Central Processing Unit
MPC561/MPC563 Reference Manual, Rev. 1.2
3-14
Freescale Semiconductor
A listing of FPSCR bit settings is shown in
MSB
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Field FX FEX VX
OX
UX
ZX
XX
VXSN
AN
VXISI VXIDI VXZDZ VXIMZ VXVC FR
FI
FPRF0
Reset
Unchanged
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
LSB
31
Field
FPRF[1:4]
0
VX
SOFT
VX
SQRT
VXCVI
VE
OE
UE
ZE
XE
NI
RN
Reset
Unchanged
Figure 3-6. Floating-Point Status and Control Register (FPSCR)
Table 3-5. FPSCR Bit Descriptions
Bits
Name
Description
0
FX
Floating-point exception summary. Every floating-point instruction implicitly
sets FPSCR[FX] if that instruction causes any of the floating-point exception
bits in the FPSCR to change from 0 to 1. The mcrfs instruction implicitly clears
FPSCR[FX] if the FPSCR field containing FPSCR[FX] has been copied. The
mtfsf, mtfsfi, mtfsb0, and mtfsb1 instructions can set or clear FPSCR[FX]
explicitly.
Sticky bit
1
FEX
Floating-point enabled exception summary. This bit signals the occurrence of
any of the enabled exception conditions. It is the logical OR of all the
floating-point exception bits masked with their respective enable bits. The
mcrfs instruction implicitly clears FPSCR[FEX] if the result of the logical OR
described above becomes zero. The mtfsf, mtfsfi, mtfsb0, and mtfsb1
instructions cannot set or clear FPSCR[FEX] explicitly.
Not sticky
2
VX
Floating-point invalid operation exception summary. This bit signals the
occurrence of any invalid operation exception. It is the logical OR of all of the
invalid operation exceptions. The mcrfs instruction implicitly clears
FPSCR[VX] if the result of the logical OR described above becomes zero. The
mtfsf, mtfsfi, mtfsb0, and mtfsb1 instructions cannot set or clear FPSCR[VX]
explicitly.
Not sticky
3
OX
Floating-point overflow exception.
Sticky bit
4
UX
Floating-point underflow exception.
Sticky bit
5
ZX
Floating-point zero divide exception.
Sticky bit
6
XX
Floating-point inexact exception.
Sticky bit
7
VXSNAN
Floating-point invalid operation exception for SNaN.
Sticky bit
8
VXISI
Floating-point invalid operation exception for
∞
-
∞
. Sticky
bit
9
VXIDI
Floating-point invalid operation exception for
∞
/
∞
.
Sticky bit
10
VXZDZ
Floating-point invalid operation exception for 0/0.
Sticky bit
11
VXIMZ
Floating-point invalid operation exception for
∞
x 0.
Sticky bit
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
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...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
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...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...