CL-PS7500FE 查看數據表（PDF） - Cirrus Logic
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CL-PS7500FE Datasheet PDF : 251 Pages
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CL-PS7500FE
System-on-a-Chip for Internet Appliance
WFS,RFS,WFC, and RFC
efgh
these bits are reserved and should be zero.
Constants
Constants cannot be specified in the Fm field for the FIX instruction, as there is no point FIXing a known
value into an ARM integer register; it would be quicker to use a MOV instruction.
19.3.1 Compare Operations
31
28 27
24 23 22 21 20 19
16 15
12 11
87
43
0
cond
1110
abc
1
e Fn
1111
0001
fgh1
i Fm
NOTE: These are special cases of the general CPRT instruction, with Rd = 15 and L/S = 1.
<CMF|CNF|CMFE|CNFE>{cond} Fn, Fm
abc
operation
i
constant ROM/Fm (see Section 19.2)
efgh
are reserved and should be ‘0’
abc Mnemonic Description
100 CMF
Compare floating
101 CNF
Compare negated floating
110 CMFE
Compare floating with exception
111 CNFE
Compare negated floating with exception
Operation
compare Fn with Fm
compare Fn with -Fm
compare Fn with Fm
compare Fn with -Fm
Compares
Compares are provided with and without the exception that could arise if the numbers are unordered.
When testing IEEE predicates, the CMF instruction should be used to test for equality (that is, when a
BEQ or BNE is used afterwards) or to test for unorderedness (in the V flag). The CMFE instruction should
be used for all other tests (BGT, BGE, BLT, and BLE afterwards). CMFE produces an exception if the num-
bers are unordered (whenever at least one operand is a NaN). CMF only produces an exception when at
least one operand is a signalling NaN.
The ARM flags N, Z, C, and V refer to Table 19-4 after compares.
Table 19-4. Flag Settings When the AC Bit in the FPSR is Clear
Flag
N
Z
C
V
Description
Example
Less Than
Fn less than Fm (or -Fm)
Equal
Greater Than or Equal Fn greater than or equal to Fm
Unordered
NOTE: That when two numbers are not equal N and C are not necessarily opposites: if the result is unordered they
are both false.
June 1997
ADVANCE DATA BOOK v2.0
FLOATING-POINT INSTRUCTION SET
179
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