17 @@ struct emulator_config *load_config_file(char *filename) {
 
   return cfg;
 }
+
+int get_named_mapped_item(struct emulator_config *cfg, char *name) {
+  if (strlen(name) == 0)
+    return -1;
+
+  for (int i = 0; i < MAX_NUM_MAPPED_ITEMS; i++) {
+    if (cfg->map_type[i] == MAPTYPE_NONE || !cfg->map_id[i])
+      continue;
+    if (strcmp(name, cfg->map_id[i]) == 0)
+      return i;
+  }
+
+  return -1;
+}

config_file/config_file.h

@@ -32,6 +32,7 @@ typedef enum {
   CONFITEM_LOOPCYCLES,
   CONFITEM_MOUSE,
   CONFITEM_KEYBOARD,
+  CONFITEM_PLATFORM,
   CONFITEM_NUM,
 } config_items;
 
@@ -54,6 +55,8 @@ struct emulator_config {
   int map_mirror[MAX_NUM_MAPPED_ITEMS];
   char *map_id[MAX_NUM_MAPPED_ITEMS];
 
+  struct platform_config *platform;
+
   char *mouse_file;
 
   char mouse_toggle_key, keyboard_toggle_key;
@@ -62,10 +65,22 @@ struct emulator_config {
   unsigned int loop_cycles;
 };
 
+struct platform_config {
+  char *subsys;
+
+  int (*custom_read)(struct emulator_config *cfg, unsigned int addr, unsigned int *val, unsigned char type);
+  int (*custom_write)(struct emulator_config *cfg, unsigned int addr, unsigned int val, unsigned char type);
+
+  int (*register_read)(unsigned int addr, unsigned char type, unsigned int *val);
+  int (*register_write)(unsigned int addr, unsigned int value, unsigned char type);
+
+  int (*platform_initial_setup)(struct emulator_config *cfg);
+  void (*setvar)(char *var, char *val);
+};
+
 unsigned int get_m68k_cpu_type(char *name);
 struct emulator_config *load_config_file(char *filename);
 
 int handle_mapped_read(struct emulator_config *cfg, unsigned int addr, unsigned int *val, unsigned char type, unsigned char mirror);
 int handle_mapped_write(struct emulator_config *cfg, unsigned int addr, unsigned int value, unsigned char type, unsigned char mirror);
-int handle_register_read(unsigned int addr, unsigned char type, unsigned int *val);
-int handle_register_write(unsigned int addr, unsigned int value, unsigned char type);
+int get_named_mapped_item(struct emulator_config *cfg, char *name);

default.cfg

@@ -4,12 +4,26 @@ cpu 68020
 map type=rom address=0xF80000 size=0x80000 file=kick.rom ovl=0
 # Want to map an extended ROM, such as CDTV or CD32?
 #map type=rom address=0xF00000 size=0x80000 file=cdtv.rom
-# Map 256MB of Fast RAM at 0x8000000.
-map type=ram address=0x08000000 size=128M
+
+# Map 128MB of Fast RAM at 0x8000000.
+map type=ram address=0x08000000 size=128M id=cpu_slot_ram
+# 128MB of Z3 Fast at the first proper address
+#map type=ram address=0x10000000 size=128M id=z3_autoconf_fast
+# Max 8MB of Z2 Fast can be mapped due to addressing space limitations, but for instance 2+4MB can be chained to leave 2MB for something else.
+map type=ram address=0x200000 size=8M id=z2_autoconf_fast
+#map type=ram address=0x200000 size=2M id=z2_autoconf_fast
+#map type=ram address=0x400000 size=4M id=z2_autoconf_fast
+
+# This is fake Chip RAM, do not use on a real Amiga.
+#map type=ram address=0x0 size=2M
+
 # Map Gayle as a register range.
 map type=register address=0xD80000 size=0x70000
 # Number of instructions to run every main loop.
 loopcycles 300
+# Set the platform to Amiga to enable all the registers and stuff.
+platform amiga
+
 # Forward mouse events to host system, defaults to off unless toggle key is pressed on the Pi.
 # Syntax is mouse [device] [toggle key]
 #mouse /dev/input/mouse0 m

emulator.c

@@ -18,7 +18,7 @@
 #include "ide.h"
 #include "m68k.h"
 #include "main.h"
-#include "config_file/config_file.h"
+#include "platforms/platforms.h"
 #include "input/input.h"
 
