Lucent Technologies DSP1611, Information Manual, Page: 347 / 443

Information Manual DSP1611/17/18/27/28/29 DIGITAL SIGNAL PROCESSOR
April 1998 Error Correction Coprocessor (DSP1618/28 Only)
Lucent Technologies Inc.
DRAFT COPY
14-21
14.6 ECCP Instruction Timing
(continued)
14.6.3 UpdateMLSE Instruction with Hard Decision
The generic formula for the computation of the UpdateMLSE instruction cycles with hard decision (i.e., SH = 1) is
as follows:
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.
Table 14-7 shows some representative values for the UpdateMLSE
instruction cycles for different values of CL and TBLR. For the UpdateMLSE instruction, CL has a maximum value
of four corresponding to constraint length 6.
For the UpdateMLSE instruction with hard decision, the traceback length register can be programmed to a maxi-
mum value of 63.
Table 14-7. Representative UpdateMLSE Instruction Cycles (SH = 1)
CL TBLR Cycles
0 1—7 19
0 8 20
0 9 21
0 10 22
0 11 23
1 1—11 23
1 12 24
1 13 25
1 14 26
1 15 27
2 1—19 31
2 20 32
2 21 33
2 22 34
2 23 35
3 1—35 47
3 36 48
3 37 49
3 38 50
4 1—63 79
UpdateMLSE SH 1 =
( )
Cycles 15 2
CL 2 +
( )
Max 0
[
TBLR 2
CL 2 +
( )
– Max 1 2
CL 3 –
( )
,
[ ]
4 – +
( ) ]
, + + =