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1.00
CMS80F731x Reference Manual
The high 128 Bytes shown above and SFR occupy the same area (80H to FFH), but they are independent. Storage spaces
with direct addressing above 7FH (SFR) and indirect addressing above 7FH (128 Bytes high) go into different storage spaces.
The low 128Bytes spatial register allocation shown in the figure above is shown in the figure below. The lowest 32 bytes
(00H~1FH) make up 4 register groups, each group of 8 storage units, with R0~R7 as the unit number, used to save operands
and intermediate results. After reset, the 0 group is selected by default, and if a different register group is selected, it is decided
by changing the program state. The 16 Bytes (20H to 2FH) behind the register bank form a bit-addressable storage space, and
the RAM units in this area can operate either byte-byte or directly on each bit in the unit. With the remaining 80 storage units
(30H to 7FH), users can set stack areas and store intermediate data.
General Purpose Register
7FH
30H
80Bytes
2FH
20H
16Bytes
(128Bits)
Bit Addressable
1FH
18H
8Bytes
17H
10H
8Bytes
0FH
08H
8Bytes
07H
00H
8Bytes
Register Bank3
(8Bytes)
Register Bank2
(8Bytes)
Register Bank1
(8Bytes)
Register Bank0
(8Bytes)
R7
R6
R5
R4
R3
R2
R1
R0
7F
7E
7D
7C
7B
7A
79
78
77
76
75
74
73
72
71
70
6F
6E
6D
6C
6B
6A
69
68
67
66
65
64
63
62
61
60
5F
5E
5D
5C
5B
5A
59
58
57
76
55
54
53
52
51
50
4F
4E
4D
4C
4B
4A
49
48
47
46
45
44
43
42
41
40
3F
3E
3D
3C
3B
3A
39
38
37
36
35
34
33
32
31
30
2F
2E
2D
2C
2B
2A
29
28
27
26
25
24
23
22
21
20
1F
1E
1D
1C
1B
1A
19
18
17
16
15
14
13
12
11
10
0F
0E
0D
0C
0B
0A
09
08
07
06
05
04
03
02
01
00