hdprefix that works for LBA only

src/arch/i386/prefix/bootpart.S

@@ -44,7 +44,7 @@ find_active_partition:
 	jc	1f
 	cmpw	$0xaa55, %bx
 	jne	1f
-	movw	$read_lba, read_sector
+	movw	$read_lba, read_sectors
 1:	
 	/* Read and process root partition table */
 	xorb	%dh, %dh
@@ -55,17 +55,26 @@ find_active_partition:
 
 	/* Print failure message */
 	movw	$10f, %si
-	movw	$(20f-10f), %cx
-1:	movw	$0x0007, %bx
+	jmp	boot_error
+10:	.asciz	"Could not locate active partition\r\n"
+
+/*
+ * Print failure message and boot next device
+ *
+ * Parameters:
+ *   %si	: Failure string
+ */
+boot_error:
+	cld
+	movw	$0x0007, %bx
 	movb	$0x0e, %ah
-	lodsb
+1:	lodsb
+	testb	%al, %al
+	je	99f
 	int	$0x10
-	loop	1b
-
-	/* Boot next device */
+	jmp	1b
+99:	/* Boot next device */
 	int	$0x18
-10:	.ascii	"Could not locate active partition\r\n"
-20:	
 
 /*
  * Process partition table
@@ -149,7 +158,7 @@ process_partition:
 read_boot_sector:
 	pushw	%ax
 	movw	$1, %ax
-	call	*read_sector
+	call	*read_sectors
 	jc	99f
 	cmpw	$0xaa55, %es:(510)
 	je	99f
@@ -158,7 +167,7 @@ read_boot_sector:
 	ret
 	
 /*
- * Read single sector to %es:0000 and verify 0x55aa signature
+ * Read sectors to %es:0000
  *
  * Parameters:
  *   %dl	: BIOS drive number
@@ -171,7 +180,7 @@ read_boot_sector:
  * Returns:
  *   CF set on error
  */
-read_sector:	.word	read_chs
+read_sectors:	.word	read_chs
 
