From d37dc725c6752696cbf1621d87966cbbd738d101 Mon Sep 17 00:00:00 2001
From: Anthony Pesch <inolen@gmail.com>
Date: Thu, 20 Jul 2017 20:06:50 -0400
Subject: [PATCH] initial widescreen patching support

---
 CMakeLists.txt            |  1 +
 src/emulator.c            |  9 +---
 src/guest/aica/aica.c     |  2 +-
 src/guest/arm7/arm7.c     |  2 +-
 src/guest/bios/bios.c     | 19 +++------
 src/guest/dreamcast.c     |  1 +
 src/guest/gdrom/cdi.c     | 65 +++++++++++-----------------
 src/guest/gdrom/disc.c    | 90 +++++++++++++++++++++++++--------------
 src/guest/gdrom/disc.h    | 18 ++++++--
 src/guest/gdrom/gdi.c     | 43 +++++++------------
 src/guest/gdrom/gdrom.c   | 46 +++++++++++++-------
 src/guest/gdrom/gdrom.h   |  7 ++-
 src/guest/gdrom/patch.c   | 83 ++++++++++++++++++++++++++++++++++++
 src/guest/gdrom/patch.h   | 30 +++++++++++++
 src/guest/gdrom/patch.inc | 22 ++++++++++
 src/guest/pvr/pvr.c       |  2 +-
 src/guest/pvr/ta.c        |  2 +-
 17 files changed, 297 insertions(+), 145 deletions(-)
 create mode 100644 src/guest/gdrom/patch.c
 create mode 100644 src/guest/gdrom/patch.h
 create mode 100644 src/guest/gdrom/patch.inc

diff --git a/CMakeLists.txt b/CMakeLists.txt
index ff63e155..47fe04e2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -197,6 +197,7 @@ set(RELIB_SOURCES
   src/guest/gdrom/disc.c
   src/guest/gdrom/gdi.c
   src/guest/gdrom/gdrom.c
+  src/guest/gdrom/patch.c
   src/guest/holly/holly.c
   src/guest/maple/controller.c
   src/guest/maple/maple.c
diff --git a/src/emulator.c b/src/emulator.c
index 42896c12..f46215a5 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -38,7 +38,6 @@
 DEFINE_AGGREGATE_COUNTER(frames);
 
 DEFINE_PERSISTENT_OPTION_STRING(aspect_ratio, "stretch", "Video aspect ratio");
-DEFINE_PERSISTENT_OPTION_INT(widescreen_hack, 1, "Enable widescreen hacks");
 
 static const char *aspect_ratios[] = {
     "stretch", "4:3",
@@ -554,13 +553,6 @@ static void emu_debug_menu(struct emu *emu) {
           }
         }
 
-        igSeparator();
-
-        if (igMenuItem("widescreen hack", NULL, OPTION_widescreen_hack, 1)) {
-          OPTION_widescreen_hack = !OPTION_widescreen_hack;
-          LOG_WARNING("widescreen hack settings changed, restart to apply");
-        }
-
         igEndMenu();
       }
       igEndMenu();
@@ -570,6 +562,7 @@ static void emu_debug_menu(struct emu *emu) {
   }
 
   bios_debug_menu(emu->dc->bios);
+  gdrom_debug_menu(emu->dc->gdrom);
   holly_debug_menu(emu->dc->holly);
   aica_debug_menu(emu->dc->aica);
   sh4_debug_menu(emu->dc->sh4);
diff --git a/src/guest/aica/aica.c b/src/guest/aica/aica.c
index a8b35d09..47262c7f 100644
--- a/src/guest/aica/aica.c
+++ b/src/guest/aica/aica.c
@@ -799,7 +799,7 @@ static void aica_toggle_recording(struct aica *aica) {
 static int aica_init(struct device *dev) {
   struct aica *aica = (struct aica *)dev;
 
-  aica->wave_ram = memory_translate(aica->memory, "aica wave ram", 0x00000000);
+  aica->wave_ram = memory_translate(aica->memory, "aica wave ram", 0x0);
 
   /* init channels */
   {
diff --git a/src/guest/arm7/arm7.c b/src/guest/arm7/arm7.c
index 3e202ede..5a4c06ad 100644
--- a/src/guest/arm7/arm7.c
+++ b/src/guest/arm7/arm7.c
@@ -213,7 +213,7 @@ static int arm7_init(struct device *dev) {
   arm->jit = jit_create("arm7", arm->frontend, arm->backend,
                         (struct jit_guest *)arm->guest);
 
