1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
|
.globl _ubox_init_isr
.globl _ubox_tick
.globl ubox_isr_wait_ticks
.globl ubox_isr_wait_tick
.globl ubox_usr_isr
.globl ___sdcc_call_hl
HTIMI_HOOK = 0xfd9f
SCNCNT = 0xf3f6
REPCNT = 0xf3f7
_ubox_init_isr::
di
ld a, l
ld (ubox_isr_wait_ticks), a
xor a
ld (ubox_isr_wait_tick), a
ld (_ubox_tick), a
ld (ubox_usr_isr), a
ld (ubox_usr_isr+1), a
ld hl, #ubox_isr
ex de, hl
ld hl, #HTIMI_HOOK
ld a, #0xc3
ld (hl), a
inc hl
ld (hl), e
inc hl
ld (hl), d
ei
ret
ubox_isr:
push af
push ix
push iy
push bc
push hl
push de
; stop BIOS reading keyboard buffer
xor a
ld (SCNCNT), a
ld (REPCNT), a
ld hl, #ubox_isr_wait_tick
inc (hl)
inc hl
inc (hl)
inc hl
inc hl
; check user isr, only MSB
ld a, (hl)
or a
jr z, no_user_isr
dec hl
ld l, (hl)
ld h, a
call ___sdcc_call_hl
no_user_isr:
pop de
pop hl
pop bc
pop iy
pop ix
pop af
ret
.area _DATA
ubox_isr_wait_ticks: .ds 1
ubox_isr_wait_tick: .ds 1
_ubox_tick: .ds 1
ubox_usr_isr: .ds 2
|
