fixed USB booting issue

diff --git a/src/boot/boot.s b/src/boot/boot.s
index 2202800..7f8ee68 100644 (file)
--- a/src/boot/boot.s
+++ b/src/boot/boot.s
@@ -1,16 +1,19 @@
        .code16
        .section .boot,"a"
 
        .code16
        .section .boot,"a"
 

+       .set stack_top, 0x7be0
+       .set read_retries, 0x7be8
+       .set drive_number, 0x7bec
+       .set cursor_x, 0x7bee

        .set scratchbuf, 0x7bf0
        .set scratchbuf_size, 16
 
 boot:
        cli
        .set scratchbuf, 0x7bf0
        .set scratchbuf_size, 16
 
 boot:
        cli

-       cld

        # move stack to just below the code
        xor %ax, %ax
        mov %ax, %ss
        # move stack to just below the code
        xor %ax, %ax
        mov %ax, %ss

-       mov $0x7bf0, %sp
+       mov $stack_top, %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

@@ -20,14 +23,14 @@ boot:
 
        call setup_serial
 
 
        call setup_serial
 

+       call get_drive_chs
+

        mov $loading_msg, %si
        call print_str
 
        # load the second stage boot loader and jump to it
        mov $_boot2_size, %eax
        call print_num
        mov $loading_msg, %si
        call print_str
 
        # load the second stage boot loader and jump to it
        mov $_boot2_size, %eax
        call print_num

-       mov $loading_msg2, %si
-       call print_str

 
        mov %eax, %ebx
        shr $9, %eax
 
        mov %eax, %ebx
        shr $9, %eax

@@ -45,13 +48,11 @@ boot:
        call read_sectors
        jmp boot2_addr
 
        call read_sectors
        jmp boot2_addr
 

-       .set SECT_PER_TRACK, 18
-

        .set ARG_NSECT, 6
        .set ARG_SIDX, 4
 
        .set ARG_NSECT, 6
        .set ARG_SIDX, 4
 

-loading_msg: .asciz "Loading "
-loading_msg2: .asciz " bytes\n"
+loading_msg: .asciz "\nLoad "
+driveno_msg: .asciz "Drive: "

 
 sect_per_track: .short 18
 num_cylinders: .short 80
 
 sect_per_track: .short 18
 num_cylinders: .short 80

@@ -59,26 +60,45 @@ num_heads: .short 2
 heads_mask: .byte 1
 
 get_drive_chs:
 heads_mask: .byte 1
 
 get_drive_chs:

+       mov $driveno_msg, %si
+       call print_str
+       xor %eax, %eax

        movb drive_number, %dl
        movb drive_number, %dl

+       mov %dl, %al
+       call print_num
+       mov $10, %al
+       call print_char
+

        mov $8, %ah
        int $0x13
        jnc .Lok
        ret
 
        mov $8, %ah
        int $0x13
        jnc .Lok
        ret
 

-.Lok:  mov %ch, %al
+.Lok:  xor %eax, %eax
+       mov %ch, %al

        mov %cl, %ah
        rol $2, %ah
        mov %cl, %ah
        rol $2, %ah

+       inc %ax

        and $0x3ff, %ax
        mov %ax, num_cylinders
 
        and $0x3ff, %ax
        mov %ax, num_cylinders
 

+       and $0x3f, %cx

        mov %cx, sect_per_track
        mov %cx, sect_per_track

-       andw $0x3f, sect_per_track

 
        shr $8, %dx
 
        shr $8, %dx

-       mov %dx, num_heads
-       dec %dl

        mov %dl, heads_mask
        mov %dl, heads_mask

+       inc %dx
+       mov %dx, num_heads

 
 

+       call print_num
+       mov $47, %al
+       call print_char
+       mov %dx, %ax
+       call print_num
+       mov $47, %al
+       call print_char
+       mov %cx, %ax
+       call print_num

        ret
 
 # read_sectors(first, num)
        ret
 
 # read_sectors(first, num)

@@ -101,17 +121,14 @@ read_sectors:
        pop %bp
        ret
 
        pop %bp
        ret
 

-       .set VAR_ATTEMPTS, -2
-

 # read_sector(sidx)
 read_sector:
        push %bp
        mov %sp, %bp
 # read_sector(sidx)
 read_sector:
        push %bp
        mov %sp, %bp

-       sub $2, %sp

        push %cx
        push %dx
 
        push %cx
        push %dx
 

-       movw $3, VAR_ATTEMPTS(%bp)
+       movw $3, read_retries

 
 .Lread_try:
        # calculate the track (sidx / sectors_per_track)
 
 .Lread_try:
        # calculate the track (sidx / sectors_per_track)

@@ -148,7 +165,7 @@ read_sector:
        jnc .Lread_ok
 
        # abort after 3 attempts
        jnc .Lread_ok
 
        # abort after 3 attempts

-       decw VAR_ATTEMPTS(%bp)
+       decw read_retries

        jz .Lread_fail
 
        # error detected, reset controller and retry
        jz .Lread_fail
 
        # error detected, reset controller and retry

@@ -173,33 +190,19 @@ read_sector:
 
 0:     pop %dx
        pop %cx
 
 0:     pop %dx
        pop %cx

-       add $2, %sp

        pop %bp
        ret
 
        pop %bp
        ret
 

-str_read_error: .asciz "read error, sector: "
+str_read_error: .asciz "rderr: "

 
 abort_read:
        mov $str_read_error, %si
 
 abort_read:
        mov $str_read_error, %si

-       call print_str_num16
-       hlt
-
-       # prints a string (ds:si) followed by a number (eax)
-print_str_num:
-       push %eax

        call print_str
        call print_str

-       pop %eax
+       and $0xffff, %eax

        call print_num
        mov $10, %al
        call print_num
        mov $10, %al

-       call ser_putchar
-       ret
-
-print_str_num16:
-       push %eax
-       and $0xffff, %eax
-       call print_str_num
-       pop %eax
-       ret
+       call print_char
+       hlt

 
        # expects string pointer in ds:si
 print_str:
 
        # expects string pointer in ds:si
 print_str:

@@ -231,8 +234,6 @@ print_char:
        pop %es
        ret
 
        pop %es
        ret
 

-cursor_x: .short 0
-

        # expects number in eax
        .global print_num
 print_num:
        # expects number in eax
        .global print_num
 print_num:

@@ -329,10 +330,7 @@ ser_putchar:
        pop %dx
        ret
        
        pop %dx
        ret
        

-
-drive_number: .byte 0

        .org 510
        .byte 0x55
        .byte 0xaa
        .org 510
        .byte 0x55
        .byte 0xaa

-

 boot2_addr:
 boot2_addr:

diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 838af46..ab5c6ad 100644 (file)
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -7,6 +7,9 @@
        mov $0x13, %ax
        int $0x10
 
        mov $0x13, %ax
        int $0x10
 

+       movb $10, %al
+       call ser_putchar
+

        # copy palette
        mov $logo_pal, %si
        xor %cl, %cl
        # copy palette
        mov $logo_pal, %si
        xor %cl, %cl