Allocate cdemu buffer in low mem instead of ebda.

Using the low memory buffer gives more flexibility with the final
location of the buffer.

Don't allocate the buffer at all if no cdrom drives are present.

diff --git a/src/biosvar.h b/src/biosvar.h
index ea2d67d9a499004fdcd8e585c16531cd0573b1b0..dce35af24aecfb6eeb1da9ef1f464fa5a9450162 100644 (file)
--- a/src/biosvar.h
+++ b/src/biosvar.h
@@ -234,8 +234,6 @@ struct extended_bios_data_area_s {
 
     // Stack space available for code that needs it.
     u8 extra_stack[512] __aligned(8);
-
-    u8 cdemu_buf[2048 * !!CONFIG_CDROM_EMU];
 } PACKED;
 
 // The initial size and location of EBDA

diff --git a/src/cdrom.c b/src/cdrom.c
index f7af425f823cd0ae8845c2e37f85503e0cd5d838..655ee00ad09ffebc8f045f225c01b9182570b78c 100644 (file)
--- a/src/cdrom.c
+++ b/src/cdrom.c
@@ -17,6 +17,9 @@
  * CD emulation
  ****************************************************************/
 
+struct drive_s *cdemu_drive_gf VAR16VISIBLE;
+u8 *cdemu_buf_fl VAR16VISIBLE;
+
 static int
 cdemu_read(struct disk_op_s *op)
 {
@@ -30,12 +33,12 @@ cdemu_read(struct disk_op_s *op)
 
     int count = op->count;
     op->count = 0;
-    u8 *cdbuf_far = (void*)offsetof(struct extended_bios_data_area_s, cdemu_buf);
+    u8 *cdbuf_fl = GET_GLOBAL(cdemu_buf_fl);
 
     if (op->lba & 3) {
         // Partial read of first block.
         dop.count = 1;
-        dop.buf_fl = MAKE_FLATPTR(ebda_seg, cdbuf_far);
+        dop.buf_fl = cdbuf_fl;
         int ret = process_op(&dop);
         if (ret)
             return ret;
@@ -43,10 +46,7 @@ cdemu_read(struct disk_op_s *op)
         if (thiscount > count)
             thiscount = count;
         count -= thiscount;
-        memcpy_far(FLATPTR_TO_SEG(op->buf_fl)
-                   , (void*)FLATPTR_TO_OFFSET(op->buf_fl)
-                   , ebda_seg, cdbuf_far + (op->lba & 3) * 512
-                   , thiscount * 512);
+        memcpy_fl(op->buf_fl, cdbuf_fl + (op->lba & 3) * 512, thiscount * 512);
         op->buf_fl += thiscount * 512;
         op->count += thiscount;
         dop.lba++;
@@ -69,14 +69,12 @@ cdemu_read(struct disk_op_s *op)
     if (count) {
         // Partial read on last block.
         dop.count = 1;
-        dop.buf_fl = MAKE_FLATPTR(ebda_seg, cdbuf_far);
+        dop.buf_fl = cdbuf_fl;
         int ret = process_op(&dop);
         if (ret)
             return ret;
         u8 thiscount = count;
-        memcpy_far(FLATPTR_TO_SEG(op->buf_fl)
-                   , (void*)FLATPTR_TO_OFFSET(op->buf_fl)
-                   , ebda_seg, cdbuf_far, thiscount * 512);
+        memcpy_fl(op->buf_fl, cdbuf_fl, thiscount * 512);
         op->count += thiscount;
     }
 
@@ -106,22 +104,27 @@ process_cdemu_op(struct disk_op_s *op)
     }
 }
 
-struct drive_s *cdemu_drive_gf VAR16VISIBLE;
-
 void
 cdemu_setup(void)
 {
     if (!CONFIG_CDROM_EMU)
         return;
+    cdemu_drive_gf = NULL;
+    cdemu_buf_fl = NULL;
+    if (!Drives.cdcount)
+        return;
 
     struct drive_s *drive_g = malloc_fseg(sizeof(*drive_g));
-    if (! drive_g) {
+    u8 *buf = malloc_low(CDROM_SECTOR_SIZE);
+    if (!drive_g || !buf) {
         warn_noalloc();
-        cdemu_drive_gf = NULL;
+        free(drive_g);
+        free(buf);
         return;
     }
-    memset(drive_g, 0, sizeof(*drive_g));
     cdemu_drive_gf = drive_g;
+    cdemu_buf_fl = buf;
+    memset(drive_g, 0, sizeof(*drive_g));
     drive_g->type = DTYPE_CDEMU;
     drive_g->blksize = DISK_SECTOR_SIZE;
     drive_g->sectors = (u64)-1;

diff --git a/src/post.c b/src/post.c
index 25535e21f2949c046e2217104bdc4420f406e167..fc7acc585c1814a231e0a672d2957d44441980d2 100644 (file)
--- a/src/post.c
+++ b/src/post.c
@@ -217,7 +217,6 @@ post(void)
     // Initialize internal tables
     boot_setup();
     drive_setup();
-    cdemu_setup();
 
     // Start hardware initialization (if optionrom threading)
     if (CONFIG_THREADS && CONFIG_THREAD_OPTIONROMS)
@@ -250,6 +249,7 @@ post(void)
     boot_prep();
 
     // Finalize data structures before boot
+    cdemu_setup();
     pmm_finalize();
     malloc_finalize();
     memmap_finalize();