.code16
.section .boot2,"a"
+ .set main_load_addr, 0x100000
+
# make sure any BIOS call didn't re-enable interrupts
cli
- # just in case we were loaded from floppy, turn all floppy motors off
- call motor_off
+ # enter unreal mode
+ call unreal
+
+ movb $10, %al
+ call ser_putchar
+
+ call clearscr
+
+ # enable A20 address line
+ call enable_a20
+
+ # load the whole program into memory starting at 1MB
+ call load_main
mov $0x13, %ax
int $0x10
- # load initial GDT/IDT
+ # load initial GDT
lgdt (gdt_lim)
+ # load initial IDT
lidt (idt_lim)
- # enable protection
+
+ # enter protected mode for the first time
mov %cr0, %eax
or $1, %eax
mov %eax, %cr0
mov %ax, %gs
mov %ax, %fs
- movb $10, %al
- call ser_putchar
-
- call clearscr
-
- mov $hello, %esi
- call putstr
-
- # enable A20 line
- call enable_a20
-
- call logohack
+ jmp main_load_addr
cli
- hlt
+0: hlt
+ jmp 0b
+
-hello: .asciz "Switched to 32bit\n"
.align 4
gdt_lim: .word 23
call putchar
hlt
-ena20_msg: .asciz "A20 line enabled\n"
+ .code16
+unreal:
+ # use the same GDT above, will use data segment: 2
+ lgdt (gdt_lim)
-enable_a20:
- call test_a20
- jnc a20done
- call enable_a20_kbd
- call test_a20
- jnc a20done
- call enable_a20_fast
- call test_a20
- jnc a20done
- # keep trying ... we can't do anything useful without A20 anyway
- jmp enable_a20
-a20done:
- mov $ena20_msg, %esi
- call putstr
- ret
+ mov %cr0, %eax
+ or $1, %ax
+ mov %eax, %cr0
+ jmp 0f
- # CF = 1 if A20 test fails (not enabled)
-test_a20:
- mov $0x07c000, %ebx
- mov $0x17c000, %edx
- movl $0xbaadf00d, (%ebx)
- movl $0xaabbcc42, (%edx)
- subl $0xbaadf00d, (%ebx)
+0: mov $0x10, %ax
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %fs
+ mov %ax, %gs
+ mov %ax, %ss
+
+ mov %cr0, %eax
+ and $0xfffe, %ax
+ mov %eax, %cr0
+
+ xor %ax, %ax
+ mov %ax, %ds
+ mov %ax, %es
+ mov %ax, %fs
+ mov %ax, %gs
+ mov %ax, %ss
ret
- # enable A20 line through port 0x92 (fast A20)
-enable_a20_fast:
- mov $ena20_fast_msg, %esi
+mainsz_msg: .asciz "Main program size: "
+mainsz_msg2: .asciz " ("
+mainsz_msg3: .asciz " sectors)\n"
+
+first_sect: .long 0
+sect_left: .long 0
+cur_track: .long 0
+trk_sect: .long 0
+dest_ptr: .long 0
+
+load_main:
+ movl $main_load_addr, dest_ptr
+
+ # calculate first sector
+ mov $_boot2_size, %eax
+ add $511, %eax
+ shr $9, %eax
+ # add 1 to account for the boot sector
+ inc %eax
+ mov %eax, first_sect
+
+ # calculate the first track (first_sect / sect_per_track)
+ movzxw sect_per_track, %ecx
+ xor %edx, %edx
+ div %ecx
+ mov %eax, cur_track
+ # remainder is sector within track
+ mov %edx, trk_sect
+
+ mov $mainsz_msg, %esi
call putstr
+ mov $_main_size, %eax
+ mov %eax, %ecx
+ call print_num
+
+ mov $mainsz_msg2, %esi
+ call putstr
+
+ # calculate sector count
+ add $511, %eax
+ shr $9, %eax
+ mov %eax, sect_left
+
+ call print_num
+ mov $mainsz_msg3, %esi
+ call putstr
+
+ # read a whole track into the buffer (or partial first track)
+ldloop:
+ movzxw sect_per_track, %ecx
+ sub trk_sect, %ecx
+ push %ecx
+ call read_track
+
+ mov buffer, %eax
+ call print_num
+ mov $10, %al
+ call putchar
