From 7bd90170dc6db6703316056290d40a353df56c69 Mon Sep 17 00:00:00 2001
From: beeanyew <Bjorn Astrom>
Date: Fri, 4 Dec 2020 18:35:56 +0100
Subject: [PATCH] Add support for ROM mirroring

Confirmed to be working this way on a real Amiga, removes the need for separate ROM image maps in the config file for 256/512KB ROM images.
---
 config_file/config_file.c | 3 ++-
 config_file/config_file.h | 1 +
 default.cfg               | 6 ++----
 memory_mapped.c           | 4 ++--
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/config_file/config_file.c b/config_file/config_file.c
index b7eff98..31e06b4 100644
--- a/config_file/config_file.c
+++ b/config_file/config_file.c
@@ -212,12 +212,13 @@ void add_mapping(struct emulator_config *cfg, unsigned int type, unsigned int ad
       }
       fseek(in, 0, SEEK_SET);
       cfg->map_data[index] = (unsigned char *)calloc(1, cfg->map_size[index]);
+      cfg->rom_size[index] = (cfg->map_size[index] <= file_size) ? cfg->map_size[index] : file_size;
       if (!cfg->map_data[index]) {
         printf("ERROR: Unable to allocate memory for mapped ROM!\n");
         goto mapping_failed;
       }
       memset(cfg->map_data[index], 0x00, cfg->map_size[index]);
-      fread(cfg->map_data[index], (cfg->map_size[index] <= file_size) ? cfg->map_size[index] : file_size, 1, in);
+      fread(cfg->map_data[index], cfg->rom_size[index], 1, in);
       fclose(in);
       break;
     case MAPTYPE_REGISTER:
diff --git a/config_file/config_file.h b/config_file/config_file.h
index 6c56a68..272e910 100644
--- a/config_file/config_file.h
+++ b/config_file/config_file.h
@@ -49,6 +49,7 @@ struct emulator_config {
   unsigned char map_type[MAX_NUM_MAPPED_ITEMS];
   long map_offset[MAX_NUM_MAPPED_ITEMS];
   unsigned int map_size[MAX_NUM_MAPPED_ITEMS];
+  unsigned int rom_size[MAX_NUM_MAPPED_ITEMS];
   unsigned char *map_data[MAX_NUM_MAPPED_ITEMS];
   int map_mirror[MAX_NUM_MAPPED_ITEMS];
   char *map_id[MAX_NUM_MAPPED_ITEMS];
diff --git a/default.cfg b/default.cfg
index fd8a3fc..f92897b 100644
--- a/default.cfg
+++ b/default.cfg
@@ -1,11 +1,9 @@
 # Sets CPU type. Valid types are (probably) 68000, 68010, 68020, 68EC020, 68030, 68EC030, 68040, 68EC040, 68LC040 and some STTTT thing.
 cpu 68020
 # Map 512KB kickstart ROM to default offset.
-map type=rom address=0xF80000 size=0x80000 file=kick512.rom ovl=0
-# This is for mapping a 256KB kickstart ROM. I can probably add some additional thing about kicking this file into low/high area.
-#map type=rom address=0xFC0000 size=0x40000 file=kick256.rom ovl=0
+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=0x90000 file=cdtv.rom
+#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 Gayle as a register range.
diff --git a/memory_mapped.c b/memory_mapped.c
index c5a99e7..b77a8d2 100644
--- a/memory_mapped.c
+++ b/memory_mapped.c
@@ -27,9 +27,9 @@ int handle_mapped_read(struct emulator_config *cfg, unsigned int addr, unsigned
     switch(cfg->map_type[i]) {
       case MAPTYPE_ROM:
         if (CHKRANGE(addr, cfg->map_offset[i], cfg->map_size[i]))
-          read_addr = cfg->map_data[i] + (addr - cfg->map_offset[i]);
+          read_addr = cfg->map_data[i] + ((addr - cfg->map_offset[i]) % cfg->rom_size[i]);
         else if (cfg->map_mirror[i] != -1 && mirror && CHKRANGE(addr, cfg->map_mirror[i], cfg->map_size[i]))
-          read_addr = cfg->map_data[i] + (addr - cfg->map_mirror[i]);
+          read_addr = cfg->map_data[i] + ((addr - cfg->map_mirror[i]) % cfg->rom_size[i]);
         break;
       case MAPTYPE_RAM:
         if (CHKRANGE(addr, cfg->map_offset[i], cfg->map_size[i]))
-- 
2.39.2