-  arm->wave_ram = memory_translate(dc->memory, "aica wave ram", 0x00000000);
+  arm->wave_ram = memory_translate(dc->memory, "aica wave ram", 0x0);
 
   return 1;
 }
diff --git a/src/guest/bios/bios.c b/src/guest/bios/bios.c
index a2b74039..c2917bf8 100644
--- a/src/guest/bios/bios.c
+++ b/src/guest/bios/bios.c
@@ -217,7 +217,7 @@ static int bios_boot(struct bios *bios) {
 
   LOG_INFO("bios_boot using hle bootstrap");
 
-  /* load ip.bin bootstrap */
+  /* load IP.BIN bootstrap */
   {
     /* bootstrap occupies the first 16 sectors of the data track */
     struct gd_spi_session data_session;
@@ -234,31 +234,22 @@ static int bios_boot(struct bios *bios) {
     as_memcpy_to_guest(space, BOOT1_ADDR, tmp, read);
   }
 
-  /* load 1st_read.bin into ram */
+  /* load 1ST_READ.BIN into ram */
   {
-    const char *bootfile = "1ST_READ.BIN";
-
-    int fad;
-    int len;
-    int found = gdrom_find_file(gd, bootfile, &fad, &len);
-    if (!found) {
-      LOG_WARNING("bios_boot failed to find %s", bootfile);
-      return 0;
-    }
+    int fad, len;
+    gdrom_get_bootfile(gd, &fad, &len);
 
     /* copy the bootfile into ram */
     uint8_t *tmp = malloc(len);
     int read = gdrom_read_bytes(gd, fad, len, tmp, len);
     if (read != len) {
-      LOG_WARNING("bios_boot failed to copied %s", bootfile);
+      LOG_WARNING("bios_boot failed to copy bootfile");
       free(tmp);
       return 0;
     }
 
     as_memcpy_to_guest(space, BOOT2_ADDR, tmp, read);
     free(tmp);
-
-    LOG_INFO("bios_boot found '%s' at fad=%d size=%d", bootfile, fad, len);
   }
 
   /* write system info */
diff --git a/src/guest/dreamcast.c b/src/guest/dreamcast.c
index 9d0fcf65..97deb76d 100644
--- a/src/guest/dreamcast.c
+++ b/src/guest/dreamcast.c
@@ -140,6 +140,7 @@ int dc_init(struct dreamcast *dc) {
     }
   }
 
+  /* initialize after devices in order to manipulate the boot and flash roms */
   if (!bios_init(dc->bios)) {
     LOG_WARNING("failed to initialize bios");
     return 0;
diff --git a/src/guest/gdrom/cdi.c b/src/guest/gdrom/cdi.c
index 05ae0123..b82f1176 100644
--- a/src/guest/gdrom/cdi.c
+++ b/src/guest/gdrom/cdi.c
@@ -34,54 +34,24 @@ struct cdi {
   int num_tracks;
 };
 
-static int cdi_read_sectors(struct disc *disc, int fad, int num_sectors,
-                            int sector_fmt, int sector_mask, void *dst,
-                            int dst_size) {
+static void cdi_read_sector(struct disc *disc, struct track *track, int fad,
+                            void *dst) {
   struct cdi *cdi = (struct cdi *)disc;
 
-  struct track *track = disc_lookup_track(disc, fad);
-  CHECK_NOTNULL(track);
-  CHECK(sector_fmt == GD_SECTOR_ANY || sector_fmt == track->sector_fmt);
-  CHECK(sector_mask == GD_MASK_DATA);
-
   /* seek the to the starting fad */
   int offset = track->file_offset + fad * track->sector_size;
   int res = fseek(cdi->fp, offset, SEEK_SET);
   CHECK_EQ(res, 0);
 
   /* only read the data portion of the track */
-  int header_size, error_size, data_size;
+  res = fseek(cdi->fp, track->header_size, SEEK_CUR);
+  CHECK_EQ(res, 0);
 
-  if (track->sector_fmt == GD_SECTOR_CDDA) {
-    header_size = 0;
-    error_size = 0;
-    data_size = track->sector_size - header_size - error_size;
-    CHECK_EQ(data_size, 2352);
-  } else if (track->sector_fmt == GD_SECTOR_M2F1) {
-    header_size = 8;
-    error_size = 280;
-    data_size = track->sector_size - header_size - error_size;
-    CHECK_EQ(data_size, 2048);
-  } else {
-    CHECK(0);
-  }
+  res = (int)fread(dst, 1, track->data_size, cdi->fp);
+  CHECK_EQ(res, track->data_size);
 
