Motorola DSP96002 User Manual
Page 192
A - 4
DSP96002 USER’S MANUAL
MOTOROLA
compare instruction. The
–
R bit is cleared during processor reset. See the example for
the FCMPG instruction for additional information.
A(Accept)
The A bit is only affected by the compare instructions CMP, CMPG, FCMP and FCMPG.
The A bit is calculated based on its previous value and the results of the current compare
instruction. The A bit is cleared during processor reset. See the example for the FCMPG
instruction for additional information.
There are 16 theoretical combinations of N, Z, I and NAN for floating point results, but only eight combina-
tions are possible in practice due to the exclusive nature of the data types described by the condition
codes. The eight possible combinations are shown in Figure A-3.
Figure A-4 details how each instruction affects the condition codes. Figure A-4 gives the chip implemen-
tation viewpoint while the opcode descriptions in Section A-3 give the user viewpoint. For example, the Z
bit computation for the CLR instruction is shown in the figure as the standard definition while the opcode
description indicates that Z is always set.
N
Z
I
NAN
Result Data Type
0
0
0
0
+Normalized/Denormalized
1
0
0
0
- Normalized/Denormalized
0
1
0
0
+0
1
1
0
0
-0
0
0
1
0
+Infinity
1
0
1
0
-Infinity
0
0
0
1
+NaN
1
0
0
1
-
NaN
Figure A-3.
Possible Combinations of the N, Z, I and NAN Bits for Floating-Point Results