From e6805ee94cc57c552cc0a4d000106da74fcfc72a Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Mon, 4 Aug 2003 22:00:00 -0400
Subject: [PATCH] Import backup from 2003-08-04

---
 bootsect.asm | 150 +++++++++++++++++++++++++--------------------------
 1 file changed, 72 insertions(+), 78 deletions(-)

diff --git a/bootsect.asm b/bootsect.asm
index a79ce0a..2cb6333 100644
--- a/bootsect.asm
+++ b/bootsect.asm
@@ -134,76 +134,69 @@ error:
 	jmp	$			;halt! no kernel file found!
 
 found_file:				;ds:si points to root dir entry of kernel file
-	mov	di, 160				;;;;;;;
-
 	mov	ax, KERNEL_SEG
 	mov	es, ax
-	mov	ax, [ds:si+26]		;first logical cluster
+
+	mov	ax, [ds:si+26]
 	mov	bx, FAT_SEG
-	mov	ds, bx
+	mov	ds, bx			;ds points to beginning of FAT
 	xor	bx, bx
-loop_readkernel:
-	cmp	ax, 0xFF7
-	jg	donereadkernel
-	push	ax			;<> save cluster#
-	push	bx			;<> save index
+
+readkernel_loop:
+	cmp	ax, 0xff7
+	jg	readkernel_done
+	;inc	word	[k_count]
+	push	ax
+	push	bx
 	call	getCHSfromCluster
+	pop	bx
+	push	bx
 	mov	ax, 0x0201
 	mov	dl, [brDrive]
 	int	0x13
 	pop	bx
 	add	bx, 512
-	pop	ax			;<> restore cluster#
-	cmp	bx, 0			;if bx=0 then it wrapped, 64k loaded, increment es by 64k
-	jne	loop_readkernel_goon
+	cmp	bx, 0
+	jne	readkernel_goon
 	mov	bx, es
-	add	bx, 0x1000
+	add	bx, 0x0100
 	mov	es, bx
 	xor	bx, bx
-loop_readkernel_goon:
-	mov	cx, ax			;save backup of cluster#
+readkernel_goon:
+	pop	ax			;current logical cluster #
+
+	mov	cx, ax			;cx=logical cluster
 	mov	dx, 3
-	mul	dx			;ax=logical cluster*3
-	shr	ax, 1			;ax=logical cluster*3/2
-	mov	si, ax			;ds:si points to first byte of word containing FAT entry
-	test	cl, 1			;is cluster# odd?
+	mul	dx
+	shr	ax, 1			;ax=logical cluster * 3 / 2
+	mov	si, ax
+	test	cl, 1			;is bit0 set?
 	jnz	odd_cluster
 even_cluster:
-	mov	cl, [ds:si+1]
-	and	cl, 0x0f
-	shl	cx, 8
-	mov	cl, [ds:si]
+	lodsw
+	and	ax, 0x0fff
 	jmp	got_cluster
 odd_cluster:
-	xor	cx, cx
-	mov	cl, [ds:si+1]
-	shl	cx, 4
-	xor	dx, dx
-	mov	dl, [ds:si]
-	shr	dl, 4
-	add	cx, dx
+	lodsw
+	shr	ax, 4
 got_cluster:
-	push	es				;;;;;;;
-	mov	ax, 0xb800
-	mov	es, ax
-	mov	al, ch
-	call	puthex
-	mov	al, cl
-	call	puthex
-	inc	di
-	inc	di				;;;;;;;
+	jmp	readkernel_loop
 
-	mov	ax, cx
-	jmp	loop_readkernel
+readkernel_done:			;now copy kernel to final location in KERNEL_ADD!
 
-donereadkernel:				;done reading kernel!
-	mov	ax, 0xb800
-	mov	es, ax
-	xor	di, di
-	mov	al, bh
-	call	puthex
-	mov	al, bl
-	call	puthex
+;	mov	ax, KERNEL_SEG
+;	mov	ds, ax
+;	xor	esi, esi
+;	xor	ax, ax
+;	mov	es, ax
+;	mov	edi, KERNEL_ADD
+;	xor	ecx, ecx
+;	mov	cx, [k_count]		;cx=# of 512byte sectors loaded
+;	shl	ecx, 9			;ecx=ecx*512
+;movekernel_loop:
+;	o32 lodsb			;mov	al, [ds:esi]
+;	o32 stosb			;mov	[es:edi], al
+;	o32 loop	movekernel_loop
 
 	jmp	$
 
@@ -224,35 +217,35 @@ getCHSfromCluster:
 	ret
 
 ;------------------------------------------------------
-puthex:
-	;es:di points to video memory
-	;al holds hex value
-
-	push	ax
-	mov	ah, al
-	shr	ax, 4
-	and	al, 0x0F
-	add	al, '0'
-	cmp	al, '9'
-	jle	puthex_goon1
-	add	al, 'A'-'9'-1
-puthex_goon1:
-	stosb
-	mov	al, 7
-	stosb
-	pop	ax
-	push	ax
-	and	al, 0x0F
-	add	al, '0'
-	cmp	al, '9'
-	jle	puthex_goon2
-	add	al, 'A'-'9'-1
-puthex_goon2:
-	stosb
-	mov	al, 7
-	stosb
-	pop	ax
-	ret
+;puthex:
+;	;es:di points to video memory
+;	;al holds hex value
+;
+;	push	ax
+;	mov	ah, al
+;	shr	ax, 4
+;	and	al, 0x0F
+;	add	al, '0'
+;	cmp	al, '9'
+;	jle	puthex_goon1
+;	add	al, 'A'-'9'-1
+;puthex_goon1:
+;	stosb
+;	mov	al, 7
+;	stosb
+;	pop	ax
+;	push	ax
+;	and	al, 0x0F
+;	add	al, '0'
+;	cmp	al, '9'
+;	jle	puthex_goon2
+;	add	al, 'A'-'9'-1
+;puthex_goon2:
+;	stosb
+;	mov	al, 7
+;	stosb
+;	pop	ax
+;	ret
 
 ;-------------------------------------------------------
 gdtr:
@@ -274,6 +267,7 @@ gdt:
 gdt_end:
 
 kernel:	db	"KERNEL  BIN"
+k_count: dw	0
 
 times 510-($-$$)	db 0