 read_chs:
 	/* Read sectors using C/H/S address */

src/arch/i386/prefix/hdprefix.S

@@ -1,301 +1,63 @@
-#warning "Needs fixing up for gpxe"
-
-#if 0
-
-/****************************************************************\
-
-hdprefix.S Copyright (C) 2005 Per Dalgas Jakobsen
-
-This code has been inspired/derived by the OSLoader by Vladislav Aleksandrov.
-http://www.programmersheaven.com/zone5/cat469/40546.htm.
-
-This software may be used and distributed according to the terms
-of the GNU Public License (GPL), incorporated herein by reference.
-
-hdprefix.S is loaded at 0x0000:0x7c00 by the bios-startup routines.
-
-Actions performed by hdprefix:
-1) Load the MBR to LOADSEG:0
-2) Check which partition is active (or try first partition if none active)
-3) Check wether LBA is supported.
-3a) LBA
-3a1) Load PAYLOAD_SECTS sectors from chosen partition to LOADSEG:0
-3b) CHS (standard)
-3b1) Load PAYLOAD_SECTS sectors from chosen partition to LOADSEG:0
-4) Check loaded bootsector for BOOTMAGIC code.
-5) Jump to payload LOADSEG:ENTRYPOINT.
-
-Output with failure points (!#):
----
-Loading (!1)partition #
-Std. BIOS(!2) | Ext. BIOS(!3)
-Booting...(!4)
-(!5)
----
-
-!1: Failed to load MBR with Int13,ah=2.
-!2: Failed to load bootrecord+payload with Int13,ah=2.
-!3: Failed to load bootrecord+payload with Int13,ah=42.
-!4: Invalid BOOTMAGIC in loaded bootrecord.
-!5: Jumping to payload.
-
-\*****************************************************************/
- 
-.equ	BOOTSEG,	0x07c0
-.equ	LOADSEG,	0x1000
-.equ	ENTRYPOINT,	_start
-
-.equ	BOOTMAGIC,	0x0aa55
-
-.equ	partition_table,	0x1be
-.equ	partition_rec_size,	0x10
-
-.equ	boot_ind,	0	/* 80h=active */
-.equ	start_head,	1
-.equ	start_sector,	2	/* bits 0-5 */
-.equ	start_cyl,	3	/* bits 8,9 in bits 6,7 of sector */
-.equ	os_ind,		4	/* os indicator */
-.equ	end_head,	5
-.equ	end_sector,	6	/* bits 0-5 */
-.equ	end_track,	7	/* bits 8,9 in bits 6,7 of sector */
-.equ	nsect,		8	/* sectors preceding partition */
-.equ	lenght,		0x0c	/* length of partition in sectors */
-
-/-------------------------------------------------------------
-
-	.arch i386
 	.text
-	.section ".prefix", "ax", @progbits
+	.arch i386
+	.section ".prefix", "awx", @progbits
 	.code16
-	 
-bootstart:
-	jmp	$BOOTSEG,$_go		/* reload cs:ip */
-
-
-/****************************************************************/
-/* support routines.						*/
-/*--------------------------------------------------------------*/
-_failed:
-	movw	$BOOTSEG,%ax
-	movw	%ax,%ds
-	movw	$_failed_msg_end-_failed_msg,%cx
-	movw	$_failed_msg,%si
-	call	_print_str
-
-	/* stop execution - should probably have option to auto-reboot after delay. */
-_failed_loop:
-	jmp	_failed_loop
-
-/*--------------------------------------------------------------*/
-_print_str:
-	/* cx = count, ds:si = string. */
-	movw	$0x0007,%bx
-	movb	$0x0e,%ah
-_print_loop:
-	lodsb
-	int	$0x10
-	loop	_print_loop
-	ret
-
-/*--------------------------------------------------------------*/			
-_print_char:
-	/* al = char. */
-	movw	$0x0007,%bx
-	movb	$0x0e,%ah
-	int	$0x10
-	ret
-
-/*--------------------------------------------------------------*/
-_print_nl:
-	/* - */
-	movb	$0x0d,%al
-	call	_print_char
-	movb	$0x0a,%al
-	call	_print_char
-	ret
-
-/*--------------------------------------------------------------*/
-_print_hex:
-	/* dx = value */
-	movb	$0x0e,%ah	/* write char, tty mode */
-	movw	$0x0007,%bx	/* page 0, attribute 7 (normal) */
-	call	_print_digit
-	call	_print_digit
-	call	_print_digit
-	/* fall through */
-_print_digit:
-	rolw	$4,%dx		/* rotate so that lowest 4 bits are used */
-	movb	$0x0f,%al	/* mask for nibble */
-	andb	%dl,%al
-	addb	$0x90,%al	/* convert al to ascii hex (four instructions) */
-	daa
-	adcb	$0x40,%al
-	daa
-	int	$0x10
-	ret
-
-/****************************************************************/
-
-
-_go:
-	cli
-	movw	$BOOTSEG,%ax
-	movw	%ax,%ds
-	movw	%ax,%ss
-	movw	$0x2000,%sp	/* good large stack. */
-	sti
-	cld
-	movw	$LOADSEG,%ax
-	movw	%ax,%es
-
-	movw	$_load_msg_end-_load_msg,%cx
-	movw	$_load_msg,%si
-	call	_print_str
-
-/*--- load MBR so we can use its partition table. ---*/
-	xorw	%bx,%bx
-	movw	$0x0001,%cx	/* chs: 0,0,1 */
