From 9ee980bc94c6415f9a21f314c257ea4b87b2eec6 Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Sun, 17 Aug 2003 22:01:00 -0400
Subject: [PATCH] Import backup from 2003-08-17_2

---
 bootdef.inc |  1 -
 stage2.asm  | 47 ++++++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/bootdef.inc b/bootdef.inc
index 4829168..47e4e1e 100644
--- a/bootdef.inc
+++ b/bootdef.inc
@@ -16,7 +16,6 @@
 %define BOOT_VESA_OEM	0x0004		;258 - null-terminated OEM identification string
 %define BOOT_VESA_VBE	0x0106		;512 - copy of VESA VBEInfoBlock
 %define	BOOT_VESA_INFO	0x0306		;256 - copy of VESA ModeInfoBlock for selected mode
-%define BOOT_VESA_LFB	0x0406		;1 - boolean: are we using LFB or not
 
 
 
diff --git a/stage2.asm b/stage2.asm
index b67b614..5e2b356 100644
--- a/stage2.asm
+++ b/stage2.asm
@@ -195,7 +195,16 @@ copydisk_loop:
 	loop	read_cylinder
 
 ;------------------------------------------------------
-no_rd:						;done with ram disk, on to vesa info...
+no_rd:
+	xor	ax, ax
+	mov	ds, ax
+	mov	dx, 4				;we'll assume the system has 4 megabytes of RAM...
+	mov	esi, 0x3FFFFC			;4 bytes under 4 MB
+
+
+
+
+						;on to vesa info...
 	xor	ax, ax
 	mov	gs, ax
 	mov	ds, ax
@@ -389,6 +398,7 @@ vesa_getchoice:
 	mov	si, cx				;ds:si points to word containing selected mode#
 	lodsw
 	mov	cx, ax
+	mov	dx, ax				;cx and dx hold mode#
 
 	mov	ax, VESA_MODEINFO_SEG
 	mov	es, ax
@@ -397,11 +407,40 @@ vesa_getchoice:
 	int	0x10
 	call	checkvesa
 
-	mov	dx, 20
-	call	vesa_showmodeinfo
+	mov	ax, VESA_MODEINFO_SEG
+	mov	ds, ax
+	xor	si, si
+	mov	ax, BOOT_DATA_SEG
+	mov	es, ax
+	mov	di, BOOT_VESA_INFO
+	mov	cx, 256
+vesa_copymodeinfo_loop:
+	lodsb
+	stosb
+	loop	vesa_copymodeinfo_loop		;store ModeInfoBlock for current
 
+	mov	[es:BOOT_VESA], dx		;store mode# for kernel
+
+	mov	ax, 0xb800
+	mov	es, ax
+	xor	di, di
+	mov	al, dh
+	call	puthex2
+	mov	al, dl
+	call	puthex2
+
+	mov	bx, dx
+	or	bx, 0x4000			;set "use LFB" bit of mode#
+	mov	ax, 0x4F02
+	int	0x10				;switch to graphics mode!!!
+	call	checkvesa
+
+	jmp	vesa_done
 
 vesa_consolemode_only:
+	mov	ax, BOOT_DATA_SEG
+	mov	es, ax
+	mov	word [es:BOOT_VESA], 0
 
 	jmp	vesa_done
 
@@ -493,6 +532,8 @@ checkmode:
 	jz	vesa_modenogood
 	test	al, 0x10			;graphics mode
 	jz	vesa_modenogood
+	test	al, 0x80			;Linear Frame Buffer supported
+	jz	vesa_modenogood
 	mov	al, [es:di+25]			;BitsPerPixel
 	cmp	al, 16
 	jz	vesa_bppok