 //#define BCM2708_PERI_BASE        0x20000000  //pi0-1
@@ -228,6 +228,10 @@ int main(int argc, char *argv[]) {
   if (cfg) {
     if (cfg->cpu_type) cpu_type = cfg->cpu_type;
     if (cfg->loop_cycles) loop_cycles = cfg->loop_cycles;
+
+    if (!cfg->platform)
+      cfg->platform = make_platform_config("none", "generic");
+    cfg->platform->platform_initial_setup(cfg);
   }
 
   if (cfg->mouse_enabled) {
@@ -450,6 +454,10 @@ int cpu_irq_ack(int level) {
 static unsigned int target = 0;
 
 unsigned int m68k_read_memory_8(unsigned int address) {
+  if (cfg->platform->custom_read && cfg->platform->custom_read(cfg, address, &target, OP_TYPE_BYTE) != -1) {
+    return target;
+  }
+
   if (cfg) {
     int ret = handle_mapped_read(cfg, address, &target, OP_TYPE_BYTE, ovl);
     if (ret != -1)
@@ -465,6 +473,10 @@ unsigned int m68k_read_memory_8(unsigned int address) {
 }
 
 unsigned int m68k_read_memory_16(unsigned int address) {
+  if (cfg->platform->custom_read && cfg->platform->custom_read(cfg, address, &target, OP_TYPE_WORD) != -1) {
+    return target;
+  }
+
   if (cfg) {
     int ret = handle_mapped_read(cfg, address, &target, OP_TYPE_WORD, ovl);
     if (ret != -1)
@@ -507,6 +519,10 @@ unsigned int m68k_read_memory_16(unsigned int address) {
 }
 
 unsigned int m68k_read_memory_32(unsigned int address) {
+  if (cfg->platform->custom_read && cfg->platform->custom_read(cfg, address, &target, OP_TYPE_LONGWORD) != -1) {
+    return target;
+  }
+
   if (cfg) {
     int ret = handle_mapped_read(cfg, address, &target, OP_TYPE_LONGWORD, ovl);
     if (ret != -1)
@@ -524,6 +540,10 @@ unsigned int m68k_read_memory_32(unsigned int address) {
 }
 
 void m68k_write_memory_8(unsigned int address, unsigned int value) {
+  if (cfg->platform->custom_write && cfg->platform->custom_write(cfg, address, value, OP_TYPE_BYTE) != -1) {
+    return;
+  }
+
   if (cfg) {
     int ret = handle_mapped_write(cfg, address, value, OP_TYPE_BYTE, ovl);
     if (ret != -1)
@@ -545,6 +565,10 @@ void m68k_write_memory_8(unsigned int address, unsigned int value) {
 }
 
 void m68k_write_memory_16(unsigned int address, unsigned int value) {
+  if (cfg->platform->custom_write && cfg->platform->custom_write(cfg, address, value, OP_TYPE_WORD) != -1) {
+    return;
+  }
+
   if (cfg) {
     int ret = handle_mapped_write(cfg, address, value, OP_TYPE_WORD, ovl);
     if (ret != -1)
@@ -560,6 +584,10 @@ void m68k_write_memory_16(unsigned int address, unsigned int value) {
 }
 
 void m68k_write_memory_32(unsigned int address, unsigned int value) {
+  if (cfg->platform->custom_write && cfg->platform->custom_write(cfg, address, value, OP_TYPE_LONGWORD) != -1) {
+    return;
+  }
+
   if (cfg) {
     int ret = handle_mapped_write(cfg, address, value, OP_TYPE_LONGWORD, ovl);
     if (ret != -1)

memory_mapped.c

@@ -45,9 +45,11 @@ int handle_mapped_read(struct emulator_config *cfg, unsigned int addr, unsigned
       continue;
     
     if (handle_regs) {
-      if (handle_register_read(addr, type, &target) != -1) {
-        *val = target;
-        return 1;
+      if (cfg->platform && cfg->platform->register_read) {
+        if (cfg->platform->register_read(addr, type, &target) != -1) {
+          *val = target;
+          return 1;
+        }
       }
       return -1;
     }
@@ -109,7 +111,9 @@ int handle_mapped_write(struct emulator_config *cfg, unsigned int addr, unsigned
       continue;
     
