Revert "Added master boot record capable of locating active partition"

This reverts commit 844d088c51.

src/arch/i386/prefix/bootpart.S

@@ -1,190 +0,0 @@
-#define BOOT_SEG	0x07c0
-#define EXEC_SEG	0x0100
-#define STACK_SEG 	0x0200
-#define STACK_SIZE	0x2000
-	
-	.text
-	.arch i386
-	.section ".prefix", "awx", @progbits
-	.code16
-
-/*
- * Find active partition
- *
- * Parameters:
- *   %dl	: BIOS drive number
- *   %bp	: Active partition handler routine
- */
-find_active_partition:
-	/* Set up stack at STACK_SEG:STACK_SIZE */
-	movw	$STACK_SEG, %ax
-	movw	%ax, %ss
-	movw	$STACK_SIZE, %sp
-	/* Relocate self to EXEC_SEG */
-	pushw	$BOOT_SEG
-	popw	%ds
-	pushw	$EXEC_SEG
-	popw	%es
-	xorw	%si, %si
-	xorw	%di, %di
-	movw	$0x200, %cx
-	rep movsb
-	ljmp	$EXEC_SEG, $1f
-1:	pushw	%ds
-	popw	%es
-	pushw	%cs
-	popw	%ds
-	/* Read and process root partition table */
-	xorb	%dh, %dh
-	movw	$0x0001, %cx
-	xorl	%esi, %esi
-	xorl	%edi, %edi
-	call	process_table
-	/* Print failure message */
-	movw	$10f, %si
-	movw	$(20f-10f), %cx
-1:	movw	$0x0007, %bx
-	movb	$0x0e, %ah
-	lodsb
-	int	$0x10
-	loop	1b
-	/* Boot next device */
-	int	$0x18
-10:	.ascii	"Could not locate active partition\r\n"
-20:	
-
-/*
- * Process partition table
- *
- * Parameters:
- *   %dl	: BIOS drive number
- *   %dh	: Head
- *   %cl	: Sector (bits 0-5), high two bits of cylinder (bits 6-7)
- *   %ch	: Low eight bits of cylinder
- *   %esi:%edi	: LBA address
- *   %bp	: Active partition handler routine
- *
- * Returns:
- *   CF set on error
- */
-process_table:
-				xchgw	%bx,%bx
-	pushal
-	movw	$446, %bx
-1:	call	read_sector
-	jc	99f
-	call	process_partition
-	addw	$16, %bx
-	cmpw	$510, %bx
-	jne	1b
-99:	popal
-	ret
-
-/*
- * Process partition
- *
- * Parameters:
- *   %dl	: BIOS drive number
- *   %dh	: Head
- *   %cl	: Sector (bits 0-5), high two bits of cylinder (bits 6-7)
- *   %ch	: Low eight bits of cylinder
- *   %esi:%edi	: LBA address
- *   %bx	: Offset within partition table
- *   %bp	: Active partition handler routine
- */
-process_partition:
-	pushal
-	/* Load C/H/S values from partition entry */
-	movb	%es:1(%bx), %dh
-	movw	%es:2(%bx), %cx
-	/* Update LBA address from partition entry */
-	addl	%es:8(%bx), %edi
-	adcl	$0, %esi
-	/* Check active flag */
-	testb	$0x80, %es:(%bx)
-	jz	1f
-	call	read_sector
-	jc	99f
-	jmp	*%bp
-1:	/* Check for extended partition */
-	movb	%es:4(%bx), %al
-	cmpb	$0x05, %al
-	je	2f
-	cmpb	$0x0f, %al
-	je	2f
-	cmpb	$0x85, %al
-	jne	99f
-2:	call	process_table
-99:	popal
-	ret
-
-/*
- * Read single sector to 0000:7c00 and verify 0x55aa signature
- *
- * Parameters:
- *   %dl	: BIOS drive number
- *   %dh	: Head
- *   %cl	: Sector (bits 0-5), high two bits of cylinder (bits 6-7)
- *   %ch	: Low eight bits of cylinder
- *   %esi:%edi	: LBA address
- *
- * Returns:
- *   CF set on error
- */
-read_sector:
-	pushal
-	/* Check for LBA extensions */
-	call	check_lba
-	jnc	read_lba
-read_chs:
-	/* Read sector using C/H/S address */
-	movw	$0x0201, %ax
-	xorw	%bx, %bx
-	stc
-	int	$0x13
-	sti
-	jmp	99f
-read_lba:
-	/* Read sector using LBA address */
-	movb	$0x42, %ah
-	movl	%esi, (lba_desc + 12)
-	movl	%edi, (lba_desc + 8)
-	movw	$lba_desc, %si
-	int	$0x13
-99:	/* Check for 55aa signature */
-	jc	99f
-	cmpw	$0xaa55, %es:(510)
-	je	99f
-	stc
-99:	popal
-	ret
-
-lba_desc:
-	.byte	0x10
-	.byte	0
-	.word	1
-	.word	0x0000
-	.word	0x07c0
-	.long	0, 0
-
-/*
- * Check for LBA extensions
- *	
- * Parameters:
- *   %dl	: BIOS drive number
- *
- * Returns:
- *   CF clear if LBA extensions supported
- */
-check_lba:
-	pushal
-	movb	$0x41, %ah
-	movw	$0x55aa, %bx
-	stc
-	int	$0x13
-	jc	99f
-	cmpw	$0xaa55, %bx
-	je	99f
-	stc
-99:	popal
-	ret

src/arch/i386/prefix/mbr.S

@@ -1,13 +0,0 @@
-	.text
-	.arch i386
-	.section ".prefix", "awx", @progbits
-	.code16
-	.org 0
-
-mbr:
-	movw	$exec_sector, %bp
-	jmp	find_active_partition
-exec_sector:
-	ljmp	$0x0000, $0x7c00
-
-#include "bootpart.S"