learn,how to mix C and Assembly Language ?, Basic Computer Science

learn,how to mix C and Assembly Language ?, Basic Computer Science

Assignment Help:

The technique to mix C and assembly language is to apply the "asm" directive. To access C-language variables from assembly language, you just use the C identifier that name is a memory operand. These variables cannot be local to a procedure, and also cannot be static within a procedure. They have to be global (but can be static global). The newline characters are essential.
unsigned long a1, r;
void junk( void )
{
asm(
"pushl %eax \n"
"pushl %ebx \n"
"movl $100,%eax \n"
"movl a1,%ebx \n"
"int $59 \n"
"movl %eax,r \n"
"popl %ebx \n"
"popl %eax \n"
);
}

This instance does the following:
1. Pushes the value stored in %eax and %ebx onto the stack.
2. Puts a value of 100 into %eax.
3. Copies the value in global variable a1 into %ebx.
4. Executes a software interrupt number 59.
5. Copies the value in %eax into the global variable r.
6. Restores (pops) the contents of the temporary registers %eax and %ebx.

Related Discussions:- learn,how to mix C and Assembly Language ?

Internal storage, Internal Storage: Internal storage is also known as ...

Internal Storage: Internal storage is also known as main, primary, or (for historical reasons) core storage, or, memory. It is used to hold those instructions and data require

Operating system, what is operating system

what is operating system

Basic parts of a computers, The basic parts of a computers are shown in Fig...

The basic parts of a computers are shown in Figure. Input devices such as a keyboard, mouse or scanner are used to enter input (data and/or instructions), directly

Types of software interface, different types of software interfaces which f...

different types of software interfaces which falls in different categories

Qbasic, write a program of circle of any colour

write a program of circle of any colour

Array, Array: Array : In programming, when large amount of related d...

Array: Array : In programming, when large amount of related data needs to be processed and each data element is stored with different a variable name, it becomes very diffic

Computer processing, Computer Processing: Most of the earliest compute...

Computer Processing: Most of the earliest computer memories have been based on physical elements which can exist in just one of the two states (on or off): such an element cor

Surveying, describe the two fundament purpose of surveying

describe the two fundament purpose of surveying

Research and development , Research and Development All intellectual ...

Research and Development All intellectual activities consciously pursued and systematically completed generate useful information. Research (also Research and Development) is

Data type, Data Type: Data Type: Anything that is processed by a comp...

Data Type: Data Type: Anything that is processed by a computer is called data. There are different types of data that can be given to the computer for processing. A data typ

Write Your Message!

Name

Email id

Message

Verfication Code

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

Submit Assignment

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd