Central Processing Unit
MPC561/MPC563 Reference Manual, Rev. 1.2
3-16
Freescale Semiconductor
illustrates the floating-point result flags that correspond to FPSCR[15:19].
3.7.4
Condition Register (CR)
The condition register (CR) is a 32-bit register that reflects the result of certain operations and provides a
mechanism for testing and branching. The bits in the CR are grouped into eight 4-bit fields: CR0 to CR7.
The CR fields can be set in the following ways:
•
Specified fields of the CR can be set by an instruction (mtcrf) to move to the CR from a GPR.
•
Specified fields of the CR can be moved from one CRx field to another with the mcrf instruction.
•
A specified field of the CR can be set by an instruction (mcrxr) to move to the CR from the XER.
•
Condition register logical instructions can be used to perform logical operations on specified bits
in the condition register.
•
CR0 can be the implicit result of an integer operation.
29
NI
Non-IEEE mode bit.
—
30–31
RN
Floating-point rounding control.
00 Round to nearest
01 Round toward zero
10 Round infinity
11 Round toward -infinity
—
Table 3-6. Floating-Point Result Flags in FPSCR
Result Flags
(Bits 15:19)
C<>=?
Result Value Class
10001
Quiet NaN
01001
– Infinity
01000
– Normalized number
11000
– Denormalized number
10010
– Zero
00010
+ Zero
10100
+ Denormalized number
00100
+ Normalized number
00101
+ Infinity
MSB
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
LSB
31
Field
CR0
CR1
CR2
CR3
CR4
CR5
CR6
CR7
Reset
Unchanged
Figure 3-7. Condition Register (CR)
Table 3-5. FPSCR Bit Descriptions (continued)
Bits
Name
Description
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...