Information Manual
DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998
Error Correction Coprocessor (DSP1618/28 Only)
Lucent Technologies Inc.
DRAFT COPY
14-23
(continued)
14.6.5 UpdateConv Instruction with Hard Decision
With the ECON.SH field set to 1 (i.e., with hard decision mode selected), the following formula yields the number of
instruction cycles for the UpdateConv instruction:
where CL represents the value of the constraint length field in the ECON register and TBLR is the traceback length
value programmed into the TBLR register.
shows some representative values for the UpdateConv
instruction cycles with hard decision mode selected for different values of CL and TBLR.
The traceback length register can reach a maximum value of 63 with the hard decision decoding mode selected.
14.6.6 TraceBack Instruction
The length of the TraceBack instruction is only a function of the programmed traceback length and is equal to:
The TBLR can be programmed to a maximum value of 31 if the TraceBack instruction is used after UpdateMLSE
instructions or after UpdateConv instructions with soft decision symbols. A maximum value of 63 can be pro-
grammed for hard decision decoding after UpdateMLSE or UpdateConv instructions. The contents of the TBLR
register are autodecremented after the TraceBack instruction is completed.
Table 14-9. Representative UpdateConv Instruction Cycles (SH = 1)
CL
TBLR
Cycles
0
1—6
18
0
7
19
0
8
20
0
9
21
0
10
22
1
1—10
22
1
11
23
1
12
24
1
13
25
1
14
26
2
1—18
30
2
19
31
2
20
32
2
21
33
2
22
34
3
1—34
46
3
35
47
3
36
48
3
37
49
3
38
50
4
1—63
78
5
1—63
142
UpdateConv SH
1
=
(
)
Cycles
14
2
CL
2
+
(
)
Max 0
[
TBLR
2
CL
2
+
(
)
–
Max 1 2
CL
3
–
(
)
,
[
]
3
–
+
(
)]
,
+
+
=
TraceBack Cycles
TBLR
14
+
=
Содержание DSP1611
Страница 18: ...Chapter 1 Introduction...
Страница 27: ...Chapter 2 Hardware Architecture...
Страница 52: ...Chapter 3 Software Architecture...
Страница 116: ...Chapter 4 Instruction Set...
Страница 154: ...Chapter 5 Core Architecture...
Страница 176: ...Chapter 6 External Memory Interface...
Страница 208: ...Chapter 7 Serial I O...
Страница 237: ...Chapter 8 Parallel I O DSP1617 Only...
Страница 261: ...Chapter 9 Parallel Host Interface PHIF DSP1611 18 27 28 29 Only...
Страница 275: ...Chapter 10 Bit I O Unit...
Страница 284: ...Chapter 11 JTAG Test Access Port...
Страница 306: ...Chapter 12 Timer...
Страница 313: ...Chapter 13 Bit Manipulation Unit...
Страница 325: ...Chapter 14 Error Correction Coprocessor DSP1618 28 Only...
Страница 350: ...Chapter 15 Interface Guide...
Страница 367: ...Appendix A Instruction Encoding...
Страница 379: ...Appendix B Instruction Set Summary...
Страница 381: ...aD extractz aS IM16 B 52 aD insert aS arM B 53 aD insert aS IM16 B 54 aD aS aaT B 55...
Страница 437: ...Index...