1. 1 Bit Operator

2. Advanced Compiler Laboratory2 Bit operators ! : invert logical value if value is 0 change to 1, otherwise set to 0 ~ : invert all bits ~0x1010 = 0xefef & : bits ‘and’ operator and | : ‘or’ operator or

3. Advanced Compiler Laboratory3 Bit operators ^ : ‘xor’ operator xor + : add << : left bit shifter >> : right bit shifter warning: it is arithmetic operator( if MSB is 1, go on filling 1 to MSB )

4. Advanced Compiler Laboratory4 Our program restrictions We are only allowed to use the following eight operations( or more fewer op. depending each problem ) ! ~ & ^ | + > any constants longer than 8bits is not allowed max constant is 0xff

5. Advanced Compiler Laboratory5 file download wget http://aces.snu.ac.kr/~jongyoung/lect ure/pa01.tar http://aces.snu.ac.kr/~jongyoung/lect ure/pa01.tar tar -xvf pa01.tar We modify only bits.c dlc check our program whether coding rule is correct btest check our ‘bits.c’ correctness

6. Advanced Compiler Laboratory6 Goal Modify functions in bits.c to same result what we expected.

7. Advanced Compiler Laboratory7 bitAnd Using de morgan’s law ~(A and B) = ~A or ~B Only use the operation ~ and |

8. Advanced Compiler Laboratory8 bitXor Using only the operation & and ~ Similar as bitAnd

9. Advanced Compiler Laboratory9 evenBits Return a word with all even-numbered bits set to 1 Sequence add and bit-shift for some constant. Careful for constant’s length

10. Advanced Compiler Laboratory10 bitMask First, make 32bit constant that all bits are ‘1’ properly shift If lowbit >= highbit, then the mask should be all 0’s bitMask(5,3) returns 0x38

11. Advanced Compiler Laboratory11 bitParity Reduce problem’s complexity by folding input variable Return 1 if x contains an odd number of 0’s. bitParity(5) = 0, bitParity(7) = 1

12. Advanced Compiler Laboratory12 fitsBit Divide input into positive and negative. Return 1 if x can be represented as an n-bit, two’s complement integer, where 1 <= n <= 32. fitsBit(5,3) returns 0 fitsBit(-4,3) returns 1

13. Advanced Compiler Laboratory13 sm2tc Convert from sign-magnitude to two’s complement where the MSB is the sign bit Extract sign bit and others Sm2tc(0x80000005) returns -5

14. Advanced Compiler Laboratory14 Restriction

15. Advanced Compiler Laboratory15 Function Description

16. Advanced Compiler Laboratory16 Function Description