Show the hex representation of MIPS instructions

shieldcy

Hey all
1. The problem statement, all variables and given/known data
Here i want to translate them and show the hex representation of these instructions:
1)add $t0, $t0, $zero
2)lw $t2, 16($s3)

2. Relevant equations
3. The attempt at a solution
eg. 2)
lw | $s3 | $t2 | 16
I-TYPE

then translate the assembly code:
35 | 19 | 10 | 16

The solution is 0x8E6A0010
But i 've no idea how the answer has been reached... Any help?
Thank's a lot

tedbradly

What is the context of this question? Should you be able to answer it on a test or is it a homework problem meant to familiarize you with your assembler? I would write the code, compile it, and view the answer by stepping through the code.

shieldcy

It's an exam type question but MIPS assembly language table (http://en.wikipedia.org/wiki/MIPS_ar...embly_language) will be provided in exams

lewando

Looks like you have decomposed the assembly instruction correctly:

35₁₀ = instruction
19₁₀ = s
10₁₀ = t
16₁₀ = C

Convert the base-10 values that you obtained into binary. Then group your binary results into the following I-type format:
[iiiiiiss] [sssttttt] [CCCCCCCC] [CCCCCCCC]

(use 6-bits of your instruction result, 5-bits of s, 5 of t, 16 bits of C, zero-padding as needed)

Then convert each 8-bit group to its hexadecimal equivalent.

shieldcy

thank you so much! cheers ;)

shieldcy

Could you please show me the way to convert hex value 0x8E6A0010 to decimal?

tedbradly

The nth digit corresponds to how many b^n's there are, starting at n = 0, where b is the base (16 here).

0*16^0 + 1*16^1 + 0*16^2 + ... + 8*16^7

shieldcy

Oo yeah... thank's man ;)

tedbradly

No problem. That method works for converting any integer of any base into base 10 (you can even convert base 10 into base 10 with it).

e.g.
10110 base 2 = 0*2^0 + 1*2^1 + 1*2^2 + 0*2^3 + 1*2^4 = 2 + 4 + 16 = 22