Table of Contents
How string is stored in assembly language?
String Instructions MOVS − This instruction moves 1 Byte, Word or Doubleword of data from memory location to another. LODS − This instruction loads from memory. STOS − This instruction stores data from register (AL, AX, or EAX) to memory. CMPS − This instruction compares two data items in memory.
How are strings represented in assembly?
A string is represented as an array of char.
What is DQ in NASM?
Looking at the nasm source, it looks like: ‘oword’/’DO’ is 8 times as big as “word” (O for “octoword”), synonymous with dqword (“double-quad”); that would be 128 bits, corresponding to the size of an SSE vector register. ‘tword’/’DT’ is 80 bits (T for “ten bytes”), the full size of an Intel x87 floating point register.
How do I move a string into a register assembly?
In general you can’t fit a string into a register, as registers tend to be short- 8, 16, 32, or 64 bits. You can only put 1 to 8 ASCII characters into a typical register. What one usually does is to load the address of a string into a register, then you fetch a byte at a time by using that register indirectly.
What does $$ mean in NASM?
$$ evaluates to the beginning of the current section; so you can tell how far into the section you are by using ($−$$).
What is push in NASM?
push src. Insert a value onto the stack. Useful for passing arguments, saving registers, etc. push ebp. pop dest.
What are string manipulation instructions?
String manipulation instructions in 8086 microprocessor
| OPCODE | OPERAND | EXPLANATION |
|---|---|---|
| REP | instruction | repeat the given instruction till CX != 0 |
| REPE | instruction | repeat the given instruction while CX = 0 |
| REPZ | instruction | repeat the given instruction while ZF = 1 |
| REPNE | instruction | repeat the given instruction while CX != 0 |
How do you display variables in assembler?
To list the contents of a single variable, move the cursor to an occurrence of the variable name in the Source window and press PF4 ( LIST ). The value is displayed in the Log window. This is equivalent to entering LIST variable on the command line.
Which directive is used to define 16 bit data?
DB = define byte size variables. DW = define word size (16 bits) variables.
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