X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fboot%2Fboot2.s;h=37f102615d4c0ffe9a4c00b06c1b407427958366;hb=4c7af0d72e32cc07c04345bc9fe57a4a32a29695;hp=6372557ee2e3be08783404529b2713fbcfc354d5;hpb=559dd7c3c836a69eac46bd12c7ef61bb5de8882c;p=bootcensus

diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 6372557..37f1026 100644
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -37,8 +37,8 @@
 	# load the whole program into memory starting at 1MB
 	call load_main
 
-	mov $0x13, %ax
-	int $0x10
+	#mov $0x13, %ax
+	#int $0x10
 
 	# load initial GDT
 	lgdt (gdt_lim)
@@ -196,10 +196,11 @@ ldloop:
 	push %ecx
 	call read_track
 
-	mov buffer, %eax
-	call print_num
-	mov $10, %al
-	call putchar
+	# debug: print the first 32bits of the track
+	#mov buffer, %eax
+	#call print_num
+	#mov $10, %al
+	#call putchar
 
 	# copy to high memory
 	mov $buffer, %esi
@@ -348,14 +349,15 @@ abort_read:
 	jmp 0b
 
 
-
 	# better print routines, since we're not constrainted by the 512b of
 	# the boot sector.
+	.global cursor_x
+	.global cursor_y
 cursor_x: .long 0
 cursor_y: .long 0
 
 putchar:
-	pusha
+	pushal
 	call ser_putchar
 
 	cmp $10, %al
@@ -381,7 +383,7 @@ putchar:
 	jnz 1f
 	call video_newline
 
-1:	popa
+1:	popal
 	ret
 	
 	# expects string pointer in esi
@@ -397,7 +399,7 @@ putstr:
 	# expects number in eax
 print_num:
 	# save registers
-	pusha
+	pushal
 
 	mov $numbuf + 16, %esi
 	movb $0, (%esi)
@@ -414,7 +416,7 @@ convloop:
 	call putstr
 
 	# restore regs
-	popa
+	popal
 	ret
 
 
@@ -428,7 +430,7 @@ video_newline:
 0:	ret
 
 scrollup:
-	pusha
+	pushal
 	# move 80 * 24 lines from b80a0 -> b8000
 	mov $0xb8000, %edi
 	mov $0xb80a0, %esi
@@ -439,7 +441,7 @@ scrollup:
 	xor %eax, %eax
 	mov $40, %ecx
 	addr32 rep stosl
-	popa
+	popal
 	ret
 
 clearscr:
@@ -551,5 +553,76 @@ kbc_wait_write:
 
 numbuf: .space 16
 
+
+# this is not boot loader code. It's called later on by the main
+# kernel code in 32bit protected mode. It's placed here because
+# it needs to be in base memory as it returns and runs in real mode.
+
+	.code32
+	.align 4
+	# place to save the protected mode IDTR pseudo-descriptor
+	# with sidt, so that it can be restored before returning
+	.short 0
+saved_idtr:
+idtlim:	.short 0
+idtaddr:.long 0
+	# real mode IDTR pseudo-descriptor pointing to the IVT at addr 0
+	.short 0
+rmidt:	.short 0x3ff
+	.long 0
+
+	# drop back to unreal mode to set video mode
+	.global set_mode13h
+set_mode13h:
+	pushal
+	cli
+	# save protected mode IDTR and replace it with the real mode vectors
+	sidt (saved_idtr)
+	lidt (rmidt)
+
+	# long jump to load code selector for 16bit code (6)
+	ljmp $0x30,$0f
+0:
+	.code16
+	# disable protection
+	mov %cr0, %eax
+	and $0xfffe, %ax
+	mov %eax, %cr0
+	# load cs <- 0
+	ljmp $0,$0f
+0:	# zero data segments
+	xor %ax, %ax
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %ss
+	nop
+
+	# switch video mode by calling the video bios
+	mov $0x13, %ax
+	int $0x10
+
+	# re-enable protection
+	mov %cr0, %eax
+	or $1, %ax
+	mov %eax, %cr0
+	# long jump to load code selector for 32bit code (1)
+	ljmp $0x8,$0f
+0:
+	.code32
+	# set data selector (2) to all segment regs
+	mov $0x10, %ax
+	mov %ax, %ds
+	mov %ax, %es
+	mov %ax, %ss
+	nop
+
+	# restore 32bit interrupt descriptor table
+	lidt (saved_idtr)
+	sti
+	popal
+	ret
+
+
+	# buffer used by the track loader ... to load tracks.
 	.align 16
 buffer: