Infineon Technologies C166S V2 User Manual page 105

I ADD R6,R0
n+2
I ADD R6,R1
n+3
I ......
n+4
.
T
n
DECODE I =
n
ADD R0,R1
ADDRESS I
n-1
MEMORY I
n-2
EXECUTE I
n-3
WRITE BACK I
n-4
Only in the case in which a GPR is updated in the ALU and then directly used in one of
the following instructions as an address pointer will the detection unit force the pipeline
to stall. None of the instructions using indirect addressing modes are capable of
using a GPR, which is to be updated by one of the two immediately preceding
instructions. The new value of the GPR is calculated in the execute stage, while the
instruction using an indirect addressing mode accesses the GPR already in the Decode
Stage. The instruction is stalled in the address stage until the operation in the ALU is
executed and the result is forwarded to the address stage.
User Manual
T T
n+1 n+2
I = I =
n+1 n+2
ADD R3,R0 ADD R6,R0
I = I =
n n+1
ADD R0,R1 ADD R3,R0
I I =
n-1 n
ADD R0,R1
I I
n-2 n-1
I I
n-3 n-2
4-105
Instruction Pipeline
T T
n+3 n+4
I = I
n+3 n+4
ADD R6,R1
I = I =
n+2 n+3
ADD R6,R0 ADD R6,R1
I = I =
n+1 n+2
ADD R3,R0 ADD R6,R0
I = I =
n n+1
ADD R0,R1 ADD R3,R0
I I =
n-1 n
ADD R0,R1
User Manual
C166S V2
T
n+5
I
n+5
I
n+4
I =
n+3
ADD R6,R1
I =
n+2
ADD R6,R0
I =
n+1
ADD R3,R0
V 1.7, 2001-01