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10 adddp/subdp instructions – Texas Instruments TMS320C67X/C67X+ DSP User Manual

Page 360

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Pipeline Execution of Instruction Types

Pipeline

4-28

SPRU733

4.2.10 ADDDP/SUBDP Instructions

The ADDDP/SUBDP instructions use the E1 through E7 phases of the pipeline
to complete their operations (see Table 4−12). The lower 32 bits of the result
are written on E6, and the upper 32 bits of the result are written on E7. The
ADDDP/SUBDP instructions are executed on the .L unit. The functional unit
latency for ADDDP/SUBDP instructions is 2. The status is written to the
FADCR on E6. Figure 4−22 shows the fetch, decode, and execute phases of
the pipeline that the ADDDP/SUBDP instructions use.

Table 4−12. ADDDP/SUBDP Instruction Execution

Pipeline Stage

E1

E2

E3

E4

E5

E6

E7

Read

src1_l
src2_l

src1_h
src2_h

Written

dst_l

dst_h

Unit in use

.L or .S

.L or .S

Figure 4−22. ADDDP/SUBDP Instruction Phases

PG

PS

PW

PR

DP

DC

E1

E2

E3

E4

E5

E6

E7

6 delay slots