Binary Conversions
1. **Problem:** Convert 13₁₀ to 8-bit binary.
2. **Formula/Method:** Use powers of two from $2^7$ to $2^0$ and find which powers sum to 13.
3. **Work:**
- Powers: 128, 64, 32, 16, 8, 4, 2, 1
- 13 - 8 = 5 (bit for $2^3$ is 1)
- 5 - 4 = 1 (bit for $2^2$ is 1)
- 1 < 2 (bit for $2^1$ is 0)
- 1 - 1 = 0 (bit for $2^0$ is 1)
4. **Binary bits:** 00001101
5. **Answer:** $13_{10} = 00001101_2$
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1. **Problem:** Represent $-75_{10}$ in 16-bit two's complement.
2. **Method:** Convert +75 to binary, invert bits, add 1.
3. **Work:**
- +75 in binary (8-bit): 01001011
- Pad to 16-bit: 0000000001001011
- Invert bits: 1111111110110100
- Add 1: 1111111110110101
4. **Answer:** $-75_{10} = 1111111110110101_2$
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1. **Problem:** Convert $1110110101011001_2$ to hexadecimal.
2. **Method:** Group bits in 4s from right: 1110 1101 0101 1001
3. **Work:**
- 1110 = E
- 1101 = D
- 0101 = 5
- 1001 = 9
4. **Answer:** $1110110101011001_2 = ED59_{16}$
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1. **Problem:** Convert "Welcome to COSC204!" to 8-bit ASCII binary.
2. **Method:** Use ASCII decimal codes, convert each to 8-bit binary.
3. **Work:**
- W=87=01010111
- e=101=01100101
- l=108=01101100
- c=99=01100011
- o=111=01101111
- m=109=01101101
- e=101=01100101
- space=32=00100000
- t=116=01110100
- o=111=01101111
- space=00100000
- C=67=01000011
- O=79=01001111
- S=83=01010011
- C=67=01000011
- 2=50=00110010
- 0=48=00110000
- 4=52=00110100
- !=33=00100001
4. **Answer:** Concatenated binary string as above.
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1. **Problem:** Signed 16-bit binary representation.
2. **a) 3046₁₀:**
- Divide by 16: 3046 ÷ 16 = 190 r6 (6)
- 190 ÷ 16 = 11 r14 (E)
- 11 ÷ 16 = 0 r11 (B)
- Hex: 0x0BE6
- Binary: 0000101111100110
3. **b) -2078₁₀:**
- +2078 hex: 0x081E
- Binary: 0000100000011110
- Invert: 1111011111100001
- Add 1: 1111011111100010
4. **c) -CC₁₆:**
- CC hex = 0x00CC = 0000000011001100
- Invert: 1111111100110011
- Add 1: 1111111100110100
5. **d) 204₁₆:**
- 0x0204 = 0000001000000100
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1. **Problem:** Compute $x - y$ by $x + (-y)$ in 16-bit binary.
2. **a) 3046 - 2078:**
- 3046 = 0x0BE6 = 0000101111100110
- -2078 = 0xF7E2 = 1111011111100010
- Add: 0x0BE6 + 0xF7E2 = 0x03C8
- Decimal check: 3046 - 2078 = 968
- Binary: 0000001111001000
3. **b) 204₁₆ - CC₁₆:**
- 204₁₆ = 0x0204 = 516 decimal
- CC₁₆ = 0x00CC = 204 decimal
- Two's complement of CC: 0xFF34
- Add: 0x0204 + 0xFF34 = 0x0138
- Decimal: 312
- Binary: 0000000100111000
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1. **Problem:** Truth tables for boolean functions.
2. **a) MUX(A,B,C) = (¬A ∧ B) ∨ (A ∧ C):**
| A | B | C | ¬A | ¬A∧B | A∧C | MUX |
|---|---|---|----|-------|-----|-----|
| F | F | F | T | F | F | F |
| F | F | T | T | F | F | F |
| F | T | F | T | T | F | T |
| F | T | T | T | T | F | T |
| T | F | F | F | F | F | F |
| T | F | T | F | F | T | T |
| T | T | F | F | F | F | F |
| T | T | T | F | F | T | T |
3. **b) XOR(A,B) = (A ∨ B) ∧ ¬(A ∧ B):**
| A | B | A∨B | A∧B | ¬(A∧B) | XOR |
|---|---|-----|-----|--------|-----|
| F | F | F | F | T | F |
| F | T | T | F | T | T |
| T | F | T | F | T | T |
| T | T | T | T | F | F |
4. **c) EQV(A,B) = (A ∧ B) ∨ (¬A ∧ ¬B):**
| A | B | A∧B | ¬A | ¬B | ¬A∧¬B | EQV |
|---|---|-----|----|----|-------|-----|
| F | F | F | T | T | T | T |
| F | T | F | T | F | F | F |
| T | F | F | F | T | F | F |
| T | T | T | F | F | F | T |
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1. **Problem:** Evaluate specific cases from tables.
2. **Answers:**
- MUX(T,F,T) = T
- XOR(F,F) = F
- EQV(T,F) = F
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1. **Problem:** Little-endian byte order for 32-bit value $90AB12CD_{16}$ at address $4000_{16}$.
2. **Method:** Store least significant byte at lowest address.
3. **Work:**
- Bytes: 90 AB 12 CD
- Little-endian order: CD (4000), 12 (4001), AB (4002), 90 (4003)
4. **Answer:** Byte at address 4002 = AB
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1. **Problem:** Memory dump at 5000₁₆; little-endian 32-bit integers.
2. **Given bytes:**
- 5000: 78
- 5001: 56
- 5002: 34
- 5003: 12
- 5004: FE
- 5005: DC
- 5006: BA
- 5007: 98
3. **Work:**
- First integer: 0x12345678 = 305419896 decimal
- Second integer: 0x98BADCFE = 2562383102 decimal (unsigned)
4. **Answer:**
- First integer = 0x12345678 (305419896 decimal)
- Second integer = 0x98BADCFE (2562383102 decimal unsigned)