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
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
|
;;; z80 emulator for 68k calculators
;;; Duncan Smith
;;; Project started: 2010-06-06
;;; GPL
;;; Yes, I use lots of big ascii art. With this much code, you need
;;; something to catch your eye when scrolling through it. I suppose
;;; I'll split it into different files later.
;;; Registers used:
;;;
;;; A7 = sp
;;; A6 = emulated PC XXX
;;; A5 = instruction table base pointer
;;; A4 = emulated SP XXX
;;; A3 = pointer to flag_storage
;;; A2 =
;;; A1 =
;;; A0 =
;;;
;;; D0 = current instruction, scratch for macros
;;; D1 = scratch for instructions
;;; D2 = further scratch
;;;
;;;
;;; The following have their shadows in the top half of the register
;;; D3 = AF A is in the low byte, F in the high byte (yeah ... speed)
;;; D4 = BC B high, C low
;;; D5 = DE D high, E low
;;; D6 = HL H high, L low
;;;
;;; IY is used more often so it's easier to get at. It can be slow
;;; but I don't really care to go to the effort to make it so.
;;; D7 = IX (hi), IY (low)
;;; emulated I and R are both in RAM
xdef _ti89
; xdef _ti92plus
xdef __main
xdef _tigcc_native
include "../tios.h"
include "680.inc"
__main:
movem.l d0-d7/a0-a6,-(sp)
bsr init_load
bsr display_setup
bsr emu_setup
lea emu_plain_op,a5
bsr emu_run
bsr emu_teardown
bsr display_teardown
bsr unload
movem.l (sp)+,d0-d7/a0-a6
rts
include "ports.asm"
include "interrupts.asm"
include "flags.asm"
include "alu.asm"
emu_setup:
movea.l emu_plain_op,a5
lea emu_run,a2
lea flag_storage,a3
move.w #$4000,d1
bsr deref
move.l a0,epc
move.l a0,esp
rts
emu_teardown:
rts
;; ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
;; _ __ ___ ___ _ __ ___ ___ _ __ _ _ |||||||||||||||||||||||||||
;; | '_ ` _ \ / _ \ '_ ` _ \ / _ \| '__| | | | \\\\\\\\\\\\\\\\\\\\\\\\\\\
;; | | | | | | __/ | | | | | (_) | | | |_| | |||||||||||||||||||||||||||
;; |_| |_| |_|\___|_| |_| |_|\___/|_| \__, | ///////////////////////////
;; of the virtual type |___/ |||||||||||||||||||||||||||
;; =============================================JJJJJJJJJJJJJJJJJJJJJJJJJJJ
;; Take a virtual address in d1 and dereference it. Returns the
;; host address in a0. Destroys a0, d0.
deref:
move.w d1,d0
andi.w #$3FFF,d0
movea.w d0,a0
move.w d1,d0
andi.w #$C000,d0 ; Can cut this out by pre-masking the table.
rol.w #4,d0
adda.l deref_table(pc,d0.w),a0
rts
EVEN
deref_table:
mem_page_0: dc.l 0 ; bank 0
mem_page_1: dc.l 0 ; bank 1
mem_page_2: dc.l 0 ; bank 2
mem_page_3: dc.l 0 ; bank 3
xdef mem_page_0
xdef mem_page_1
xdef mem_page_2
xdef mem_page_3
mem_page_loc_0: dc.b 0
mem_page_loc_1: dc.b 0
mem_page_loc_2: dc.b 0
mem_page_loc_3: dc.b 0
xdef mem_page_loc_0
xdef mem_page_loc_1
xdef mem_page_loc_2
xdef mem_page_loc_3
pages: dc.l 0
xdef pages
;; Take a physical address in a0 and turn it into a virtual
;; address in d0
;; Destroys d0
; XXX AFAICS, a1 is currently a scratch address register, so you can load deref_table in it, and then save some space:
; But you may wish to use it for other purposes in the future, so you needn't integrate that immediately.
underef:
lea deref_table(pc),a1
move.l a0,d0
sub.l (a1)+,d0
bmi.s underef_not0
cmpi.l #$4000,d0
bmi.s underef_thatsit
underef_not0:
move.l a0,d0
sub.l (a1)+,d0
bmi.s underef_not1
cmpi.l #$4000,d0
bmi.s underef_thatsit
underef_not1:
move.l a0,d0
sub.l (a1)+,d0
bmi.s underef_not2
cmpi.l #$4000,d0
bmi.s underef_thatsit
underef_not2:
suba.l (a1)+,a0
;; if that fails too, well shit man!
underef_thatsit:
rts
;; =========================================================================
;; instruction instruction instruction ================================
;; _ _ _ _ ================================
;; __| (_)___ _ __ __ _| |_ ___| |__ ================================
;; / _` | / __| '_ \ / _` | __/ __| '_ \ ================================
;; | (_| | \__ \ |_) | (_| | || (__| | | | ================================
;; \__,_|_|___/ .__/ \__,_|\__\___|_| |_| ================================
;; |_| =================================
;; ========== ========================================================
;; =========================================================================
include "opcodes.asm"
emu_run:
;; XXX: make this actually return
DONE
rts
emu_op_undo_cb:
emu_op_undo_dd:
emu_op_undo_ed:
emu_op_undo_fd:
rts
|
