Motorola MPC860 PowerQUICC User Manual page 918

Part V. The Communications Processor Module
Bits Name
0 S Stop processing.
0 Do not stop after processing this FD.
1 Stop after processing this FD.
1 Ñ Reserved
2 W Wrap to the beginning of the chain. Determines the length of the FD chain.
0 Not the last FD in the chain.
1 Last FD in the chain. After this FD has been processed, the CP returns to the top of the chain
pointed to by FDBASE.
3 I Interrupt the core.
0 No interrupt is generated after this function is processed.
1 A maskable interrupt is generated after this function is processed.
4 X Complex number option. Used to specify a real/complex output, or a real/complex scalar for LMS.
0 Use only the real component.
1 Use both the real and imaginary components.
5 IALL Auto-increment X for all iterations.
0 X (input) data pointer is incremented (Modulo M+1) by the number of samples speciÞed in
FD[INDEX] after the last iteration.
1 X (input) data pointer is incremented (Modulo M+1) by the number of samples speciÞed in
FD[INDEX] after each iteration.
6Ð7 INDEX Auto-increment index.
00 X (input) pointer is not incremented.
01 X (input) pointer is incremented by one sample.
10 X (input) pointer is incremented by two samples.
11 X (input) pointer is incremented by three samples.
8 PC Preset coefÞcients pointer.
0 CoefÞcients pointer is not preset after each iteration.
1 CoefÞcients pointer is preset to CBASE after each iteration.
11Ð15 OPCODE Function operation code. SpeciÞes the function to be executed. See Table 36-1 above.
36.4 Data Representation
The inputs, coefÞcients and outputs are represented by 16-bit, Þxed-point,
twoÕs-complement numbers. Figure 36-4 shows the real number representation.
Bit 0 1
Field S
A complex number is represented by a pair of 16-bit componentsÑ16 bits for the
imaginary component and 16 bits for the realÑas shown in Figure 36-5.
36-4
Table 36-2. FD Status and Control Bits
2 3 4 5 6
Figure 36-4 . Real Number Representation
MPC860 PowerQUICC UserÕs Manual
Description
7 8 9 10 11
Real
12 13 14 15
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