-	movb	%bh,%dh		/* - */
-	movb	$0x80,%dl
-	movw	$0x0201,%ax	/* read one sector (MBR) */
-	int	$0x13
-	jc	_failed
-
-/*--- find the active partition ---*/
-	movw	$_part_msg_end-_part_msg,%cx
-	movw	$_part_msg,%si
-	call	_print_str
-
-	movw	$partition_table,%di
-	movw	$4,%cx
-_partition_loop:
-	cmpb	$0x80,%es:(%di)		/* active? */
-	je	_partition_found
-	addw	$partition_rec_size,%di
-	loop	_partition_loop
-
-	/*- no partitions marked active - use 1. partition. */
-	movw	$partition_table,%di
-	movw	$4,%cx
-
-_partition_found:
-	movb	$'5',%al			/* convert to ascii */
-	subb	%cl,%al
-	call	_print_char
-	call	_print_nl
-
-/*--- check for lba support ---*/
-	movw	$0x55aa,%bx
-	movb	$0x80,%dl
-	movb	$0x41,%ah
-	int	$0x13
-	jc	__bios
-	cmpw	$0x0aa55,%bx
-	jnz	__bios
-	testb	$1,%cl
-	jz	__bios
-
-/*--- use lba bios calls to read sectors ---*/
-_lba:
-	movw	$_extbios_msg_end-_extbios_msg,%cx
-	movw	$_extbios_msg,%si
-	call	_print_str
-
-	movw	%es:nsect(%di),%ax
-	movw	%ax,_bios_lba_low
-	movw	%es:nsect+2(%di),%ax
-	movw	%ax,_bios_lba_high
-	movb	$0x80,%dl
-	movw	$_disk_address_packet,%si
-	movw	$0x4200,%ax	/* read */
-	int	$0x13
-	jc	_failed
-	jmp	__loaded
-
-/*--- use standard bios calls to read sectors ---*/
-__bios:
-	movw	$_stdbios_msg_end-_stdbios_msg,%cx
-	movw	$_stdbios_msg,%si
-	call	_print_str
-
-	movw	_disk_address_packet+2(,1),%ax	/* only low byte is used. */
-	xorw	%bx,%bx
-	movw	%es:start_sector(%di),%cx
-	movb	%es:start_head(%di),%dh
-	movb	$0x80,%dl
-	movb	$0x02,%ah
-	int	$0x13
-	jc	_failed
-
-__loaded:
-	movw	$_boot_msg_end-_boot_msg,%cx
-	movw	$_boot_msg,%si
-	call	_print_str
-
-	/* check if it has a valid bootrecord. */
-	cmpw	$BOOTMAGIC,%es:510(,1)
-	jne	_failed
-	call	_print_nl
-
-	/* call the payload. */
-	pushl	$0		/* No parameters to preserve for exit path */
-	pushw	$0		/* Use prefix exit path mechanism */
-	jmp	$LOADSEG,$ENTRYPOINT
-
-	.section ".text16", "ax", @progbits
-	.globl	prefix_exit
-prefix_exit:
-	int	$0x19		/* should try to boot machine */
-	.globl	prefix_exit_end
-prefix_exit_end:
-	.previous
-	 
-
-/*--------------------------------------------------------------*/
-
-_load_msg:	.ascii	"Loading "
-_load_msg_end:
-_part_msg:	.ascii	"partition "
-_part_msg_end:
-_boot_msg:	.ascii	"Booting..."
-_boot_msg_end:
-_stdbios_msg:	.ascii	"Std. BIOS\r\n"
-_stdbios_msg_end:
-_extbios_msg:	.ascii	"Ext. BIOS\r\n"
-_extbios_msg_end:
-_failed_msg:	.ascii	"FAILED!!!\r\n"
-_failed_msg_end:
-
-
-/*--------------------------------------------------------------*/
-
-_disk_address_packet:
-		.byte	0x10		/* size of the packet */
-		.byte	0		/* reserved */
-		.word	_verbatim_size_sct	/* number of sectors to read */
-		.word	0x0000		/* offset */
-		.word	LOADSEG 	/* segment of buffer */
-_bios_lba_low:	.word	0
-_bios_lba_high:	.word	0
-		.word	0
-		.word	0
-
-	.rept 32
-		.byte	0
-	.endr
-
-
-/*--- Partition table ------------------------------------------*/
-
-	.org 446, 0
-	.rept 64
-		.byte	0
-	.endr
-
-
-/*--- Magic code -----------------------------------------------*/
-	.org 510, 0
-		.word BOOTMAGIC
-
-/*** END ********************************************************/
-#endif
+	.org 0
+
+	movw	$load_image, %bp
+	jmp	find_active_partition
+
+#include "bootpart.S"
+
+load_image:
+	movw	$_rom_size, %bp
+1:	/* Truncate read length to end of track */
+	movzwl	%bp, %eax
+			movw	$1, %ax
+	/* Read sectors */
+	call	*read_sectors
+	jc	load_failed
+	/* Update %es */
+	movw	%es, %bx
+	shll	$5, %eax
+	addw	%ax, %bx
+	movw	%bx, %es
+	shrl	$5, %eax
+	/* Update LBA address */
+	addl	%eax, %edi
+	adcl	$0, %esi
+	/* Update CHS address */
+			// hmmmm
+	/* Loop until whole image is read */
+	subw	%ax, %bp
+	jne	1b
+	ljmp	$BOOT_SEG, $start_image
+
+load_failed:
+	movw	$10f, %si
+	jmp	boot_error
+10:	.asciz	"Could not load gPXE\r\n"
+
+	.org 510
+	.byte 0x55, 0xaa
+
+start_image:
+	call	install
+
+	/* Set up real-mode stack */
+	movw	%bx, %ss
+	movw	$_estack16, %sp
+
+	/* Jump to .text16 segment */
+	pushw	%ax
+	pushw	$1f
+	lret
+	.section ".text16", "awx", @progbits
+1:
+	pushl	$main
+	pushw	%cs
+	call	prot_call
+	popl	%eax /* discard */
+
+	/* Boot next device */
+	int $0x18