COMP1521 2022T3 Q5 · 位运算(MIPS)

COMP1521 2022T3 Q5 · 10 marks · MIPS
知识点: 位运算(MIPS)（BIT） · 次: 循环/最长游程 · 难度: 中等
Topic: Bitwise / data representation · Source: https://cgi.cse.unsw.edu.au/~cs1521/26T1/resources/practice_exams.html

一句话 / Summary: Q4的MIPS版本

You have been given 22t3final_q5.s , a MIPS assembler program that
reads an integer and then prints 42.

Add code to 22t3final_q5.s so that it returns
the length of the longest sequence of consecutive bits set to 1
in the supplied 32 bit integer.

In other words, it should behave the same as the previous question.

mipsy input is signed, so it won't accept some of the input we used in the last question.
For example, mipsy won't accept as 4294967295 as input.
We can get the same bit pattern (0xFFFFFFFF) by using -1 as input.
This doesn't affect the code you need to write.

For example:

305419896 == 0x12345678
1521 mipsy 22t3final_q5.s
305419896
4
0 == 0x00000000
1521 mipsy 22t3final_q5.s
0
0
4 == 0x00000004
1521 mipsy 22t3final_q5.s
4
1
15 == 0x0000000F
1521 mipsy 22t3final_q5.s
15
4
-1 == 0xFFFFFFFF
1521 mipsy 22t3final_q5.s
-1
32
-1431655766 == 0xAAAAAAAA
1521 mipsy 22t3final_q5.s
-1431655766
1
268566401 == 0x1001FF81
1521 mipsy 22t3final_q5.s
268566401
10

Your program can assume its input only contains only 1 integer.

Your program can assume that the integer will fit in a MIPS register .

Your program can assume that MIPS will accept the integer as valid input.

Your solution must be in MIPS only.

Your solution must not be in C , C++ , Python , or any other language.

No error checking is necessary or required.

🤖 Write MIPS (mipsy). Read one integer; print the length of the longest run of consecutive 1-bits in its 32-bit representation.

Verified on the sandbox AND cross-checked against an independent oracle (official examples included).