Central Processing Unit
MPC561/MPC563 Reference Manual, Rev. 1.2
3-26
Freescale Semiconductor
3.9.10.2
Floating-Point Exception Cause Register (FPECR)
The FPECR, SPR 1022, is a supervisor-level internal status and control register used by the user’s
floating-point assist software envelope. It contains four status bits that indicate whether the result of the
operation is tiny and whether any of three source operands are denormalized. In addition, it contains one
control bit to enable or disable SIE mode. This register must not be accessed by user code.
A listing of FPECR bit settings is shown in
NOTE
Software must insert a sync instruction before reading the FPECR.
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Field SIE
—
SRESET
0000_0000_0000_0000
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LSB
31
Field
—
DNC DNB DNA
TR
SRESET
0000_0000_0000_0000
Addr
SPR 1022
Figure 3-18. Floating-Point Exception Cause Register (FPECR)
Table 3-16. FPECR Bit Descriptions
Bits
Name
Description
0
SIE
Synchronized ignore exception 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
Summary of Contents for MPC561
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Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
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Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
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