1 files changed, 77 insertions, 0 deletions
diff --git a/bootblocks/relocate.c b/bootblocks/relocate.c
new file mode 100644
index 0000000..121699e
--- /dev/null
+++ b/bootblocks/relocate.c
@@ -0,0 +1,77 @@
+
+#include <i86_funcs.h>
+
+static unsigned memseg = 0, memlen = 0;
+
+char buf[1];
+
+void
+relocator(newseg)
+unsigned newseg;
+{
+   unsigned moved, codelen;
+   unsigned es      = __get_es();
+
+   if( x86_test ) return;	/* I don't think so! */
+
+   /* Where do we start */
+   if(memseg == 0)
+   {
+      memseg = __get_cs();
+      codelen = __get_ds()-memseg;
+      __set_es(memseg-2);
+      memlen = __deek_es( 24 );
+      memlen >>=4;
+      if( memlen == 0 ) memlen = 0x1000;
+      memlen += codelen;
+      __set_es(es);
+   }
+
+   if( newseg < 0x50 ) return;
+
+   if( newseg == 0xFFFF )
+   {
+      newseg = boot_mem_top;
+      if( newseg > 0x90000 ) newseg = 0x90000;
+      newseg -= memlen;
+   }
+
+   /* If the old area overlaps the new then fail */
+   if( newseg >= memseg && newseg < memseg+memlen ) return;
+   if( memseg >= newseg && memseg < newseg+memlen ) return;
+
+   /* Copy segments, done in 32k chunks */
+   for(moved=0; moved < memlen; )
+   {
+       unsigned int lump;
+       if( memlen <= 0x800 ) lump = memlen; else lump = 0x800;
+
+       __movedata(memseg+moved, 0, newseg+moved, 0, (lump<<4));
+       moved += lump;
+   }
+
+   /* re-link int 0x80
+   __set_es(0);
+   __doke_es(0x80*4+2, newseg);
+   __set_es(es);
+   */
+
+   /* The actual jump ... */
+   memseg = newseg;
+#asm
+   mov	ax,ds
+   mov	bx,cs
+   sub	ax,bx
+   mov	bx,[_memseg]
+   add	ax,bx
+   push bx
+   call	L_x
+   mov	ds,ax
+   mov	ss,ax
+   mov	[_memseg],bx
+#endasm
+}
+#asm
+L_x:
+   retf
+#endasm