Avoiding Stalls
Finding the best ordering of instructions to minimize (or avoid) stalls is a scheduling problem
LD(r31, X, r1)
LD(r31, Y, r2)
ADD(r1, r2, r3)
SUB(r1, r2, r4)
MUL(r3, r4, r5)
ST(r5, P, r31)
LD(r31, Z, r6)
LD(r31, W, r7)
SUB(r6, r7, r8)
ST(r8, Q, r31)
ADD(r5, r8, r9)
ST(r9, T, r31)
Average CPI =
Average CPI =
Stalls
LD(r31, X, r1)
LD(r31, Y, r2)
LD(r31, Z, r6)
LD(r31, W, r7)
ADD(r1, r2, r3)
SUB(r1, r2, r4)
MUL(r3, r4, r5)
SUB(r6, r7, r8)
ST(r5, P, r31)
ADD(r5, r8, r9)
ST(r8, Q, r31)
ST(r9, T, r31)
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