From e552b31989dbb36f780428332be1b4958d26a37b Mon Sep 17 00:00:00 2001
From: John Tsiombikas <nuclear@member.fsf.org>
Date: Sat, 14 Apr 2018 09:28:47 +0300
Subject: [PATCH] fixed partial loading bug

---
 Makefile         |    2 +-
 src/boot/boot.s  |   36 +++++++++---------------------------
 src/boot/boot2.s |   54 +++++++++++++++++++++++++++++++++++++-----------------
 3 files changed, 47 insertions(+), 45 deletions(-)

diff --git a/Makefile b/Makefile
index 500acb6..7e0f1b0 100644
--- a/Makefile
+++ b/Makefile
@@ -37,7 +37,7 @@ $(elf): $(obj)
 
 .PHONY: clean
 clean:
-	rm -f $(obj) $(bin)
+	rm -f $(obj) $(bin) floppy.img
 
 .PHONY: cleandep
 cleandep:
diff --git a/src/boot/boot.s b/src/boot/boot.s
index 4ab605c..b9e1a76 100644
--- a/src/boot/boot.s
+++ b/src/boot/boot.s
@@ -63,10 +63,7 @@ read_sectors:
 	ret
 
 	.set VAR_ATTEMPTS, -2
-str_rdsec_msg: .asciz "rdsec: "
-str_cyl_msg: .asciz " C "
-str_head_msg: .asciz " H "
-str_sec_msg: .asciz " S "
+#str_rdsec_msg: .asciz "rdsec: "
 
 # read_sector(sidx)
 read_sector:
@@ -81,8 +78,8 @@ read_sector:
 .Lread_try:
 	# calculate the track (sidx / sectors_per_track)
 	mov 4(%bp), %ax
-	mov $str_rdsec_msg, %si
-	call print_str_num16
+#	mov $str_rdsec_msg, %si
+#	call print_str_num16
 
 	xor %dx, %dx
 	mov $SECT_PER_TRACK, %cx
@@ -101,23 +98,6 @@ read_sector:
 	inc %al
 	or %al, %cl
 
-	mov $str_cyl_msg, %si
-	mov %cx, %ax
-	rol $2, %al
-	and $3, %al
-	ror $8, %ax
-	call print_str_num16
-
-	mov $str_head_msg, %si
-	xor %ax, %ax
-	mov %dh, %al
-	call print_str_num16
-
-	mov $str_sec_msg, %si
-	mov %cl, %al
-	and $0x3f, %ax
-	call print_str_num16
-
 	# ah = 2 (read), al = 1 sectors
 	mov $0x0201, %ax
 	movb drive_number, %dl
@@ -139,13 +119,13 @@ read_sector:
 
 .Lread_ok:
 	# DBG print first dword
-	mov $str_read_error + 4, %si
-	mov %es:(%bx), %eax
-	call print_str_num
+#	mov $str_read_error + 4, %si
+#	mov %es:(%bx), %eax
+#	call print_str_num
 
 	# increment es:bx accordingly (advance es if bx overflows)
 	add $512, %bx
-	jno 0f
+	jnc 0f
 	mov %es, %ax
 	add $4096, %ax
 	mov %ax, %es
@@ -213,6 +193,7 @@ print_str:
 	ret
 
 	# expects number in eax
+	.global print_num
 print_num:
 	# save registers
 	push %es
@@ -303,6 +284,7 @@ setup_serial:
 	ret
 
 	# expects a character in al
+	.global ser_putchar
 ser_putchar:
 	push %dx
 
diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 7b8c7bb..86ee611 100644
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -2,6 +2,9 @@
 	.code16
 	.section .boot2,"a"
 
+	.extern print_num
+	.extern ser_putchar
+
 	mov $0x13, %ax
 	int $0x10
 
@@ -9,27 +12,58 @@
 	mov $logo_pal, %si
 	xor %cl, %cl
 
-0:	mov $0x3c8, %dx
+0:	xor %eax, %eax
+	mov $0x3c8, %dx
 	movb %cl, %al
 	outb %al, %dx
+	#DBG
+	call print_num
+	mov $58, %al
+	call ser_putchar
+	mov $32, %al
+	call ser_putchar
+	xor %eax, %eax
+	####
 	inc %dx
 	# red
 	movb (%si), %al
 	inc %si
 	shr $2, %al
 	outb %al, %dx
+	#DBG
+	call print_num
+	mov $32, %al
+	call ser_putchar
+	xor %eax, %eax
+	####
 	# green
 	movb (%si), %al
 	inc %si
 	shr $2, %al
 	outb %al, %dx
+	#DBG
+	call print_num
+	mov $32, %al
+	call ser_putchar
+	xor %eax, %eax
+	####
 	# blue
 	movb (%si), %al
 	inc %si
 	shr $2, %al
 	outb %al, %dx
-	inc %cl
-	jno 0b
+	#DBG
+	call print_num
+	mov $32, %al
+	call ser_putchar
+	mov $13, %al
+	call ser_putchar
+	mov $10, %al
+	call ser_putchar
+	xor %eax, %eax
+	####
+	add $1, %cl
+	jnc 0b
 
 	# copy pixels
 	pushw $0xa000
@@ -45,20 +79,6 @@
 	cli
 	hlt
 
-set_palette:
-	mov %sp, %bp
-	mov $0x3c8, %dx
-	movw 2(%bp), %ax
-	outb %al, %dx
-	inc %dx
-	movw 4(%bp), %ax
-	outb %al, %dx
-	movw 6(%bp), %ax
-	outb %al, %dx
-	movw 8(%bp), %ax
-	outb %al, %dx
-	ret
-
 logo_pal:
 	.incbin "logo.pal"
 
-- 
1.7.10.4