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more debugging
author
John Tsiombikas
<nuclear@member.fsf.org>
Wed, 11 Apr 2018 15:30:15 +0000
(18:30 +0300)
committer
John Tsiombikas
<nuclear@member.fsf.org>
Wed, 11 Apr 2018 15:30:15 +0000
(18:30 +0300)
src/boot/boot.s
patch
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blob
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history
diff --git
a/src/boot/boot.s
b/src/boot/boot.s
index
8ba4a11
..
4ab605c
100644
(file)
--- a/
src/boot/boot.s
+++ b/
src/boot/boot.s
@@
-1,12
+1,15
@@
.code16
.section .boot,"a"
.code16
.section .boot,"a"
+ .set scratchbuf, 0x7b00
+
+boot:
cli
cld
# move stack to just below the code
xor %ax, %ax
mov %ax, %ss
cli
cld
# move stack to just below the code
xor %ax, %ax
mov %ax, %ss
- mov $0x7c00, %sp
+ mov $0x7b00, %sp
# use the code segment for data access
mov %cs, %ax
mov %ax, %ds
# use the code segment for data access
mov %cs, %ax
mov %ax, %ds
@@
-16,9
+19,6
@@
call setup_serial
call setup_serial
- mov $_boot2_size, %eax
- call print_num
-
# load the second stage boot loader and jump to it
mov $_boot2_size, %eax
mov %eax, %ebx
# load the second stage boot loader and jump to it
mov $_boot2_size, %eax
mov %eax, %ebx
@@
-37,9
+37,6
@@
call read_sectors
jmp boot2_addr
call read_sectors
jmp boot2_addr
- cli
- hlt
-
.set SECT_PER_TRACK, 18
.set ARG_NSECT, 6
.set SECT_PER_TRACK, 18
.set ARG_NSECT, 6
@@
-141,6
+138,11
@@
read_sector:
jmp abort_read
.Lread_ok:
jmp abort_read
.Lread_ok:
+ # DBG print first dword
+ 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
# increment es:bx accordingly (advance es if bx overflows)
add $512, %bx
jno 0f
@@
-154,12
+156,11
@@
read_sector:
pop %bp
ret
pop %bp
ret
-str_read_error: .asciz "err read sector: "
+str_read_error: .asciz "err read sect: "
abort_read:
mov $str_read_error, %si
call print_str_num16
abort_read:
mov $str_read_error, %si
call print_str_num16
- cli
hlt
cursor_x: .byte 0
hlt
cursor_x: .byte 0
@@
-170,6
+171,8
@@
print_str_num:
call print_str
pop %eax
call print_num
call print_str
pop %eax
call print_num
+ mov $13, %al
+ call ser_putchar
mov $10, %al
call ser_putchar
ret
mov $10, %al
call ser_putchar
ret
@@
-216,7
+219,7
@@
print_num:
pusha
xor %cx, %cx
pusha
xor %cx, %cx
- movw $numbuf, %si
+ movw $scratchbuf, %si
mov $10, %ebx
0: xor %edx, %edx
mov $10, %ebx
0: xor %edx, %edx
@@
-328,7
+331,6
@@
ser_putstr:
drive_number: .byte 0
drive_number: .byte 0
-numbuf: .space 8
.org 510
.byte 0x55
.byte 0xaa
.org 510
.byte 0x55
.byte 0xaa