173 lines
2.6 KiB
NASM
173 lines
2.6 KiB
NASM
|
|
start:
|
|
; rsp points *at* the top element
|
|
mov rbp, 2048
|
|
mov rsp, 2048 - 2
|
|
|
|
lit interrupt_table
|
|
or rfl, rfl, 1 << Fl_Int
|
|
|
|
or rfl, Rfl, 1 << Fl_Vcd
|
|
|
|
mov16 r0, 512
|
|
mov16 r1, 1
|
|
int Int_DiskRead
|
|
|
|
main_loop:
|
|
hlt
|
|
jmp main_loop
|
|
|
|
interrupt_table:
|
|
; size
|
|
d16 1
|
|
data keyboard_interrupt
|
|
nop
|
|
|
|
keyboard_interrupt:
|
|
and rfl, rfl, !(1 << Fl_Int)
|
|
; push rbp
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], rbp
|
|
mov rbp, Rsp
|
|
; push r0
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r0
|
|
; push r1
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r1
|
|
; push r2
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r2
|
|
; push r3
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r3
|
|
|
|
in r0, Device_Keyboard
|
|
|
|
cmp r0, 44
|
|
mov r1, rfl
|
|
and r1, r1, 1 << Fl_Eq
|
|
jnz r1, .L0
|
|
|
|
cmp r0, 42
|
|
mov16 r1, rfl
|
|
and r1, r1, 1 << Fl_Eq
|
|
jnz r1, .L1
|
|
|
|
cmp r0, 40
|
|
mov r1, rfl
|
|
and r1, r1, 1 << Fl_Eq
|
|
jnz r1, .L2
|
|
|
|
jmp .L3
|
|
|
|
.L0:
|
|
mov R0, ' '
|
|
call put_char
|
|
jmp .L4
|
|
|
|
.L1:
|
|
mov r1, screen_x
|
|
cmp r1, 0
|
|
mov r2, rfl
|
|
and r2, r2, 1 << Fl_Eq
|
|
jnz r2, .L4
|
|
sub r1, r1, 1
|
|
mov screen_x, R1
|
|
; mov r0, ' '
|
|
call put_char
|
|
mov16 r1, screen_x
|
|
sub r1, r1, 1
|
|
mov screen_x, R1
|
|
jmp .L4
|
|
|
|
.L2:
|
|
mov r1, screen_y
|
|
add r1, r1, 1
|
|
mov screen_y, R1
|
|
mov r1, 0
|
|
mov screen_x, R1
|
|
jmp .L4
|
|
|
|
.L3:
|
|
add r0, r0, 'A' - 4
|
|
call put_char
|
|
jmp .L4
|
|
|
|
.L4:
|
|
|
|
; pop r3
|
|
mov r3, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
; pop r2
|
|
mov r2, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
; pop r1
|
|
mov r1, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
; pop r0
|
|
mov r0, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
mov rsp, rbp
|
|
; pop rbp
|
|
mov rbp, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
or rfl, rfl, 1 << Fl_Int
|
|
iret
|
|
|
|
put_char:
|
|
; push rbp
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], rbp
|
|
mov rbp, rsp
|
|
; push r1
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r1
|
|
; push r2
|
|
add rsp, rsp, 2
|
|
mov u16 [rsp], r2
|
|
|
|
mov r2, screen_y
|
|
mul r2, r2, vcd_width_in_ch
|
|
mov r1, screen_x
|
|
add r1, r1, 0x0c00
|
|
add r1, r1, r2
|
|
mov r1, r0
|
|
|
|
mov r1, screen_x
|
|
add r1, r1, 1
|
|
mov screen_x, r1
|
|
|
|
cmp r1, vcd_width_in_ch
|
|
mov r2, rfl
|
|
and r2, r2, 1 << Fl_Eq
|
|
jnz r2, .L0
|
|
jmp .L1
|
|
|
|
.L0:
|
|
mov r1, screen_y
|
|
add r1, r1, 1
|
|
mov screen_y, r1
|
|
mov r1, 0
|
|
mov screen_x, r1
|
|
|
|
.L1:
|
|
; pop r1
|
|
mov r1, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
; pop r2
|
|
mov r2, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
mov rsp, rbp
|
|
; pop rbp
|
|
mov rbp, u16 [rsp]
|
|
sub rsp, rsp, 2
|
|
ret
|
|
|
|
screen_x:
|
|
d16 0
|
|
screen_y:
|
|
d16 0
|
|
|
|
; vim: syntax=nasm
|