推 s90413k64:1G*(10-9)/(4-1-1) 08/06 23:06
懂了!
※ 編輯: mqazz1 來自: 192.192.13.101 (08/07 14:22)
→ cola1230:懂了! 趕快寫下來 08/07 18:05
consider program P, which runs on a 1GHz machine M in 10 seconds. An
optimization is made to P, replacing all instances of multiplying a value by 4
(mult X, X, 4) with two instructions that set x to x+x twice (add X,X; and X,X)
Call this new optimized program P'. The CPI of a multiply instruction is 4,
and the CPI of an add is 1. After recompiling, the program now runs in 9
seconds on machine M. How many multiplies were replaced by the new compiler?
張凡上冊248頁 張凡答案給5 * 10^8 請問這題要怎麼解?
謝謝
--
※ 發信站: 批踢踢實業坊(ptt.cc)
◆ From: 218.166.113.236