IO3¶

Pipeline Structure¶

Pasted image 20221021064643.png

Issue Queue¶

Opc	Imm	S	V	Dest	V	P	Src0	V	P	Src1

P - Pending
S - Speculative
V - Valid (needs to be checked for availability)
P - Pending (for operands to be producted)

Instruction is ready when \((!V_{src0}\ ||\ !P_{src0}) \ \&\& \ (!V_{src1}\ || \ !P_{src1})\)

0 MUL R1, R2, R3   F   D   I   Y0  Y1  Y2  Y3  W 
1 ADDIU R11,R10,1      F   D   I   X0  W 
2 MUL R5, R1, R4           F   D   i       I   Y0  Y1  Y2  Y3  W 
3 MUL R7, R5, R6               F   D   i                   I   Y0 Y1 Y2 Y3 W 
4 ADDIU R12,R11,1                  F   D   i   I   X0  W 
5 ADDIU R13,R12,1                      F   D   i   I   X0  W 
6 ADDIU R14,R12,2                          F   D   i   I   X0  W

Two instructions can't be issued simultaneously (structural hazard)