(2006-08-06) rescue-bootcd

extra/syslinux-3.09/sample/fd.c

@@ -0,0 +1,63 @@
+#ident "$Id: fd.c,v 1.2 2004/12/14 22:46:25 hpa Exp $"
+/* ----------------------------------------------------------------------- *
+ *   
+ *   Copyright 2003 H. Peter Anvin - All Rights Reserved
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * fd.c
+ *
+ * Chainload a floppy disk (currently rather braindead.)
+ */
+
+#include <com32.h>
+#define NULL ((void *)0)
+
+int printf(const char *, ...);
+unsigned int atou(const char *);
+
+int __start(void)
+{
+  int whichfd = atou(__com32.cs_cmdline);
+  static com32sys_t inreg, outreg; /* In bss, so zeroed automatically */
+  int retry;
+
+  for ( retry = 0 ; retry < 6 ; retry++ ) {
+    printf(">");
+    inreg.eax.w[0] = 0x0201;	/* Read one sector */
+    inreg.ecx.w[0] = 0x0001;	/* Cyl 0 sector 1 */
+    inreg.edx.b[1] = 0;		/* Head 0 */
+    inreg.edx.b[0] = whichfd;	/* Drive number */
+    inreg.es = SEG(__com32.cs_bounce); /* Read into the bounce buffer */
+    inreg.ebx.w[0] = OFFS(__com32.cs_bounce);
+    __com32.cs_intcall(0x13, &inreg, &outreg);
+
+    if ( (outreg.eflags.l & 1) == 0 )
+      break;
+  }
+
+  if ( (outreg.eflags.l & 1) == 0 ) {
+    printf("!\n");
+    inreg.eax.w[0] = 0x000d;
+    inreg.edx.w[0] = 0;
+    inreg.edi.l    = (uint32_t) __com32.cs_bounce;
+    inreg.ecx.l    = 512;
+    inreg.ebx.l    = whichfd & 0xff;
+    inreg.esi.l    = 0;		/* No partitions */
+    inreg.ds       = 0;		/* No partitions */
+    __com32.cs_intcall(0x22, &inreg, NULL);
+  }
+
+  /* If we get here, badness happened */
+  return 255;
+}
+
+
+