+# pcboot - bootable PC demo/game kernel
+# Copyright (C) 2018 John Tsiombikas <nuclear@member.fsf.org>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY, without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <https://www.gnu.org/licenses/>.
+
.code16
- .section .boot,"a"
+ .section .boot,"ax"
.set stack_top, 0x7be0
.set read_retries, 0x7be8
mov $_boot2_size, %eax
call print_num
+ mov $_boot2_size, %eax
mov %eax, %ebx
shr $9, %eax
and $0x1ff, %ebx
call read_sectors
jmp boot2_addr
- .set ARG_NSECT, 6
- .set ARG_SIDX, 4
-
loading_msg: .asciz "\nLoad "
-driveno_msg: .asciz "Drive: "
+driveno_msg: .asciz "Drv:"
+ .global sect_per_track
sect_per_track: .short 18
+ .global num_cylinders
num_cylinders: .short 80
+ .global num_heads
num_heads: .short 2
+ .global heads_mask
heads_mask: .byte 1
get_drive_chs:
mov $8, %ah
int $0x13
- jnc .Lok
+ jnc ok
ret
-.Lok: xor %eax, %eax
+ok: xor %eax, %eax
mov %ch, %al
mov %cl, %ah
rol $2, %ah
call print_num
ret
+
+ .set ARG_NSECT, 6
+ .set ARG_SIDX, 4
+
# read_sectors(first, num)
read_sectors:
push %bp
movw $3, read_retries
-.Lread_try:
+read_try:
# calculate the track (sidx / sectors_per_track)
mov 4(%bp), %ax
mov $0x0201, %ax
movb drive_number, %dl
int $0x13
- jnc .Lread_ok
+ jnc read_ok
# abort after 3 attempts
decw read_retries
- jz .Lread_fail
+ jz read_fail
# error detected, reset controller and retry
xor %ah, %ah
int $0x13
- jmp .Lread_try
+ jmp read_try
-.Lread_fail:
+read_fail:
mov 4(%bp), %ax
jmp abort_read
-.Lread_ok:
+read_ok:
mov $46, %ax
call print_char
pop %bp
ret
-str_read_error: .asciz "rderr: "
+str_read_error: .asciz "rderr:"
abort_read:
mov $str_read_error, %si
0: mov (%si), %al
cmp $0, %al
- jz .Lend
+ jz end
call print_char
inc %si
jmp 0b
-.Lend: popa
+end: popa
ret
# expects character in al
print_char:
push %es
- pushw $0xb800
+
+ push %ax
+ cmp $10, %ax
+ jnz 0f
+ mov $32, %ax
+
+0: pushw $0xb800
pop %es
movw cursor_x, %di
shl $1, %di
movb $7, %es:1(%di)
incw cursor_x
+ pop %ax
call ser_putchar
pop %es
ret
movw $scratchbuf + scratchbuf_size, %si
movb $0, (%si)
mov $10, %ebx
-.Lconvloop:
+convloop:
xor %edx, %edx
div %ebx
add $48, %dl
dec %si
mov %dl, (%si)
cmp $0, %eax
- jnz .Lconvloop
+ jnz convloop
call print_str
.set DIV_9600, 115200 / 9600
.set LCTL_8N1, 0x03
.set LCTL_DLAB, 0x80
- .set FIFO_ENABLE, 0x01
- .set FIFO_SEND_CLEAR, 0x04
- .set FIFO_RECV_CLEAR, 0x02
- .set MCTL_DTR, 0x01
- .set MCTL_RTS, 0x02
- .set MCTL_OUT2, 0x08
+ .set FIFO_ENABLE_CLEAR, 0x07
+ .set MCTL_DTR_RTS_OUT2, 0x0b
.set LST_TREG_EMPTY, 0x20
setup_serial:
mov $UART_LCTL, %dx
out %al, %dx
# clear and enable fifo
- mov $FIFO_ENABLE, %al
- or $FIFO_SEND_CLEAR, %al
- or $FIFO_RECV_CLEAR, %al
+ mov $FIFO_ENABLE_CLEAR, %al
mov $UART_FIFO, %dx
out %al, %dx
# assert RTS and DTR
- mov $MCTL_DTR, %al
- or $MCTL_RTS, %al
- or $MCTL_OUT2, %al
+ mov $MCTL_DTR_RTS_OUT2, %al
mov $UART_MCTL, %dx
out %al, %dx
ret
# expects a character in al
- .global ser_putchar
ser_putchar:
push %dx
0: mov %al, %ah
# wait until the transmit register is empty
mov $UART_LSTAT, %dx
-.Lwait: in %dx, %al
+wait: in %dx, %al
and $LST_TREG_EMPTY, %al
- jz .Lwait
+ jz wait
mov $UART_DATA, %dx
mov %ah, %al
out %al, %dx