-  int read = 0;
-
-  for (int i = 0; i < num_sectors; i++) {
-    res = fseek(cdi->fp, header_size, SEEK_CUR);
-    CHECK_EQ(res, 0);
-
-    CHECK_LE(read + data_size, dst_size);
-    res = (int)fread(dst + read, 1, data_size, cdi->fp);
-    CHECK_EQ(res, data_size);
-    read += res;
-
-    res = fseek(cdi->fp, error_size, SEEK_CUR);
-    CHECK_EQ(res, 0);
-  }
-
-  return read;
+  res = fseek(cdi->fp, track->error_size, SEEK_CUR);
+  CHECK_EQ(res, 0);
 }
 
 static void cdi_get_toc(struct disc *disc, int area, struct track **first_track,
@@ -224,8 +194,25 @@ static int cdi_parse_track(struct disc *disc, uint32_t version,
   track->fad = pregap_length + lba;
   track->adr = 0;
   track->ctrl = sector_fmt == GD_SECTOR_CDDA ? 0 : 4;
+
   track->sector_fmt = cdi_sector_formats[mode];
   track->sector_size = sector_size;
+  if (track->sector_fmt == GD_SECTOR_CDDA) {
+    track->header_size = 0;
+    track->error_size = 0;
+    track->data_size =
+        track->sector_size - track->header_size - track->error_size;
+    CHECK_EQ(track->data_size, 2352);
+  } else if (track->sector_fmt == GD_SECTOR_M2F1) {
+    track->header_size = 8;
+    track->error_size = 280;
+    track->data_size =
+        track->sector_size - track->header_size - track->error_size;
+    CHECK_EQ(track->data_size, 2048);
+  } else {
+    LOG_FATAL("unexpected sector format %d", track->sector_fmt);
+  }
+
   track->file_offset = data_offset - track->fad * track->sector_size;
 
   LOG_INFO("cdi_parse_track track=%d fad=%d off=%d mode=%s/%d", track->num,
@@ -379,7 +366,7 @@ struct disc *cdi_create(const char *filename) {
   cdi->get_num_tracks = &cdi_get_num_tracks;
   cdi->get_track = &cdi_get_track;
   cdi->get_toc = &cdi_get_toc;
-  cdi->read_sectors = &cdi_read_sectors;
+  cdi->read_sector = &cdi_read_sector;
 
   struct disc *disc = (struct disc *)cdi;
 
diff --git a/src/guest/gdrom/disc.c b/src/guest/gdrom/disc.c
index 5b6391c1..fc93ffea 100644
--- a/src/guest/gdrom/disc.c
+++ b/src/guest/gdrom/disc.c
@@ -4,6 +4,7 @@
 #include "guest/gdrom/cdi.h"
 #include "guest/gdrom/gdi.h"
 #include "guest/gdrom/iso.h"
+#include "guest/gdrom/patch.h"
 
 /* meta information found in the ip.bin */
 struct disc_meta {
@@ -38,8 +39,8 @@ int disc_read_bytes(struct disc *disc, int fad, int len, void *dst,
   int rem = len;
 
   while (rem) {
-    int n = disc->read_sectors(disc, fad, 1, GD_SECTOR_ANY, GD_MASK_DATA, tmp,
-                               sizeof(tmp));
+    int n = disc_read_sectors(disc, fad, 1, GD_SECTOR_ANY, GD_MASK_DATA, tmp,
+                              sizeof(tmp));
     CHECK(n);
 
     /* don't overrun */
@@ -57,8 +58,29 @@ int disc_read_bytes(struct disc *disc, int fad, int len, void *dst,
 int disc_read_sectors(struct disc *disc, int fad, int num_sectors,
                       int sector_fmt, int sector_mask, void *dst,
                       int dst_size) {
-  return disc->read_sectors(disc, fad, num_sectors, sector_fmt, sector_mask,
-                            dst, dst_size);
+  struct track *track = disc_lookup_track(disc, fad);
+  CHECK_NOTNULL(track);
+  CHECK(sector_fmt == GD_SECTOR_ANY || sector_fmt == track->sector_fmt);
+  CHECK(sector_mask == GD_MASK_DATA);
+
+  int read = 0;
+  int endfad = fad + num_sectors;
+  int bootstart = disc->bootfad;
+  int bootend = disc->bootfad + (disc->bootlen / track->data_size);
+
+  for (int i = fad; i < endfad; i++) {
+    CHECK_LE(read + track->data_size, dst_size);
+    disc->read_sector(disc, track, i, dst + read);
+    read += track->data_size;
+  }
+
+  /* apply bootfile patches */
+  if (bootstart <= endfad && fad <= bootend) {
+    int offset = (fad - bootstart) * track->data_size;
+    patch_bootfile(disc->id, dst, offset, read);
+  }
+
+  return read;
 }
 
