X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=boot%2Fboot.asm;fp=boot%2Fboot.asm;h=2b74db8265dd34740ed1795d4ada85145d570aeb;hb=be7535b3af9d7ecc5581a7b3d325f5caec87b24f;hp=5b82c2d37d43d858d6e37cffd2dd3779aa8a1f36;hpb=06692d6c927aae4e6f06efd1e401d005839c1e5f;p=eightysix

diff --git a/boot/boot.asm b/boot/boot.asm
index 5b82c2d..2b74db8 100644
--- a/boot/boot.asm
+++ b/boot/boot.asm
@@ -3,10 +3,9 @@
 	bits 16
 	section .bootsect
 
-extern _stage2_start
-extern _stage2_end
+extern _stage2_start_seg
+extern _stage2_size
 
-stacktop	equ 7b00h
 boot_driveno	equ 7b00h
 num_read_tries	equ 7b06h	; 2 bytes
 sect_pending	equ 7b08h	; 2 bytes
@@ -58,12 +57,12 @@ start:
 	xor ax, ax
 	mov ds, ax
 	mov es, ax
-	mov ss, ax
-	mov gs, ax
-	mov fs, ax
 	jmp 00:.setcs
 .setcs:
-	mov sp, stacktop
+	; put the stack high
+	mov ax, 0x7f00
+	mov ss, ax
+	xor sp, sp
 	mov [boot_driveno], dl
 
 	; query sectors per track
@@ -84,20 +83,15 @@ start:
 	mov word [num_heads], 2
 .querydone:
 
-; load the rest of the code at 7e00h
-	mov ax, _stage2_end
-	sub ax, _stage2_start
+	; load the rest of the code high
+	mov ax, _stage2_size
 	add ax, 511
 	mov cl, 9
 	shr ax, cl
 	inc ax
 	mov [sect_pending], ax
-	mov ax, _stage2_start
-	shr ax, 1
-	shr ax, 1
-	shr ax, 1
-	shr ax, 1
-	mov es, ax	; destination segment 7e0h to allow loading up to 64k
+	mov ax, _stage2_start_seg
+	mov es, ax	; destination segment
 	mov word [destptr], 0
 	mov word [start_sect], 1	; start from sector 1 to skip boot sector
 	mov word [cur_cyl], 0
@@ -170,10 +164,15 @@ start:
 	add [destptr], ax
 	jnz .rdloop
 
-	; loaded sucessfully, reset es back to 0 and jump
-.done:	xor ax, ax
+	; loaded sucessfully, load segment registers and jump
+.done:	mov ax, _stage2_start_seg
+	mov ds, ax
 	mov es, ax
-	jmp _stage2_start
+	push ax
+	xor ax, ax
+	push ax
+	retf
+
 
 .fail:	add sp, 2	; clear num_sect off the stack
 	dec word [num_read_tries]