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
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
;
; Ullrich von Bassewitz, 06.08.1998
;
; char cgetc (void);
;
.export _cgetc
.import cursor
.include "cbm_kernal.inc"
.include "plus4.inc"
; --------------------------------------------------------------------------
.segment "LOWCODE" ; Accesses the ROM - must go into low mem
_cgetc: lda KEY_COUNT ; Get number of characters
ora FKEY_COUNT ; Or with number of function key chars
bne L2 ; Jump if there are already chars waiting
; Switch on the cursor if needed
ldy CURS_X
lda (CRAM_PTR),y ; Get current char
pha ; And save it
lda CHARCOLOR
sta (CRAM_PTR),y
lda cursor
beq L1 ; Jump if no cursor
tya
clc
adc SCREEN_PTR
sta TED_CURSLO
lda SCREEN_PTR+1
adc #$00
sbc #$0B ; + carry = $C00 (screen address)
sta TED_CURSHI
L1: lda KEY_COUNT
ora FKEY_COUNT
beq L1
pla
sta (CRAM_PTR),y
lda #$ff
sta TED_CURSLO ; Cursor off
sta TED_CURSHI
L2: sta ENABLE_ROM ; Bank in the ROM
jsr KBDREAD ; Read char and return in A (ROM routine)
sta ENABLE_RAM ; Reenable the RAM
ldx #0
rts
; --------------------------------------------------------------------------
; Make the function keys return function key codes instead of the current
; strings so the program will see and may handle them.
; Undo this change when the program ends
.constructor initkbd
.destructor donekbd
.segment "ONCE" ; Special init code segment may get overwritten
.proc initkbd
ldy #7
@L1: lda fnkeys,y
sta FKEY_SPACE+8,y
lda #$01 ; Lower 8 places are all $01
sta FKEY_SPACE,y
dey
bpl @L1
rts
.endproc
fnkeys: .byte 133, 137, 134, 138, 135, 139, 136, 140
.segment "LOWCODE" ; Accesses the ROM - must go into low mem
.proc donekbd
ldx #$39 ; Copy the original function keys
sta ENABLE_ROM ; Bank in the ROM
@L1: lda FKEY_ORIG,x
sta FKEY_SPACE,x
dex
bpl @L1
sta ENABLE_RAM ; Bank out the ROM
rts
.endproc
|