 int disc_find_file(struct disc *disc, const char *filename, int *fad,
@@ -67,10 +89,10 @@ int disc_find_file(struct disc *disc, const char *filename, int *fad,
 
   /* get the session for the main data track */
   struct session *session = disc_get_session(disc, 1);
-  struct track *data_track = disc_get_track(disc, session->first_track);
+  struct track *track = disc_get_track(disc, session->first_track);
 
   /* read primary volume descriptor */
-  int read = disc_read_sectors(disc, data_track->fad + ISO_PVD_SECTOR, 1,
+  int read = disc_read_sectors(disc, track->fad + ISO_PVD_SECTOR, 1,
                                GD_SECTOR_ANY, GD_MASK_DATA, tmp, sizeof(tmp));
   if (!read) {
     return 0;
@@ -164,31 +186,12 @@ int disc_get_num_sessions(struct disc *disc) {
   return disc->get_num_sessions(disc);
 }
 
-void disc_destroy(struct disc *disc) {
-  disc->destroy(disc);
-}
-
 int disc_get_format(struct disc *disc) {
   return disc->get_format(disc);
 }
 
-void disc_get_id(struct disc *disc, char *id, int size) {
-  struct disc_meta meta;
-  disc_get_meta(disc, &meta);
-
-  char device_info[17];
-  char product_number[11];
-  char product_version[7];
-  char name[129];
-  strncpy_trim_spaces(device_info, meta.device_info, sizeof(meta.device_info));
-  strncpy_trim_spaces(product_number, meta.product_number,
-                      sizeof(meta.product_number));
-  strncpy_trim_spaces(product_version, meta.product_version,
-                      sizeof(meta.product_version));
-  strncpy_trim_spaces(name, meta.name, sizeof(meta.name));
-
-  snprintf(id, size, "%s %s %s %s", name, product_number, product_version,
-           device_info);
+void disc_destroy(struct disc *disc) {
+  disc->destroy(disc);
 }
 
 struct disc *disc_create(const char *filename) {
@@ -200,11 +203,36 @@ struct disc *disc_create(const char *filename) {
     disc = gdi_create(filename);
   }
 
-  if (disc) {
-    char id[DISC_MAX_ID_SIZE];
-    disc_get_id(disc, id, sizeof(id));
-    LOG_INFO("disc_create %s", id);
+  if (!disc) {
+    return NULL;
   }
 
+  /* generate a unique id for the disc, and cache off info about the bootfile */
+  struct disc_meta meta;
+  disc_get_meta(disc, &meta);
+
+  char device_info[17];
+  char product_number[11];
+  char product_version[7];
+  char bootname[17];
+  char name[129];
+
+  strncpy_trim_spaces(device_info, meta.device_info, sizeof(meta.device_info));
+  strncpy_trim_spaces(product_number, meta.product_number,
+                      sizeof(meta.product_number));
+  strncpy_trim_spaces(product_version, meta.product_version,
+                      sizeof(meta.product_version));
+  strncpy_trim_spaces(bootname, meta.bootname, sizeof(meta.bootname));
+  strncpy_trim_spaces(name, meta.name, sizeof(meta.name));
+
+  snprintf(disc->id, sizeof(disc->id), "%s %s %s %s", name, product_number,
+           product_version, device_info);
+
+  int found = disc_find_file(disc, bootname, &disc->bootfad, &disc->bootlen);
+  CHECK(found);
+
+  LOG_INFO("disc_create %s bootfad=%d bootlen=%d", disc->id, disc->bootfad,
+           disc->bootlen);
+
   return disc;
 }
diff --git a/src/guest/gdrom/disc.h b/src/guest/gdrom/disc.h
index c48d083e..d21184b2 100644
--- a/src/guest/gdrom/disc.h
+++ b/src/guest/gdrom/disc.h
@@ -11,11 +11,19 @@
 