+
+ # copy to high memory
+ mov $buffer, %esi
+ mov dest_ptr, %edi
+ mov (%esp), %ecx
+ shl $9, %ecx
+ add %ecx, dest_ptr
+ shr $2, %ecx
+ addr32 rep movsl
+
+ incl cur_track
+ # other than the first track which might be partial, all the rest start from 0
+ movl $0, trk_sect
+
+ pop %ecx
+ sub %ecx, sect_left
+ ja ldloop
+
+ # the BIOS might have enabled interrupts
+ cli
+
+ # just in case we were loaded from floppy, turn all floppy motors off
+ mov $0x3f2, %dx
+ in %dx, %al
+ and $0xf0, %al
+ out %al, %dx
+
+ mov $10, %ax
+ call putchar
+
+ # DBG
+ hlt
- in $0x92, %al
- or $2, %al
- out %al, $0x92
ret
-ena20_fast_msg: .asciz "Attempting fast A20 enable\n"
+rdtrk_msg: .asciz "Reading track: "
+rdcyl_msg: .asciz " - cyl: "
+rdhead_msg: .asciz " head: "
+rdsect_msg: .asciz " start sect: "
+read_retries: .short 0
- # enable A20 line through the keyboard controller
- .set KBC_DATA_PORT, 0x60
- .set KBC_CMD_PORT, 0x64
- .set KBC_STATUS_PORT, 0x64
- .set KBC_CMD_RD_OUTPORT, 0xd0
- .set KBC_CMD_WR_OUTPORT, 0xd1
+ .set drive_number, 0x7bec
+read_track:
+ # set es to the start of the destination buffer to allow reading in
+ # full 64k chunks if necessary
+ mov $buffer, %bx
+ shr $4, %bx
+ mov %bx, %es
+ xor %ebx, %ebx
- .set KBC_STAT_OUT_RDY, 0x01
- .set KBC_STAT_IN_FULL, 0x02
+ movw $3, read_retries
-enable_a20_kbd:
- mov $ena20_kbd_msg, %esi
+read_try:
+ # print track
+ mov $rdtrk_msg, %esi
+ call putstr
+ mov cur_track, %eax
+ call print_num
+ mov $rdcyl_msg, %esi
call putstr
- call kbc_wait_write
- mov $KBC_CMD_WR_OUTPORT, %al
- out %al, $KBC_CMD_PORT
- call kbc_wait_write
- mov $0xdf, %al
- out %al, $KBC_DATA_PORT
- ret
+ # calc cylinder (cur_track / num_heads) and head (cur_track % num_heads)
+ mov cur_track, %eax
+ movzxw num_heads, %ecx
+ xor %edx, %edx
+ div %ecx
-ena20_kbd_msg: .asciz "Attempting KBD A20 enable\n"
+ # print cylinder
+ push %eax
+ call print_num
+ # print head
+ mov $rdhead_msg, %esi
+ call putstr
+ movzx %dx, %eax
+ call print_num
+ pop %eax
- # wait until the keyboard controller is ready to accept another byte
-kbc_wait_write:
- in $KBC_STATUS_PORT, %al
- and $KBC_STAT_IN_FULL, %al
- jnz kbc_wait_write
+ # head in dh
+ mov %dl, %dh
+
+ # cylinder low byte at ch and high bits at cl[7, 6]
+ mov %al, %ch
+ mov %ah, %cl
+ and $3, %cl
+ ror $2, %cl
+
+ # print start sector
+ mov $rdsect_msg, %esi
+ call putstr
+ mov trk_sect, %eax
+ call print_num
+ mov $10, %al
+ call putchar
+
+ # start sector (1-based) in cl[0, 5]
+ mov trk_sect, %al
+ inc %al
+ and $0x3f, %al
+ or %al, %cl
+
+ # number of sectors in al
+ mov 2(%esp), %ax
+ # call number (2) in ah
+ mov $2, %ah
+ # drive number in dl
+ movb drive_number, %dl
+ int $0x13
+ jnc read_ok
+
+ # abort after 3 attempts
+ decw read_retries
+ jz read_fail
+
+ # error, reset controller and retry
+ xor %ah, %ah
+ int $0x13
+ jmp read_try
+
+read_fail:
+ jmp abort_read
+
+read_ok:
+ mov $35, %ax
+ call putchar
+
+ # reset es to 0 before returning
+ xor %ax, %ax
+ mov %ax, %es
ret
+str_read_error: .asciz "Read error while reading track: "
+
+abort_read:
+ mov $str_read_error, %esi
+ call putstr
+ mov cur_track, %eax
+ call print_num
+ mov $10, %al
+ call putchar
+
+ cli
+0: hlt
+ jmp 0b
+
+
+
# better print routines, since we're not constrainted by the 512b of
# the boot sector.
cursor_x: .long 0
scrollup:
pusha
- # move 80 * 24 lines from b8050 -> b8000
+ # move 80 * 24 lines from b80a0 -> b8000
mov $0xb8000, %edi
- mov $0xb8050, %esi
- mov $480, %ecx
- rep movsl
- # clear last line (b8780)
- mov $0xb8780, %edi
+ mov $0xb80a0, %esi
+ mov $960, %ecx
+ addr32 rep movsl
+ # clear last line (b8f00)
+ mov $0xb8f00, %edi
xor %eax, %eax
- mov $20, %ecx
- rep stosl
+ mov $40, %ecx
+ addr32 rep stosl
popa
ret
clearscr:
mov $0xb8000, %edi
xor %eax, %eax
- mov $500, %ecx
- rep stosl
+ mov $1000, %ecx
+ addr32 rep stosl
ret
.set UART_DATA, 0x3f8
ret
-motor_off:
- mov $0x3f2, %dx
- in %dx, %al
- and $0xf0, %al
- out %al, %dx
+
+ena20_msg: .asciz "A20 line enabled\n"
+
+enable_a20:
+ call test_a20
+ jnc a20done
+ call enable_a20_kbd
+ call test_a20
+ jnc a20done
+ call enable_a20_fast
+ call test_a20
+ jnc a20done
+ # keep trying ... we can't do anything useful without A20 anyway
+ jmp enable_a20
+a20done:
+ mov $ena20_msg, %esi
+ call putstr
ret
-logohack:
- # copy palette
- mov $logo_pal, %esi
- xor %cl, %cl
-
-0: xor %eax, %eax
- mov $0x3c8, %dx
- movb %cl, %al
- outb %al, %dx
- inc %dx
- # red
- movb (%esi), %al
- inc %esi
- shr $2, %al
- outb %al, %dx
- # green
- movb (%esi), %al
- inc %esi
- shr $2, %al
- outb %al, %dx
- # blue
- movb (%esi), %al
- inc %esi
- shr $2, %al
- outb %al, %dx
- add $1, %cl
- jnc 0b
-
- # copy pixels
- mov $sintab, %ebp
- mov $logo_pix, %esi
-frameloop:
- mov $0xa0000, %edi
- movl $0, yval
-yloop:
- movl $0, xval
-xloop:
- # calc src scanline address -> ebx
- xor %ecx, %ecx
- mov yval, %ebx
- shl $2, %ebx
- add frameno, %ebx
- and $0xff, %ebx
- mov (%ebp, %ebx), %cl
- shr $5, %ecx
-
- mov yval, %eax
- add %ecx, %eax
- # bounds check
- cmp $200, %eax
- jl 0f
- mov $199, %eax
-
-0: mov %eax, %ebx
- shl $8, %eax
- shl $6, %ebx
- add %eax, %ebx
-
- # calc src x offset -> eax
- xor %ecx, %ecx
- mov xval, %eax
- shl $2, %eax
- add frameno, %eax
- and $0xff, %eax
- mov (%ebp, %eax), %cl
- shr $5, %ecx
-
- mov xval, %eax
- add %ecx, %eax
- # bounds check
- cmp $320, %eax
- jl 0f
- mov $319, %eax
-
-0: add %eax, %ebx
- mov (%ebx, %esi), %al
-
- mov %al, (%edi)
- inc %edi
-
- incl xval
- cmpl $320, xval
- jnz xloop
-
- incl yval
- cmpl $200, yval
- jnz yloop
-
- incl frameno
-
- # wait vsync
- mov $0x3da, %dx
-0: in %dx, %al
- and $8, %al
- jnz 0b
-0: in %dx, %al
- and $8, %al
- jz 0b
- jmp frameloop
-
-xval: .long 0
-yval: .long 0
-frameno: .long 0
+ # CF = 1 if A20 test fails (not enabled)
+test_a20:
+ mov $0x07c000, %ebx
+ mov $0x17c000, %edx
+ movl $0xbaadf00d, (%ebx)
+ movl $0xaabbcc42, (%edx)
+ subl $0xbaadf00d, (%ebx)
+ ret
-numbuf: .space 16
+ # enable A20 line through port 0x92 (fast A20)
+enable_a20_fast:
+ mov $ena20_fast_msg, %esi
+ call putstr
+
+ in $0x92, %al
+ or $2, %al
+ out %al, $0x92
+ ret
+
+ena20_fast_msg: .asciz "Attempting fast A20 enable\n"
+
+
+ # enable A20 line through the keyboard controller
+ .set KBC_DATA_PORT, 0x60
+ .set KBC_CMD_PORT, 0x64
+ .set KBC_STATUS_PORT, 0x64
+ .set KBC_CMD_RD_OUTPORT, 0xd0
+ .set KBC_CMD_WR_OUTPORT, 0xd1
+
+ .set KBC_STAT_OUT_RDY, 0x01
+ .set KBC_STAT_IN_FULL, 0x02
+
+enable_a20_kbd:
+ mov $ena20_kbd_msg, %esi
