Initial revision

1 files changed, 88 insertions, 0 deletions

diff --git a/src/drivers/disk/floppy.c b/src/drivers/disk/floppy.c
new file mode 100644
index 000000000..9cb0a22da
--- /dev/null
+++ b/src/drivers/disk/floppy.c
@@ -0,0 +1,88 @@
+#if	(TRY_FLOPPY_FIRST > 0)
+
+/*
+ * 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; either version 2, or (at
+ * your option) any later version.
+ */
+
+#include "etherboot.h"
+
+#define BOOTSECT ((char *)0x7C00)
+#define BOOTSIG  ((unsigned short *)BOOTSECT)[0xFF]
+#define PARTTAB  ((partentry *)(BOOTSECT+0x1BE))
+
+typedef struct partentry {
+	unsigned char flags;
+	unsigned char start_head;
+	unsigned char start_sector;
+	unsigned char start_cylinder;
+	unsigned char type;
+	unsigned char end_head;
+	unsigned char end_sector;
+	unsigned char end_cylinder;
+	unsigned long offset;
+	unsigned long length;
+} partentry;
+
+static unsigned int disk_read_retry(int dev,int c,int h,int s)
+{
+	int retry = 3,rc;
+
+	while (retry-- && (rc = pcbios_disk_read(dev,c,h,s,BOOTSECT)) != 0);
+	if (BOOTSIG != 0xAA55) {
+		printf("not a boot sector");
+		return(0xFFFF); }
+	return(rc);
+}
+
+int bootdisk(int dev,int part)
+{
+	int rc;
+
+	disk_init();
+	if ((rc = disk_read_retry(dev,0,0,1)) != 0) {
+	readerr:
+		if (rc != 0xFFFF)
+			printf("read error (%#hhX)",rc/256);
+		return(0); }
+	if (part) {
+		partentry *ptr;
+
+		if (part >= 5) {
+			int i;
+			for (i = 0, ptr = PARTTAB; ptr->type != 5; ptr++)
+				if (++i == 4) {
+					printf("partition not found");
+					return(0); }
+			if ((rc = disk_read_retry(dev,
+						  ptr->start_cylinder,
+						  ptr->start_head,
+						  ptr->start_sector)) != 0)
+				goto readerr;
+			part -= 4; }
+		if (!(ptr = PARTTAB-1+part)->type) {
+			printf("empty partition");
+			return(0); }
+		if ((rc = disk_read_retry(dev,
+					  ptr->start_cylinder,
+					  ptr->start_head,
+					  ptr->start_sector)) != 0)
+			goto readerr; }
+	cleanup();
+	gateA20_unset();
+	/* Set %edx to device number to emulate BIOS
+	   Fortunately %edx is not used after this */
+	__asm__("movl %0,%%edx" : : "g" (dev));
+	xstart((unsigned long)BOOTSECT, 0, 0);
+	return(0);
+}
+
+#endif
+
+/*
+ * Local variables:
+ *  c-basic-offset: 8
+ * End:
+ */