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Number Representation and Arithmetic

GATE CSE 2025 Set 2 · Q49

MSQ2 marksMedium

Time

Three floating point numbers X,Y,X, Y, and ZZ are stored in three registers Rx,RY,\text{Rx}, \text{R}_Y, and RZ\text{R}_Z, respectively in IEEE 754 single precision format as given below in hexadecimal: Rx=0xC1100000,RY=0x40C00000,\text{Rx} = \text{0xC1100000}, \text{R}_Y = \text{0x40C00000}, and RZ=0x41400000\text{R}_Z = \text{0x41400000} Which of the following option(s) is/are CORRECT?

Select all that applyOne or more correct

Pick every correct option

Solution

Step-by-step verified solution

Official answer: A) 4(X + Y) + Z = 0; B) 2Y - Z = 0; C) 4X + 3Z = 0

Number Representation and Arithmetic

In IEEE 754 single-precision floating-point format (32-bit):

  • Sign bit (SS): 1 bit

  • Biased exponent (EE): 8 bits (bias = 127)

  • Fraction / Mantissa (MM): 23 bits with an implicit leading 1.

The real value is given by (−1)S×(1.M)2×2E−127(-1)^S \times (1.M)_2 \times 2^{E - 127}.

  1. For register Rx=0xC1100000\text{Rx} = \text{0xC1100000}:

    • Binary: 1 10000010 00100000000000000000000

    • S=1S = 1

    • E=100000102=130  ⟹  Actual exponent=130−127=3E = 10000010_2 = 130 \implies \text{Actual exponent} = 130 - 127 = 3

    • Mantissa =1.0012=1+18=1.125=98= 1.001_2 = 1 + \frac{1}{8} = 1.125 = \frac{9}{8}

    • X=−1×98×23=−9.0X = -1 \times \frac{9}{8} \times 2^3 = -9.0

  2. For register RY=0x40C00000\text{R}_Y = \text{0x40C00000}:

    • Binary: 0 10000001 10000000000000000000000

    • S=0S = 0

    • E=100000012=129  ⟹  Actual exponent=129−127=2E = 10000001_2 = 129 \implies \text{Actual exponent} = 129 - 127 = 2

    • Mantissa =1.12=1.5=32= 1.1_2 = 1.5 = \frac{3}{2}

    • Y=+1×1.5×22=6.0Y = +1 \times 1.5 \times 2^2 = 6.0

  3. For register RZ=0x41400000\text{R}_Z = \text{0x41400000}:

    • Binary: 0 10000010 10000000000000000000000

    • S=0S = 0

    • E=100000102=130  ⟹  Actual exponent=130−127=3E = 10000010_2 = 130 \implies \text{Actual exponent} = 130 - 127 = 3

    • Mantissa =1.12=1.5=32= 1.1_2 = 1.5 = \frac{3}{2}

    • Z=+1×1.5×23=12.0Z = +1 \times 1.5 \times 2^3 = 12.0

Now evaluate each option:

  • (A) 4(X+Y)+Z=4(−9+6)+12=4(−3)+12=−12+12=04(X + Y) + Z = 4(-9 + 6) + 12 = 4(-3) + 12 = -12 + 12 = 0 (Correct)

  • (B) 2Y−Z=2(6)−12=12−12=02Y - Z = 2(6) - 12 = 12 - 12 = 0 (Correct)

  • (C) 4X+3Z=4(−9)+3(12)=−36+36=04X + 3Z = 4(-9) + 3(12) = -36 + 36 = 0 (Correct)

  • (D) X+Y+Z=−9+6+12=9≠0X + Y + Z = -9 + 6 + 12 = 9 \neq 0 (Incorrect)

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This Number Representation and Arithmetic previous year question is Q49 of the GATE CSE 2025 Set 2 paper. Find more GATE CSE PYQs on Number Representation and Arithmetic in Digital Logic, or browse all GATE CSE PYQs.

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Number Representation and Arithmetic in GATE CSE

Number Representation and Arithmetic has 33 GATE CSE PYQs across 20 papers from 2012 to 2026. 2 of them are 2-mark MSQs like this one, and it is the only one in GATE CSE 2025 Set 2.

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GateAI solution cardGATE CSE 2025 Set 2 · Q49 · MSQ

Three floating point numbers X, Y, and Z are stored in three registers Rx, RY, and RZ, respectively in IEEE 754 single precision format as given below in hexadecimal: Rx = 0xC1100000, RY = 0x40C00000, and RZ = 0x41400000 Which of the following option(s) is/are CORRECT?

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