Chapter 3.5, Problem 3.10PP

Explanation of Solution

Given program:

x in %rdi, y in %rsi, z in %rdx

arith2:

orq %rsi, %rdi

sarq $3, %rdi

notq %rdi

movq %rdx, %rax

subq %rdi, %rax

ret

Data movement instructions:

• The different instructions are been grouped as “instruction classes”.
• The instructions in a class performs same operation but with different sizes of operand.
• The “Mov” class denotes data movement instructions that copy data from a source location to a destination.
• The class has 4 instructions that includes:
  • movb:
    • It copies data from a source location to a destination.
    • It denotes an instruction that operates on 1 byte data size.
  • movw: 
    • It copies data from a source location to a destination.
    • It denotes an instruction that operates on 2 bytes data size.
  • movl:
    • It copies data from a source location to a destination.
    • It denotes an instruction that operates on 4 bytes data size.
  • movq:
    • It copies data from a source location to a destination.
    • It denotes an instruction that operates on 8 bytes data size.
• The “subq” instruction decrements the second operand by value in first operand.

Shift Operations:

• In these instructions, the shift amount is given as first operand and shift value as second operand.
• The instruction “sar” denotes shift right instruction.
  • The instruction “sarq” would shift right by 63.
• The instruction “sal” denotes shift left instruction.
  • The instruction “salq” would shift left by 63.

Logical Instructions:

• The instructions provided by processor includes:
  • AND
    • It performs bitwise “AND” operation.
    • It returns 1, if matching bits from both operands are 1.
  • OR
    • It performs bitwise “OR” operation.
    • It returns 1, if matching bits from either or both operands are 1.
  • XOR
    • It performs bitwise “XOR” operation...