     if (handle_regs) {
-      return handle_register_write(addr, value, type);
+      if (cfg->platform && cfg->platform->register_write) {
+        return cfg->platform->register_write(addr, value, type);
+      }
     }
     else if (write_addr) {
       //printf("[PC: %.8X] Write %s to %s (%.8X) (%d)\n", m68k_get_reg(NULL, M68K_REG_PC), op_type_names[type], map_type_names[cfg->map_type[i]], addr, mirror);

platforms/amiga/amiga-autoconf.c

@@ -0,0 +1,119 @@
+#include "../platforms.h"
+#include "amiga-autoconf.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static unsigned char ac_fast_ram_rom[] = {
+    0xe, AC_MEM_SIZE_8MB,                   // 00/02, link into memory free list, 8 MB
+    0x6, 0x9,                               // 04/06, product id
+    0x8, 0x0,                               // 08/0a, preference to 8 MB space
+    0x0, 0x0,                               // 0c/0e, reserved
+    0x0, 0x7, 0xd, 0xb,                     // 10/12/14/16, mfg id
+    0x0, 0x0, 0x0, 0x0, 0x0, 0x4, 0x2, 0x0  // 18/.../26, serial
+};
+
+static unsigned char ac_a314_rom[] = {
+    0xc, AC_MEM_SIZE_64KB,                  // 00/02, 64 kB
+    0xa, 0x3,                               // 04/06, product id
+    0x0, 0x0,                               // 08/0a, any space okay
+    0x0, 0x0,                               // 0c/0e, reserved
+    0x0, 0x7, 0xd, 0xb,                     // 10/12/14/16, mfg id
+    0xa, 0x3, 0x1, 0x4, 0x0, 0x0, 0x0, 0x0  // 18/.../26, serial
+};
+
+int ac_current_pic = 0;
+int ac_pic_count = 0;
+int ac_done = 0;
+int ac_type[AC_PIC_LIMIT];
+int ac_index[AC_PIC_LIMIT];
+unsigned int ac_base[AC_PIC_LIMIT];
+
+unsigned char get_autoconf_size(int size) {
+  if (size == 8 * SIZE_MEGA)
+    return AC_MEM_SIZE_8MB;
+  if (size == 4 * SIZE_MEGA)
+    return AC_MEM_SIZE_4MB;
+  if (size == 2 * SIZE_MEGA)
+    return AC_MEM_SIZE_2MB;
+  else
+    return AC_MEM_SIZE_64KB;
+}
+
+unsigned int autoconfig_read_memory_8(struct emulator_config *cfg, unsigned int address_) {
+  unsigned char *rom = NULL;
+  int address = address_ - AC_BASE;
+  unsigned char val = 0;
+
+  switch(ac_type[ac_current_pic]) {
+    case ACTYPE_MAPFAST_Z2:
+      rom = ac_fast_ram_rom;
+      break;
+    case ACTYPE_A314:
+      rom = ac_a314_rom;
+      break;
+    default:
+      return 0;
+      break;
+  }
+
+  
+  if ((address & 1) == 0 && (address / 2) < (int)sizeof(ac_fast_ram_rom)) {
+    if (ac_type[ac_current_pic] == ACTYPE_MAPFAST_Z2 && address / 2 == 1)
+      val = get_autoconf_size(cfg->map_size[ac_index[ac_current_pic]]);
+    else
+      val = rom[address / 2];
+    //printf("Read byte %d from autoconf for PIC %d (%.2X).\n", address/2, ac_current_pic, val);
+  }
+  val <<= 4;
+  if (address != 0 && address != 2 && address != 40 && address != 42)
+    val ^= 0xf0;
+  
+  return (unsigned int)val;
+}
+
+void autoconfig_write_memory_8(struct emulator_config *cfg, unsigned int address_, unsigned int value) {
+  int address = address_ - AC_BASE;
+  int done = 0;
+
+  unsigned int *base = NULL;
+
+  switch(ac_type[ac_current_pic]) {
+    case ACTYPE_MAPFAST_Z2:
+      base = &ac_base[ac_current_pic];
+      break;
+    case ACTYPE_A314:
+      //base = &a314_base;
+      break;
+    default:
+      break;
+  }
+
+  if (!base) {
+    printf("Failed to set up the base for autoconfig PIC %d.\n", ac_current_pic);
+    done = 1;
+  }
+  else {
+    if (address == 0x4a) {  // base[19:16]
+      *base = (value & 0xf0) << (16 - 4);
+    } else if (address == 0x48) {  // base[23:20]
+      *base &= 0xff0fffff;
+      *base |= (value & 0xf0) << (20 - 4);
+
+      if (ac_type[ac_current_pic] == ACTYPE_MAPFAST_Z2) { // fast ram
+        //a314_set_mem_base_size(*base, cfg->map_size[ac_index[ac_current_pic]]);
+      }
+      done = 1;
+    } else if (address == 0x4c) {  // shut up
+      done = 1;
+    }
+  }
+
+  if (done) {
+    //printf("Address of Z2 autoconf RAM changed to %.8x\n", ac_base[ac_current_pic]);
+    cfg->map_offset[ac_index[ac_current_pic]] = ac_base[ac_current_pic];
+    ac_current_pic++;
+    if (ac_current_pic == ac_pic_count)
+      ac_done = 1;
+  }
+}

