Initial source

1 files changed, 75 insertions, 0 deletions

diff --git a/i386/dos/dos_read.c b/i386/dos/dos_read.c
new file mode 100644
index 00000000..ae7213fb
--- /dev/null
+++ b/i386/dos/dos_read.c
@@ -0,0 +1,75 @@
+/* 
+ * Copyright (c) 1995-1994 The University of Utah and
+ * the Computer Systems Laboratory at the University of Utah (CSL).
+ * All rights reserved.
+ *
+ * Permission to use, copy, modify and distribute this software is hereby
+ * granted provided that (1) source code retains these copyright, permission,
+ * and disclaimer notices, and (2) redistributions including binaries
+ * reproduce the notices in supporting documentation, and (3) all advertising
+ * materials mentioning features or use of this software display the following
+ * acknowledgement: ``This product includes software developed by the
+ * Computer Systems Laboratory at the University of Utah.''
+ *
+ * THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
+ * IS" CONDITION.  THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
+ * ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * CSL requests users of this software to return to csl-dist@cs.utah.edu any
+ * improvements that they make and grant CSL redistribution rights.
+ *
+ *      Author: Bryan Ford, University of Utah CSL
+ */
+
+#include <unistd.h>
+#include <errno.h>
+
+#include "dos_io.h"
+#include "vm_param.h"
+
+int dos_read(dos_fd_t fd, void *buf, vm_size_t size, vm_size_t *out_actual)
+{
+	int err;
+	int actual = 0;
+	struct real_call_data real_call_data;
+	vm_offset_t dos_buf_phys = (vm_offset_t)kvtophys(dos_buf);
+
+	assert(dos_buf); assert(dos_buf_phys);
+	assert(dos_buf_phys < 0x100000);
+
+	dos_init_rcd(&real_call_data);
+
+	while (size > 0)
+	{
+		int little_size = size;
+		int little_actual;
+
+		if (little_size > DOS_BUF_SIZE)
+			little_size = DOS_BUF_SIZE;
+
+		real_call_data.eax = 0x3f00;
+		real_call_data.ebx = fd;
+		real_call_data.ecx = little_size;
+		real_call_data.ds = dos_buf_phys >> 4;
+		real_call_data.edx = dos_buf_phys & 15;
+		real_int(0x21, &real_call_data);
+		if (err = dos_check_err(&real_call_data))
+			return err;
+		little_actual = real_call_data.eax & 0xffff;
+		assert(little_actual <= little_size);
+
+		/* XXX don't copy if buf is <1MB */
+		memcpy(buf, dos_buf, little_actual);
+
+		buf += little_actual;
+		size -= little_actual;
+		actual += little_actual;
+
+		if (little_actual < little_size)
+			break;
+	}
+
+	*out_actual = actual;
+	return 0;
+}
+