 struct track {
   int num;
+  /* frame adddress, equal to lba + 150 */
   int fad;
+  /* type of information encoded in the sub q channel */
   int adr;
+  /* type of track */
   int ctrl;
+  /* sector info */
   int sector_fmt;
   int sector_size;
+  int header_size;
+  int error_size;
+  int data_size;
+  /* backing file */
   char filename[PATH_MAX];
   int file_offset;
 };
@@ -28,6 +36,10 @@ struct session {
 };
 
 struct disc {
+  char id[DISC_MAX_ID_SIZE];
+  int bootfad;
+  int bootlen;
+
   void (*destroy)(struct disc *);
 
   int (*get_format)(struct disc *);
@@ -40,22 +52,22 @@ struct disc {
 
   void (*get_toc)(struct disc *, int, struct track **, struct track **, int *,
                   int *);
-  int (*read_sectors)(struct disc *, int, int, int, int, void *, int);
+  void (*read_sector)(struct disc *, struct track *, int, void *);
 };
 
 struct disc *disc_create(const char *filename);
 void disc_destroy(struct disc *disc);
 
-void disc_get_id(struct disc *disc, char *id, int size);
 int disc_get_format(struct disc *disc);
 int disc_get_num_sessions(struct disc *disc);
 struct session *disc_get_session(struct disc *disc, int n);
 int disc_get_num_tracks(struct disc *disc);
 struct track *disc_get_track(struct disc *disc, int n);
 struct track *disc_lookup_track(struct disc *disc, int fad);
-int disc_find_file(struct disc *disc, const char *filename, int *fad, int *len);
 void disc_get_toc(struct disc *disc, int area, struct track **first_track,
                   struct track **last_track, int *leadin_fad, int *leadout_fad);
+
+int disc_find_file(struct disc *disc, const char *filename, int *fad, int *len);
 int disc_read_sectors(struct disc *disc, int fad, int num_sectors,
                       int sector_fmt, int sector_mask, void *dst, int dst_size);
 int disc_read_bytes(struct disc *disc, int fad, int len, void *dst,
diff --git a/src/guest/gdrom/gdi.c b/src/guest/gdrom/gdi.c
index fae6c551..179eead2 100644
--- a/src/guest/gdrom/gdi.c
+++ b/src/guest/gdrom/gdi.c
@@ -11,16 +11,10 @@ struct gdi {
   int num_tracks;
 };
 
-static int gdi_read_sectors(struct disc *disc, int fad, int num_sectors,
-                            int sector_fmt, int sector_mask, void *dst,
-                            int dst_size) {
+static void gdi_read_sector(struct disc *disc, struct track *track, int fad,
+                            void *dst) {
   struct gdi *gdi = (struct gdi *)disc;
 
-  struct track *track = disc_lookup_track(disc, fad);
-  CHECK_NOTNULL(track);
-  CHECK(sector_fmt == GD_SECTOR_ANY || sector_fmt == track->sector_fmt);
-  CHECK(sector_mask == GD_MASK_DATA);
-
   /* open the file backing the track */
   int n = (int)(track - gdi->tracks);
   FILE *fp = gdi->files[n];
@@ -36,27 +30,14 @@ static int gdi_read_sectors(struct disc *disc, int fad, int num_sectors,
   CHECK_EQ(res, 0);
 
   /* only read the data portion of the track */
-  int header_size = 16;
-  int error_size = 288;
-  int data_size = track->sector_size - header_size - error_size;
-  CHECK_EQ(data_size, 2048);
+  res = fseek(fp, track->header_size, SEEK_CUR);
+  CHECK_EQ(res, 0);
 
-  int read = 0;
+  res = (int)fread(dst, 1, track->data_size, fp);
+  CHECK_EQ(res, track->data_size);
 
-  for (int i = 0; i < num_sectors; i++) {
-    res = fseek(fp, header_size, SEEK_CUR);
-    CHECK_EQ(res, 0);
-
-    CHECK_LE(read + data_size, dst_size);
-    res = (int)fread(dst + read, 1, data_size, fp);
-    CHECK_EQ(res, data_size);
-    read += res;
-
-    res = fseek(fp, error_size, SEEK_CUR);
-    CHECK_EQ(res, 0);
-  }
-
-  return read;
+  res = fseek(fp, track->error_size, SEEK_CUR);
+  CHECK_EQ(res, 0);
 }
 
