+# 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/>.
+
# this is the second-stage boot loader
.code16
.section .boot2,"a"
+ .extern ser_putchar
+
mov $0x13, %ax
int $0x10
+ movb $10, %al
+ call ser_putchar
+
# copy palette
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 ser_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 ser_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 ser_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 ser_print_num
+ mov $32, %al
+ call ser_putchar
+ mov $10, %al
+ call ser_putchar
+ xor %eax, %eax
+ ####
+ add $1, %cl
+ jnc 0b
# copy pixels
pushw $0xa000
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
+ # expects string pointer in ds:si
+ser_print_str:
+ pusha
+
+0: mov (%si), %al
+ cmp $0, %al
+ jz .Lend
+ call ser_putchar
+ inc %si
+ jmp 0b
+
+.Lend: popa
+ ret
+
+
+ # expects number in eax
+ser_print_num:
+ # save registers
+ pusha
+
+ movw $numbuf + 16, %si
+ movb $0, (%si)
+ mov $10, %ebx
+.Lconvloop:
+ xor %edx, %edx
+ div %ebx
+ add $48, %dl
+ dec %si
+ mov %dl, (%si)
+ cmp $0, %eax
+ jnz .Lconvloop
+
+ call ser_print_str
+
+ # restore regs
+ popa
ret
+numbuf: .space 16
+
logo_pal:
.incbin "logo.pal"