slae assembly primer Flashcards
What is the int operation?
interrupt, eg int 0x80 is system call
What are the fundamental data types?
Byte, Word, Double Word, Quad Word, Double Quad Word
How many bits is a byte?
8
How many bits is a word?
16
How many bits is a double word?
32
How many bits is a quad word?
64
How many bits is a double quad word?
128
What is a signed data structure?
A signed word uses 31 bits to store the value and the most significant bit to store the sign (+/-)
What is an unsigned data structure?
All 32 bits are used to store the value
What does eax equal - mov eax, message ?
$eax = *message , or address of message
What does eax equal: mov eax, [message] ?
$eax = message, or the value of message
What is resb 64?
Reserve 64 bytes
What is resw 1?
reserve a word
What is the $ special token?
evaluates the current line
What is the \$\$ special token?
evaluates to the beginning of the current section
What is the times instruction?
Repeat instruction eg times 100 movsb - movsb replicated 100 times
What are the four directions for the mov instruction?
- between registers
- Memory to register and register to memory
- Immediate data to register
- Immediate data to memory
What is LEA?
Load Effective Address - load pointer values (LEA EAX, [label] sets $eax to pointer of label)
What is XCHG?
Swap values , XCHG Register, Register or XCHG Register, Memory
