ICS 51 - Introductory Computer Organization

1. ICS 51 - Introductory Computer Organization Review

2. Registers

3. Instructions • Data movement instructions • Mov • Arithmetic operations • Add, Sub, Mul, Div • Logical operations • And, Or, Not, Xor, Shr, Shl • Comparison instructions • Cmp • Control Transfer Instructions • Unconditional: Jmp • Conditional: Jg, Jl, Jge, Jle, Jne

4. Data Ranges and Data Types • Data Ranges • E.g. 4 bits: • Unsigned: from 0 to 15 • 1’s complement: from -7 to 7 • 2’s complement: from -8 to 7 • Data Types • Byte: 8 bits • Word: 16 bits • Dword: 32 bits

5. Multiplication Operation • Unsigned multiplication: MUL • Code: MUL Operand • If Operand is a byte, e.g. MUL BL, thenAX = AL*Operand • If Operand is a word, e.g., MUL BX, thenDX:AX = AX*Operand • If Operand is a dword, e.g., MUL EBX, thenEDX:EAX = EAX*Operand • Signed multiplication: IMUL • (look up the code table)

6. Division Operation • Unsigned division: DIV • Code: DIV Operand • If Operand is a byte, e.g. DIV BL, thenAL = AX/Operand AH = Rest • If Operand is a word, e.g., DIV BX, thenAX = DX:AX/Operand DX = Rest • If Operand is a dword, e.g., DIV EBX, thenEAX = EDX:EAX/Operand EDX = Rest • Signed division: IDIV • (look up the code table)

7. Stack Push/Pop Examples • … run out of registersPush EAX //save EAX on the stackPush EBX //save EBX on the stack … use EAX and EBX for some calculations …Pop EBX //move top of the stack to EBXPop EAX //move top of the stack to EAX to restore its original value • Note the orders of PUSH and POP are reversed

8. Function Call __declspec(naked) int add_func(int param1) { __asm{ PUSH ebx; PUSH ecx; // 1. Access param1 MOV ebx, dword ptr[esp+12]; MOV ecx, ebx; ADD ecx, 5; // 2. The return value should be placed in EAX MOV eax, ecx; POP ecx; POP ebx; // 3. Return to the caller RET; } } void main() { int result = 0; __asm{ PUSH eax; PUSH ebx; PUSH ecx; // 1. Pass parameter(s) to the procedure MOV ebx, 10; PUSH ebx; // 2. Execute call CALL add_func; // 3. Remove parameter(s) from the stack POP ebx; // 4. EAX has the return value MOV result, eax; POP ecx; POP ebx; POP eax; } }

9. Function (cont.) void main() { int result = 0; __asm{ PUSH eax; PUSH ebx; PUSH ecx; // 1. Pass parameter(s) to the procedure MOV ebx, 10; PUSH ebx; // 2. Execute call CALL add_func; // 3. Remove parameter(s) from the stack POP ebx; // 4. EAX has the return value MOV result, eax; POP ecx; POP ebx; POP eax; } }

10. Function (cont.) __declspec(naked) int add_func(int param1) { __asm{ PUSH ebx; PUSH ecx; // 1. Access param1 MOV ebx, dword ptr[esp+12]; MOV ecx, ebx; ADD ecx, 5; // 2. The return value should be placed in EAX MOV eax, ecx; POP ecx; POP ebx; // 3. Return to the caller RET; } }

11. Number Systems • Decimal (10) • Binary (2) • Hexadecimal (16) • Octal (8) • Conversion between them

12. Logical Operations • Get a bit • Using AND/OR • Count number of ones • Using DIV • Using AND and SHR • Mirror a byte

13. Recursion • Recursion in computer programming is exemplified when a function is defined in terms of itself. • Base case • Recursive case • E.g. Factorial(n) as: • Base case: • n=0 or n=1: Factorial(n)= 1 • Recursive case: • n>1 : n * Factorial(n-1)

14. Data Structures • Linked List • Element has • Value • Pointer to next element • Binary Search Tree • Element has • Value • Pointer to left child • Pointer to right child • Value of left subtree < root < right subtree • Insert and Traverse