platforms/amiga/amiga-autoconf.h

@@ -0,0 +1,22 @@
+#define AC_BASE 0xE80000
+#define AC_SIZE (64 * 1024)
+#define AC_PIC_LIMIT 8
+
+#define AC_MEM_SIZE_8MB 0
+#define AC_MEM_SIZE_64KB 1
+#define AC_MEM_SIZE_128KB 2
+#define AC_MEM_SIZE_256KB 3
+#define AC_MEM_SIZE_512KB 4
+#define AC_MEM_SIZE_1MB 5
+#define AC_MEM_SIZE_2MB 6
+#define AC_MEM_SIZE_4MB 7
+
+enum autoconf_types {
+    ACTYPE_MAPFAST_Z2,
+    ACTYPE_MAPFAST_Z3,
+    ACTYPE_A314,
+    ACTYPE_NUM,
+};
+
+unsigned int autoconfig_read_memory_8(struct emulator_config *cfg, unsigned int address);
+void autoconfig_write_memory_8(struct emulator_config *cfg, unsigned int address, unsigned int value);

platforms/amiga/amiga-platform.c

@@ -0,0 +1,119 @@
+#include "../platforms.h"
+#include "amiga-autoconf.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int handle_register_read_amiga(unsigned int addr, unsigned char type, unsigned int *val);
+int handle_register_write_amiga(unsigned int addr, unsigned int value, unsigned char type);
+
+extern int ac_done;
+extern int ac_pic_count;
+extern int ac_type[AC_PIC_LIMIT];
+extern int ac_index[AC_PIC_LIMIT];
+
+const char *z2_autoconf_id = "z2_autoconf_fast";
+const char *z2_autoconf_zap_id = "^2_autoconf_fast";
+
+int custom_read_amiga(struct emulator_config *cfg, unsigned int addr, unsigned int *val, unsigned char type) {
+    if (!ac_done && addr >= AC_BASE && addr < AC_BASE + AC_SIZE) {
+        if (ac_pic_count == 0) {
+            ac_done = 1;
+            return -1;
+        }
+
+        if (type == OP_TYPE_BYTE) {
+            //printf("Read from autoconf area.\n");
+            *val = autoconfig_read_memory_8(cfg, addr);
+            return 1;
+        }
+    }
+
+    return -1;
+}
+
+int custom_write_amiga(struct emulator_config *cfg, unsigned int addr, unsigned int val, unsigned char type) {
+    if (cfg || addr || val || type) {}
+    if (!ac_done && addr >= AC_BASE && addr < AC_BASE + AC_SIZE) {
+        if (type == OP_TYPE_BYTE) {
+            if (ac_pic_count == 0) {
+                ac_done = 1;
+                return -1;
+            }
+
+            //printf("Write to autoconf area.\n");
+            autoconfig_write_memory_8(cfg, addr, val);
+            return 1;
+        }
+    }
+
+    return -1;
+}
+
+int setup_platform_amiga(struct emulator_config *cfg) {
+    if (cfg) {}
+    printf("Performing setup for Amiga platform.\n");
+    // Look for Z2 autoconf Fast RAM by id
+    int index = get_named_mapped_item(cfg, "z2_autoconf_fast");
+    more_z2_fast:;
+    if (index != -1) {
+        cfg->map_id[index][0] = '^';
+        int resize_data = 0;
+        if (cfg->map_size[index] > 8 * SIZE_MEGA) {
+            printf("Attempted to configure more than 8MB of Z2 Fast RAM, downsizng to 8MB.\n");
