Double-Precision Floating-Point Multiply
MPYDP
4-55
TMS320C67x Floating-Point Instruction Set
Pipeline
Stage
E1
E2
E3
E4
E5
E6
E7
E8
E9
E10
Read
src1_l
src2_l
src1_l
src2_h
src1_h
src2_l
src1_h
src2_h
Written
dst_l
dst_h
Unit in use
.M
.M
.M
.M
If
dst is used as the source for the ADDDP, CMPEQDP, CMPLTDP,
CMPGTDP, MPYDP, or SUBDP instruction, the number of delay slots can be
reduced by one, because these instructions read the lower word of the DP
source one cycle before the upper word of the DP source.
Instruction Type
MPYDP
Delay Slots
9
Functional Unit
Latency
4
Example
MPYDP .M1
A1:A0,A3:A2,A5:A4
Before instruction
10 cycles after instruction
A1:A0
4021 3333h
3333 3333h
8.6
A1:A0
4021 3333h
4021 3333h
8.6
A3:A2
C004 0000h
0000 0000
–2.5
A3:A2
C004 0000h
0000 0000h
–2.5
A5:A4
XXXX XXXXh
XXXX XXXXh
A5:A4
C035 8000h
0000 0000h
–21.5
Pipeline