ASSEMBLER - X86

Assembler  --- Assembly instructions into Machine Code Instructions.

When the assembly instructions is sent into the ASM , the named 'variables' are hard-coded as memory address and ;label' variables as code address. Some parts of the prog source are always lost when assembler is used,which is inevitable.

MASM   -  Microsoft Assembler. (Macro Assembler)

•  Used by Microsoft systems for the low-part definition of the Operating systems.
•  Used for Intel core.
•  This is not portable and hence is the disadvantage with other platforms.

TASM   - Turbo assembler

•  Developed by Borland and used in integration with Borland's software development tools.
•  This assembler is not free .

NASM   -  Netwide Assembler

• Free, portable and retargetable. 
• Can be used both in Linux and Windows systems.
• Not mature as TASM and MASM,but definitely user-friendly.

FASM  -   Flat Assembler

• Fast Self-assembling Open-source (X86) assembler .

AT & T Syntax

• AT&T syntax is different from Intel Syntax, but is used in GAS (GNU Assembler) ,mainly distributed in Unix and Unix-based Systems.
• GAS is specifically designed to be used as the back-end of GCC (GNU Compiler Collection) package.
• GCC always feeds it syntactically correct code,GAS often has minimal error checking.
• GAS syntax can be switched to Intel syntax with the directive  ":intel_syntax noprefix"
• GAs is automatically installed with GCC or GNU binutils distribution package.

                              

HLA   -   High Level Assemblers

• An assembler with high-level syntax. 
• HLA acts as a front-end to other assemblers as FASM, MASM , NASM and GAS. So, the programmer must have another assembler installed to assemble programs with HLA.
• HLA comes with a comprehensive standard library.
• HLA syntax is very easy and closely resembles to C.                                                                      

      Example of a HLA code : 

            

            mov (src, dest) ;

            pop(eax) ;

            push(ebp) ;

            for (mov (0, ecx) ; ecx < 10; inc (exc)) do

                    mul (ecx) ;

            endfor ;