+            resize_data = 8 * SIZE_MEGA;
+        }
+        else if(cfg->map_size[index] != 2 * SIZE_MEGA && cfg->map_size[index] != 4 * SIZE_MEGA && cfg->map_size[index] != 8 * SIZE_MEGA) {
+            printf("Z2 Fast RAM may only provision 2, 4 or 8MB of memory, resizing to ");
+            if (cfg->map_size[index] > 8 * SIZE_MEGA)
+                resize_data = 8 * SIZE_MEGA;
+            else if (cfg->map_size[index] > 4 * SIZE_MEGA)
+                resize_data = 4 * SIZE_MEGA;
+            else
+                resize_data = 2 * SIZE_MEGA;
+            printf("%dMB.\n", resize_data / SIZE_MEGA);
+        }
+        if (resize_data) {
+            free(cfg->map_data[index]);
+            cfg->map_size[index] = resize_data;
+            cfg->map_data[index] = (unsigned char *)malloc(cfg->map_size[index]);
+        }
+        printf("%dMB of Z2 Fast RAM configured at $%lx\n", cfg->map_size[index] / SIZE_MEGA, cfg->map_offset[index]);
+        ac_type[ac_pic_count] = ACTYPE_MAPFAST_Z2;
+        ac_index[ac_pic_count] = index;
+        ac_pic_count++;
+        printf("AAAAHH!\n");
+    }
+    else
+        printf("No Z2 Fast RAM configured.\n");
+    index = get_named_mapped_item(cfg, "z2_autoconf_fast");
+    if (index != -1)
+        goto more_z2_fast;
+    
+    for (int i = 0; i < MAX_NUM_MAPPED_ITEMS; i ++) {
+        if (cfg->map_id[i] && strcmp(cfg->map_id[i], z2_autoconf_zap_id) == 0) {
+            cfg->map_id[i][0] = 'z';
+        }
+    }
+    
+    return 0;
+}
+
+void setvar_amiga(char *var, char *val) {
+    if (var || val) {}
+}
+
+void create_platform_amiga(struct platform_config *cfg, char *subsys) {
+    cfg->register_read = handle_register_read_amiga;
+    cfg->register_write = handle_register_write_amiga;
+    cfg->custom_read = custom_read_amiga;
+    cfg->custom_write = custom_write_amiga;
+    cfg->platform_initial_setup = setup_platform_amiga;
+
+    cfg->setvar = setvar_amiga;
+
+    if (subsys) {
+        cfg->subsys = malloc(strlen(subsys) + 1);
+        strcpy(cfg->subsys, subsys);
+    }
+}

platforms/amiga/amiga-registers.c

@@ -1,10 +1,10 @@
-#include "../Gayle.h"
-#include "../config_file/config_file.h"
+#include "../../Gayle.h"
+#include "../../config_file/config_file.h"
 
 #define GAYLEBASE 0xD80000  // D7FFFF
 #define GAYLESIZE 0x6FFFF
 
-int handle_register_read(unsigned int addr, unsigned char type, unsigned int *val) {
+int handle_register_read_amiga(unsigned int addr, unsigned char type, unsigned int *val) {
     if (addr > GAYLEBASE && addr < GAYLEBASE + GAYLESIZE) {
         switch(type) {
         case OP_TYPE_BYTE:
@@ -27,7 +27,7 @@ int handle_register_read(unsigned int addr, unsigned char type, unsigned int *va
     return -1;
 }
 
