※ 引述《pp393952 (囧?)》之銘言：
: 99 成大工科(乙) 系統程式
: 第五題..
: 題目:
: Assume that the variables f,g,h,i,and j are assigned to registers
: $s0, $s1, $s2, $s3,and $s4, respectively.
: Also, assume that the base address of integer arrays A & B are in $s6 and $s7.
: For the MIPS assembly instructions bellow, what is the corresponding
: C statment (in the simplest form)?
: (a) add $s0, $s0, $s1
: add $s0, $s3, $s2
: add $s0, $s0, $s3
: (b) addi $s6, $s6, -20
: add $s6, $s6, $s1
: lw $s0, 8($s6)
: (c) Assume that the regesters $s0, $s1, $s2, $s3 contain the values 10, 20,
: 30, and 40, respectively.
: Also, assume that register $s6 contains the value 256, and tht memory
: contains the following values:
: Address│Value
: ────┼───
: 256 │ 100
: ────┼───
: 260 │ 200
: ────┼───
: 264 │ 300
: Find the value of $s0 at the end of the assembly code in (a) and (b),
: respectively.
: 第(a)題我自己寫的答案是
: f = f + g;
: f = i + j;
^^ i+h吧？
: f = f + i;
: (b)跟(c)我就不知道怎麼翻譯...
(b) 我會寫f = A[g/4 - 3]，但真正的解答也許要用Pointer表達才會對
簡單來說前兩行是 $s6 = $s6 - 20 + $s1，其中$s6是A陣列的Base Address
然後lw $s0, 8($s6) 相當於$s0 = Memory[$s6+8]
所以最後翻譯出來會是$s0 = Memory[A的Base Address-20+$s1+8]
= Memory[A的Base Address+$s1-12]
也因為MIPS中Word Address是4的倍數，所以「也許」相當於A[g/4-3]
有沒有人有更好的寫法？
(c) 兩個答案：(a) 應該是110
(b) 根據上面，Memory[256+$s1-12] ($s1 = 20) = Memory[264]
所以是300
: 麻煩組合語言高手幫我解答一下~"~ 感謝
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