 static void gdi_get_toc(struct disc *disc, int area, struct track **first_track,
@@ -167,8 +148,14 @@ static int gdi_parse(struct disc *disc, const char *filename) {
     track->num = gdi->num_tracks;
     track->fad = lba + GDROM_PREGAP;
     track->ctrl = ctrl;
+
     track->sector_fmt = GD_SECTOR_M1;
     track->sector_size = sector_size;
+    track->header_size = 16;
+    track->error_size = 288;
+    track->data_size =
+        track->sector_size - track->header_size - track->error_size;
+
     track->file_offset = file_offset - track->fad * track->sector_size;
     snprintf(track->filename, sizeof(track->filename), "%s" PATH_SEPARATOR "%s",
              dirname, filename);
@@ -215,7 +202,7 @@ struct disc *gdi_create(const char *filename) {
   gdi->get_num_tracks = &gdi_get_num_tracks;
   gdi->get_track = &gdi_get_track;
   gdi->get_toc = &gdi_get_toc;
-  gdi->read_sectors = &gdi_read_sectors;
+  gdi->read_sector = &gdi_read_sector;
 
   struct disc *disc = (struct disc *)gdi;
 
diff --git a/src/guest/gdrom/gdrom.c b/src/guest/gdrom/gdrom.c
index 763870ac..56606093 100644
--- a/src/guest/gdrom/gdrom.c
+++ b/src/guest/gdrom/gdrom.c
@@ -4,7 +4,9 @@
 #include "guest/dreamcast.h"
 #include "guest/gdrom/gdrom_replies.inc"
 #include "guest/gdrom/gdrom_types.h"
+#include "guest/gdrom/patch.h"
 #include "guest/holly/holly.h"
+#include "render/imgui.h"
 
 #if 0
 #define LOG_GDROM LOG_INFO
@@ -490,16 +492,6 @@ int gdrom_read_sectors(struct gdrom *gd, int fad, int num_sectors, int fmt,
                            dst_size);
 }
 
-int gdrom_find_file(struct gdrom *gd, const char *filename, int *fad,
-                    int *len) {
-  if (!gd->disc) {
-    LOG_WARNING("gdrom_find_file failed, no disc");
-    return 0;
-  }
-
-  return disc_find_file(gd->disc, filename, fad, len);
-}
-
 void gdrom_get_subcode(struct gdrom *gd, int format, uint8_t *data, int size) {
   CHECK_NOTNULL(gd->disc);
   CHECK_GE(size, GD_SPI_SCD_SIZE);
@@ -640,12 +632,6 @@ void gdrom_get_drive_mode(struct gdrom *gd, struct gd_hw_info *info) {
   *info = gd->hw_info;
 }
 
-void gdrom_get_disc_id(struct gdrom *gd, char *id, int size) {
-  CHECK_NOTNULL(gd->disc);
-
-  disc_get_id(gd->disc, id, size);
-}
-
 void gdrom_dma_end(struct gdrom *gd) {
   LOG_GDROM("gd_dma_end");
 }
@@ -680,6 +666,20 @@ void gdrom_dma_begin(struct gdrom *gd) {
   LOG_GDROM("gd_dma_begin");
 }
 
+int gdrom_find_file(struct gdrom *gd, const char *filename, int *fad,
+                    int *len) {
+  CHECK_NOTNULL(gd->disc);
+
+  return disc_find_file(gd->disc, filename, fad, len);
+}
+
+void gdrom_get_bootfile(struct gdrom *gd, int *fad, int *len) {
+  CHECK_NOTNULL(gd->disc);
+
+  *fad = gd->disc->bootfad;
+  *len = gd->disc->bootlen;
+}
+
 void gdrom_set_disc(struct gdrom *gd, struct disc *disc) {
   if (gd->disc != disc) {
     if (gd->disc) {
@@ -707,6 +707,20 @@ void gdrom_set_disc(struct gdrom *gd, struct disc *disc) {
   /* TODO how do GD_FEATURES, GD_INTREASON, GD_BYCTLLO and GD_BYCTLHI behave */
 }
 
+#ifdef HAVE_IMGUI
+void gdrom_debug_menu(struct gdrom *gd) {
+  if (igBeginMainMenuBar()) {
+    if (igBeginMenu("GDROM", 1)) {
+      patch_debug_menu();
+
+      igEndMenu();
+    }
+
+    igEndMainMenuBar();
+  }
+}
+#endif
+
 void gdrom_destroy(struct gdrom *gd) {
   if (gd->disc) {
     disc_destroy(gd->disc);
diff --git a/src/guest/gdrom/gdrom.h b/src/guest/gdrom/gdrom.h
index 1e084e31..3d7e4a7d 100644
--- a/src/guest/gdrom/gdrom.h
+++ b/src/guest/gdrom/gdrom.h
@@ -10,12 +10,16 @@ struct gdrom;
 struct gdrom *gdrom_create(struct dreamcast *dc);
 void gdrom_destroy(struct gdrom *gd);
 
