diff --git a/hw/dma.c b/hw/dma.c
index c2d7b21..e7de522 100644
--- a/hw/dma.c
+++ b/hw/dma.c
@@ -56,6 +56,7 @@ static struct dma_cont {
     uint8_t mask;
     uint8_t flip_flop;
     int dshift;
+    int iobase;
     struct dma_regs regs[4];
     qemu_irq *cpu_request_exit;
     MemoryRegion channel_io;
@@ -192,7 +193,8 @@ static void write_chan(void *opaque, hwaddr nport, uint64_t data,
     }
 }
 
-static void write_cont(void *opaque, hwaddr nport, uint64_t data,
+
+static void __write_cont(void *opaque, hwaddr nport, uint64_t data,
                        unsigned size)
 {
     struct dma_cont *d = opaque;
@@ -200,7 +202,7 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
 
     iport = (nport >> d->dshift) & 0x0f;
     switch (iport) {
-    case 0x01:                  /* command */
+    case 0x08:                  /* command */
         if ((data != 0) && (data & CMD_NOT_SUPPORTED)) {
             dolog("command %"PRIx64" not supported\n", data);
             return;
@@ -208,7 +210,7 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
         d->command = data;
         break;
 
-    case 0x02:
+    case 0x09:
         ichan = data & 3;
         if (data & 4) {
             d->status |= 1 << (ichan + 4);
@@ -220,7 +222,7 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
         DMA_run();
         break;
 
-    case 0x03:                  /* single mask */
+    case 0x0a:                  /* single mask */
         if (data & 4)
             d->mask |= 1 << (data & 3);
         else
@@ -228,7 +230,7 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
         DMA_run();
         break;
 
-    case 0x04:                  /* mode */
+    case 0x0b:                  /* mode */
         {
             ichan = data & 3;
 #ifdef DEBUG_DMA
@@ -247,23 +249,23 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
             break;
         }
 
-    case 0x05:                  /* clear flip flop */
+    case 0x0c:                  /* clear flip flop */
         d->flip_flop = 0;
         break;
 
-    case 0x06:                  /* reset */
+    case 0x0d:                  /* reset */
         d->flip_flop = 0;
         d->mask = ~0;
         d->status = 0;
         d->command = 0;
         break;
 
-    case 0x07:                  /* clear mask for all channels */
+    case 0x0e:                  /* clear mask for all channels */
         d->mask = 0;
         DMA_run();
         break;
 
-    case 0x08:                  /* write mask for all channels */
+    case 0x0f:                  /* write mask for all channels */
         d->mask = data;
         DMA_run();
         break;
@@ -281,11 +283,22 @@ static void write_cont(void *opaque, hwaddr nport, uint64_t data,
 #endif
 }
 
+static void write_cont(void *opaque, hwaddr nport, uint64_t data,
+                       unsigned size)
+{
+    struct dma_cont *d = opaque;
+    int add = d->iobase + (8 << d->dshift);
+
+    __write_cont(opaque, nport+add, data, size);
+}
+
 static uint64_t read_cont(void *opaque, hwaddr nport, unsigned size)
 {
     struct dma_cont *d = opaque;
     int iport, val;
 
+    nport += d->iobase + (8 << d->dshift);
+
     iport = (nport >> d->dshift) & 0x0f;
     switch (iport) {
     case 0x08:                  /* status */
@@ -467,7 +480,7 @@ void DMA_schedule(int nchan)
 static void dma_reset(void *opaque)
 {
     struct dma_cont *d = opaque;
-    write_cont(d, (0x06 << d->dshift), 0, 1);
+    __write_cont(d, (0xd << d->dshift), 0, 1);
 }
 
 static int dma_phony_handler (void *opaque, int nchan, int dma_pos, int dma_len)
@@ -523,7 +536,7 @@ static void dma_init2(struct dma_cont *d, int base, int dshift,
     d->cpu_request_exit = cpu_request_exit;
 
     memory_region_init_io(&d->channel_io, &channel_io_ops, d,
-                          "dma-chan", 8 << d->dshift);
+                          "dma-chan", 8);
     memory_region_add_subregion(isa_address_space_io(NULL),
                                 base, &d->channel_io);
 
@@ -535,12 +548,13 @@ static void dma_init2(struct dma_cont *d, int base, int dshift,
     }
 
     memory_region_init_io(&d->cont_io, &cont_io_ops, d, "dma-cont",
-                          8 << d->dshift);
+                          8);
     memory_region_add_subregion(isa_address_space_io(NULL),
                                 base + (8 << d->dshift), &d->cont_io);
 
     qemu_register_reset(dma_reset, d);
     dma_reset(d);
+    d->iobase = base;
     for (i = 0; i < ARRAY_SIZE (d->regs); ++i) {
         d->regs[i].transfer_handler = dma_phony_handler;
     }
