Pipeline Execution of Instruction Types

4.2.9DP Compare Instructions

The DP compare instructions use the E1 and E2 phases of the pipeline to complete their operations (see Table 4−11). The lower 32 bits of the sources are read on E1, the upper 32 bits of the sources are read on E2, and the results are written on E2. The following instructions are DP compare instructions:

-CMPEQDP

-CMPLTDP

-CMPGTDP

The DP compare instructions are executed on the .S unit. The functional unit latency for DP compare instructions is 2. The status is written to the FAUCR on E2. Figure 4−21 shows the fetch, decode, and execute phases of the pipe- line that the DP compare instruction uses.

Table 4−11. DP Compare Instruction Execution

Pipeline Stage

E1

E2

 

 

 

Read

src1_l

src1_h

 

src2_l

src2_h

Written

 

dst

Unit in use

.S

.S

 

 

 

Figure 4−21. DP Compare Instruction Phases

PG PS PW PR DP DC E1 E2

1 delay slot

SPRU733

Pipeline

4-27

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Image 359
Texas Instruments TMS320C67X/C67X+ DSP manual DP Compare Instructions, 11. DP Compare Instruction Execution