+ call putstr
+
+ call kbc_wait_write
+ mov $KBC_CMD_WR_OUTPORT, %al
+ out %al, $KBC_CMD_PORT
+ call kbc_wait_write
+ mov $0xdf, %al
+ out %al, $KBC_DATA_PORT
+ ret
+
+ena20_kbd_msg: .asciz "Attempting KBD A20 enable\n"
+
+ # wait until the keyboard controller is ready to accept another byte
+kbc_wait_write:
+ in $KBC_STATUS_PORT, %al
+ and $KBC_STAT_IN_FULL, %al
+ jnz kbc_wait_write
+ ret
-logo_pal:
- .incbin "logo.pal"
+numbuf: .space 16
.align 16
-logo_pix:
- .incbin "logo.raw"
-
-sintab:
- .byte 127
- .byte 130
- .byte 133
- .byte 136
- .byte 139
- .byte 143
- .byte 146
- .byte 149
- .byte 152
- .byte 155
- .byte 158
- .byte 161
- .byte 164
- .byte 167
- .byte 170
- .byte 173
- .byte 176
- .byte 179
- .byte 182
- .byte 184
- .byte 187
- .byte 190
- .byte 193
- .byte 195
- .byte 198
- .byte 200
- .byte 203
- .byte 205
- .byte 208
- .byte 210
- .byte 213
- .byte 215
- .byte 217
- .byte 219
- .byte 221
- .byte 224
- .byte 226
- .byte 228
- .byte 229
- .byte 231
- .byte 233
- .byte 235
- .byte 236
- .byte 238
- .byte 239
- .byte 241
- .byte 242
- .byte 244
- .byte 245
- .byte 246
- .byte 247
- .byte 248
- .byte 249
- .byte 250
- .byte 251
- .byte 251
- .byte 252
- .byte 253
- .byte 253
- .byte 254
- .byte 254
- .byte 254
- .byte 254
- .byte 254
- .byte 255
- .byte 254
- .byte 254
- .byte 254
- .byte 254
- .byte 254
- .byte 253
- .byte 253
- .byte 252
- .byte 251
- .byte 251
- .byte 250
- .byte 249
- .byte 248
- .byte 247
- .byte 246
- .byte 245
- .byte 244
- .byte 242
- .byte 241
- .byte 239
- .byte 238
- .byte 236
- .byte 235
- .byte 233
- .byte 231
- .byte 229
- .byte 228
- .byte 226
- .byte 224
- .byte 221
- .byte 219
- .byte 217
- .byte 215
- .byte 213
- .byte 210
- .byte 208
- .byte 205
- .byte 203
- .byte 200
- .byte 198
- .byte 195
- .byte 193
- .byte 190
- .byte 187
- .byte 184
- .byte 182
- .byte 179
- .byte 176
- .byte 173
- .byte 170
- .byte 167
- .byte 164
- .byte 161
- .byte 158
- .byte 155
- .byte 152
- .byte 149
- .byte 146
- .byte 143
- .byte 139
- .byte 136
- .byte 133
- .byte 130
- .byte 127
- .byte 124
- .byte 121
- .byte 118
- .byte 115
- .byte 111
- .byte 108
- .byte 105
- .byte 102
- .byte 99
- .byte 96
- .byte 93
- .byte 90
- .byte 87
- .byte 84
- .byte 81
- .byte 78
- .byte 75
- .byte 72
- .byte 70
- .byte 67
- .byte 64
- .byte 61
- .byte 59
- .byte 56
- .byte 54
- .byte 51
- .byte 49
- .byte 46
- .byte 44
- .byte 41
- .byte 39
- .byte 37
- .byte 35
- .byte 33
- .byte 30
- .byte 28
- .byte 26
- .byte 25
- .byte 23
- .byte 21
- .byte 19
- .byte 18
- .byte 16
- .byte 15
- .byte 13
- .byte 12
- .byte 10
- .byte 9
- .byte 8
- .byte 7
- .byte 6
- .byte 5
- .byte 4
- .byte 3
- .byte 3
- .byte 2
- .byte 1
- .byte 1
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 0
- .byte 1
- .byte 1
- .byte 2
- .byte 3
- .byte 3
- .byte 4
- .byte 5
- .byte 6
- .byte 7
- .byte 8
- .byte 9
- .byte 10
- .byte 12
- .byte 13
- .byte 15
- .byte 16
- .byte 18
- .byte 19
- .byte 21
- .byte 23
- .byte 25
- .byte 26
- .byte 28
- .byte 30
- .byte 33
- .byte 35
- .byte 37
- .byte 39
- .byte 41
- .byte 44
- .byte 46
- .byte 49
- .byte 51
- .byte 54
- .byte 56
- .byte 59
- .byte 61
- .byte 64
- .byte 67
- .byte 70
- .byte 72
- .byte 75
- .byte 78
- .byte 81
- .byte 84
- .byte 87
- .byte 90
- .byte 93
- .byte 96
- .byte 99
- .byte 102
- .byte 105
- .byte 108
- .byte 111
- .byte 115
- .byte 118
- .byte 121
- .byte 124
+buffer: