MPC555
/
MPC556
CENTRAL PROCESSING UNIT
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
3-27
A listing of FPECR bit descriptions is shown in
NOTE
Software must insert a
sync
instruction before reading the FPECR.
3.9.10.3 Additional Implementation-Specific Registers
Refer to the following sections for details on additional implementation-specific regis-
ters in the MPC555 / MPC556:
•
4.6 Burst Buffer Programming Model
•
6.13.1.2 Internal Memory Map Register
•
•
SECTION 21 DEVELOPMENT SUPPORT
FPECR —
Floating-Point Exception Cause Register
SPR 1022
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
SIE
RESERVED
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LSB
31
RESERVED
DNC
DNB
DNA
TR
RESET:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Table 3-18 FPECR Bit Descriptions
Bit(s)
Name
Description
0
SIE
SIE mode control bit
0 = Disable SIE mode
1 = Enable SIE mode
[1:27]
—
Reserved
28
DNC
Source operand C denormalized status bit
0 = Source operand C is not denormalized
1 = Source operand C is denormalized
29
DNB
Source operand B denormalized status bit
0 = Source operand B is not denormalized
1 = Source operand B is denormalized
30
DNA
Source operand A denormalized status bit
0 = Source operand A is not denormalized
1 = Source operand A is denormalized
31
TR
Floating-point tiny result
0 = Floating-point result is not tiny
1 = Floating-point result is tiny
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