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comparison simple_console.txt @ 0:7e44f7d5810b

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Initial commit. CPU working well enough for simple hello world program.
author Michael Pavone <pavone@retrodev.com>
date Tue, 22 Mar 2016 22:44:02 -0700
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children 6204c81e2933
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-1:000000000000 0:7e44f7d5810b
1 Key:
2 1 = literal 1 bit
3 0 = literal 0 bit
4 O = opcode bit
5 D = destination register bit
6 A = source A register bit
7 B = source B register bit
8
9 DDDD AAAA BBBB OOOO
10
11 0: ldim
12 D = destination reg
13 A and B form 8-bit immediate value
14 1: ldimh
15 D = destination reg
16 A and B form 8-bit immediate value
17 2: ld8
18 3: ld16
19 4: str8
20 5: str16
21 6: add
22 7: adc
23 8: and
24 9: or
25 A: xor
26 B: lsl
27 C: lsr
28 D: asr
29 E: bcc
30 F: single source
31
32
33
34 DDDD AAAA OOOO 1111
35
36 single source
37
38 0: mov
39 1: neg
40 2: not
41 3: cmp
42 4: call
43 A = register containing pointer to function
44 D = register that will store PC value
45 5: swap
46 6: in
47 7: out
48 8: ini
49 9: outi
50 A: addi
51 B: andi
52 C: ori
53 D: ls[lr]i
54 MSB of AAAA determines direction
55 LS 3 bits determines magnitude
56 E: asri
57 F: single reg
58
59
60 DDDD OOOO 1111 1111
61
62 0: reti - return from interrupt, D = register to restore from uer
63 1: trap
64 2: trapi
65 3: getepc
66 4: setepc
67 5: getesr
68 6: setesr
69 7: getenum
70 8: setenum
71 9: getuer
72 A: setuer
73 B: getenum
74 C: setenum
75 E: invalid
76 F: invalid
77
78
79 Registers:
80
81 r0 - r12 : general purpose
82 r13 : technically general purpose, but canonically the stack register
83 r14 : PC
84 r15 : status register
85
86 IO: Ports
87
88 0: Controller 1
89 1: Controller 2
90 2: Controller 3
91 3: Controller 4
92
93 4: Channel A Freq
94 Load value for a 16-bit down-counter
95 Polarity of output is switched on transition from 1 to 0
96 Value is loaded on cycles where counter is 0
97 Special case value of 0 in this register forces polarity to positive
98 5: Channel B Freq
99 6: Channel C Freq
100 7: Channel D Freq
101
102 8: Channel A/B Vol
103 9: Channel C/D Vol
104
105 A: Timer Freq
106 B: "Serial" Debug Port
107
108 D: Write Pallette Address : Read Vertical Position
109 E: Write Name Table Address : Read Horizontal Position
110 F: Write Sprite Table Address : Read Status?
111
112
113
114
115