+void gdrom_debug_menu(struct gdrom *gd);
+
 void gdrom_set_disc(struct gdrom *gd, struct disc *disc);
+void gdrom_get_bootfile(struct gdrom *gd, int *fad, int *len);
+int gdrom_find_file(struct gdrom *gd, const char *filename, int *fad, int *len);
+
 void gdrom_dma_begin(struct gdrom *gd);
 int gdrom_dma_read(struct gdrom *gd, uint8_t *data, int n);
 void gdrom_dma_end(struct gdrom *gd);
 
-void gdrom_get_disc_id(struct gdrom *gd, char *id, int size);
 void gdrom_get_drive_mode(struct gdrom *gd, struct gd_hw_info *info);
 void gdrom_set_drive_mode(struct gdrom *gd, struct gd_hw_info *info);
 void gdrom_get_status(struct gdrom *gd, struct gd_spi_status *stat);
@@ -24,7 +28,6 @@ void gdrom_get_toc(struct gdrom *gd, int area, struct gd_spi_toc *toc);
 void gdrom_get_session(struct gdrom *gd, int session,
                        struct gd_spi_session *ses);
 void gdrom_get_subcode(struct gdrom *gd, int format, uint8_t *data, int size);
-int gdrom_find_file(struct gdrom *gd, const char *filename, int *fad, int *len);
 int gdrom_read_sectors(struct gdrom *gd, int fad, int num_sectors, int fmt,
                        int mask, uint8_t *dst, int dst_size);
 int gdrom_read_bytes(struct gdrom *gd, int fad, int len, uint8_t *dst,
diff --git a/src/guest/gdrom/patch.c b/src/guest/gdrom/patch.c
new file mode 100644
index 00000000..ad25e88b
--- /dev/null
+++ b/src/guest/gdrom/patch.c
@@ -0,0 +1,83 @@
+#include "guest/gdrom/patch.h"
+#include "core/assert.h"
+#include "core/string.h"
+#include "guest/memory.h"
+#include "render/imgui.h"
+
+DEFINE_PERSISTENT_OPTION_INT(patch_widescreen, 1, "Apply widescreen patches");
+
+#if 0
+#define LOG_PATCH LOG_INFO
+#else
+#define LOG_PATCH(...)
+#endif
+
+#define DATA(...) \
+  (uint8_t[]) {   \
+    __VA_ARGS__   \
+  }
+
+#define HUNKS(...)        \
+  (struct patch_hunk[]) { \
+    __VA_ARGS__           \
+  }
+
+#define NUM_HUNKS(...) (sizeof(HUNKS(__VA_ARGS__)) / sizeof(struct patch_hunk))
+
+#define HUNK(offset, ...) \
+  { offset, DATA(__VA_ARGS__), sizeof(DATA(__VA_ARGS__)) }
+
+#define PATCH(game, desc, flags, ...) \
+  {game, desc, flags, HUNKS(__VA_ARGS__), NUM_HUNKS(__VA_ARGS__)},
+
+static struct patch patches[] = {
+#include "guest/gdrom/patch.inc"
+};
+static int num_patches = sizeof(patches) / sizeof(patches[0]);
+
+void patch_bootfile(const char *game, uint8_t *buffer, int offset, int size) {
+  for (int i = 0; i < num_patches; i++) {
+    struct patch *patch = &patches[i];
+
+    /* only apply patches for the current game */
+    if (strcmp(patch->game, game)) {
+      continue;
+    }
+
+    if (!(patch->flags & PATCH_BOOTFILE)) {
+      continue;
+    }
+
+    if ((patch->flags & PATCH_WIDESCREEN) && !OPTION_patch_widescreen) {
+      continue;
+    }
+
+    LOG_PATCH("patches_apply %s at 0x%x", patch->desc, offset);
+
+    for (int j = 0; j < patch->num_hunks; j++) {
+      struct patch_hunk *hunk = &patch->hunks[j];
+
+      for (int k = 0; k < hunk->len; k++) {
+        int index = hunk->offset + k;
+
+        if (index < offset || index >= offset + size) {
+          continue;
+        }
+
+        buffer[index - offset] = hunk->data[k];
+      }
+    }
+  }
+}
+
+#ifdef HAVE_IMGUI
+void patch_debug_menu() {