-int handle_register_write(unsigned int addr, unsigned int value, unsigned char type) {
+int handle_register_write_amiga(unsigned int addr, unsigned int value, unsigned char type) {
     if (addr > GAYLEBASE && addr < GAYLEBASE + GAYLESIZE) {
         switch(type) {
         case OP_TYPE_BYTE:

platforms/dummy/dummy-platform.c

@@ -0,0 +1,24 @@
+#include "../platforms.h"
+#include <stdlib.h>
+#include <string.h>
+
+int handle_register_read_dummy(unsigned int addr, unsigned char type, unsigned int *val);
+int handle_register_write_dummy(unsigned int addr, unsigned int value, unsigned char type);
+
+int setup_platform_dummy(struct emulator_config *cfg) {
+    if (cfg) {}
+    return 0;
+}
+
+void create_platform_dummy(struct platform_config *cfg, char *subsys) {
+    cfg->custom_read = NULL;
+    cfg->custom_write = NULL;
+    cfg->register_read = handle_register_read_dummy;
+    cfg->register_write = handle_register_write_dummy;
+    cfg->platform_initial_setup = setup_platform_dummy;
+
+    if (subsys) {
+        cfg->subsys = malloc(strlen(subsys) + 1);
+        strcpy(cfg->subsys, subsys);
+    }
+}

platforms/dummy/dummy-registers.c

@@ -0,0 +1,13 @@
+int handle_register_read_dummy(unsigned int addr, unsigned char type, unsigned int *val) {
+    if (addr) {}
+    if (type) {}
+    if (val) {}
+    return -1;
+}
+
+int handle_register_write_dummy(unsigned int addr, unsigned int value, unsigned char type) {
+    if (addr) {}
+    if (type) {}
+    if (value) {}
+    return -1;
+}

platforms/platforms.c

@@ -0,0 +1,60 @@
+#include "platforms.h"
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+static char*platform_names[PLATFORM_NUM] = {
+    "none",
+    "amiga",
+    "mac68k",
+    "x68000",
+};
+
+int get_platform_index(char *name) {
+    if (!name || strlen(name) == 0)
+        return -1;
+
+    for (int i = 0; i < PLATFORM_NUM; i++) {
+        if (strcmp(name, platform_names[i]) == 0)
+            return i;
+    }
+    return -1;
+}
+
+void create_platform_amiga(struct platform_config *cfg, char *subsys);
+void create_platform_dummy(struct platform_config *cfg, char *subsys);
+
+struct platform_config *make_platform_config(char *name, char *subsys) {
+    struct platform_config *cfg = NULL;
+    int platform_id = get_platform_index(name);
+
+    if (platform_id == -1) {
+        // Display a warning if no match is found for the config name, in case it was mistyped.
+        printf("No match found for platform name \'%s\', defaulting to none/generic.\n", name);
+        platform_id = PLATFORM_NONE;
+    }
+    else {
+        printf("Creating platform config for %s...\n", name);
+    }
+
+    cfg = (struct platform_config *)malloc(sizeof(struct platform_config));
+    if (!cfg) {
+        printf("Failed to allocate memory for new platform config!.\n");
+        return NULL;
+    }
+    memset(cfg, 0x00, sizeof(struct platform_config));
+
+    switch(platform_id) {
+        case PLATFORM_AMIGA:
+            create_platform_amiga(cfg, subsys);
+            break;
+        case PLATFORM_NONE:
+        case PLATFORM_MAC:
+        case PLATFORM_X68000:
+        default:
+            create_platform_dummy(cfg, subsys);
+            break;
+    }
+
+    return cfg;
+}

platforms/platforms.h

@@ -0,0 +1,11 @@
+#include "../config_file/config_file.h"
+
+enum base_platforms {
+    PLATFORM_NONE,
+    PLATFORM_AMIGA,
+    PLATFORM_MAC,
+    PLATFORM_X68000,
+    PLATFORM_NUM,
+};
+
+struct platform_config *make_platform_config(char *name, char *subsys);

registers/registers_dummy.c

@@ -1,7 +0,0 @@
-int handle_register_read(unsigned int addr, unsigned char type) {
-    return -1;
-}
-
-int handle_register_write(unsigned int addr, unsigned char type) {
-    return -1;
-}