+  if (igBeginMenu("patches", 1)) {
+    if (igMenuItem("widescreen", NULL, OPTION_patch_widescreen, 1)) {
+      OPTION_patch_widescreen = !OPTION_patch_widescreen;
+    }
+
+    igEndMenu();
+  }
+}
+#endif
diff --git a/src/guest/gdrom/patch.h b/src/guest/gdrom/patch.h
new file mode 100644
index 00000000..bee29be7
--- /dev/null
+++ b/src/guest/gdrom/patch.h
@@ -0,0 +1,30 @@
+#ifndef PATCH_H
+#define PATCH_H
+
+#include <stdint.h>
+
+struct address_space;
+
+enum {
+  PATCH_BOOTFILE = 0x1,
+  PATCH_WIDESCREEN = 0x2,
+};
+
+struct patch_hunk {
+  int offset;
+  uint8_t *data;
+  int len;
+};
+
+struct patch {
+  char *game;
+  char *desc;
+  int flags;
+  struct patch_hunk *hunks;
+  int num_hunks;
+};
+
+void patch_debug_menu();
+void patch_bootfile(const char *game, uint8_t *data, int offset, int size);
+
+#endif
diff --git a/src/guest/gdrom/patch.inc b/src/guest/gdrom/patch.inc
new file mode 100644
index 00000000..9aa21c60
--- /dev/null
+++ b/src/guest/gdrom/patch.inc
@@ -0,0 +1,22 @@
+PATCH("DYNAMITE COP MK-51013 V1.005 7996 GD-ROM1/1",
+  "widescreen hack",
+  PATCH_BOOTFILE | PATCH_WIDESCREEN,
+  HUNK(0x00048eb0,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x00048fb8,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x00049100,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0004b590,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0006b93c,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0006bce0,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0006c0d0,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0006c21c,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0006eec4,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x000723c0,0x39,0x8E,0xE3,0x3F),
+  HUNK(0x0007d568,0x39,0x8E,0xE3,0x3F))
+
+PATCH("SONIC ADVENTURE MK-51000 V1.005 3B97 GD-ROM1/1",
+  "widescreen hack",
+  PATCH_BOOTFILE | PATCH_WIDESCREEN,
+  HUNK(0x00026fb8,0xF0,0xF5,0x88,0x8C,0xF4,0xF5,0x88,0x8C,0x94,0x3A,0x01,0x8C),
+  HUNK(0x00026fc4,0x80,0xEF,0x0A,0x8C,0x10,0xF6,0x88,0x8C,0x18,0xF6,0x88,0x8C),
+  HUNK(0x00600d70,0x80,0xEF,0x0A,0x8C,0xA8,0x35,0x67,0x8C,0xE6,0x2F,0x43,0x6E),
+  HUNK(0x00612200,0x80,0xEF,0x0A,0x8C,0x18,0x03,0x89,0x8C,0x59,0xF0,0x59,0xF1))
diff --git a/src/guest/pvr/pvr.c b/src/guest/pvr/pvr.c
index b5f77e45..2a831e05 100644
--- a/src/guest/pvr/pvr.c
+++ b/src/guest/pvr/pvr.c
@@ -233,7 +233,7 @@ static int pvr_init(struct device *dev) {
 #undef PVR_REG
 
   pvr->palette_ram = (uint8_t *)pvr->PALETTE_RAM000;
-  pvr->video_ram = memory_translate(dc->memory, "video ram", 0x00000000);
+  pvr->video_ram = memory_translate(dc->memory, "video ram", 0x0);
 
   /* configure initial vsync interval */
   pvr_reconfigure_spg(pvr);
diff --git a/src/guest/pvr/ta.c b/src/guest/pvr/ta.c
index 7d1cad32..e6a397ff 100644
--- a/src/guest/pvr/ta.c
+++ b/src/guest/pvr/ta.c
@@ -625,7 +625,7 @@ static int ta_init(struct device *dev) {
   struct ta *ta = (struct ta *)dev;
   struct dreamcast *dc = ta->dc;
 
-  ta->video_ram = memory_translate(dc->memory, "video ram", 0x00000000);
+  ta->video_ram = memory_translate(dc->memory, "video ram", 0x0);
 
   for (int i = 0; i < array_size(ta->contexts); i++) {
     struct tile_context *ctx = &ta->contexts[i];