What is Assembly Language?
WPbytes in sizeas compiled in the small model with Borland and Microsoft compilers with optimization on opt and off no opt. ASM ; Assembler subroutine to perform a bit checksum on the file ; opened on the passed-in handle.
Stores the result in the ; passed-in checksum variable. Returns 1 for success, 0 for error. Optimization makes code faster, but without proper design, optimization just creates fast slow code. Well, then, how are we going to improve our design?
Know the Territory Just why is Listing 1. The C library implements the read function by calling DOS to read the desired number of bytes. I figured this out by watching the code execute with a debugger, but you can buy library source code from both Microsoft and Borland.
That means that Listing 1. For starters, DOS functions are invoked with interrupts, and interrupts are among the slowest instructions of the x86 family CPUs. Then, DOS has to set up internally and branch to the desired function, expending more cycles in the process.
Finally, DOS has to search its own buffers to see if the desired byte has already been read, read it from the disk if not, store the byte in the specified location, and return.
All of that takes a long time—far, far longer than the rest of the main loop in Listing 1. In short, Listing 1. You can verify this for yourself by watching the code with a debugger or using a code profiler, but take my word for it: How can we speed up Listing 1. It should be clear that we must somehow avoid invoking DOS for every byte in the file, and that means reading more than one byte at a time, then buffering the data and parceling it out for examination one byte at a time.
The results confirm our theories splendidly, and validate our new design. As shown in Table 1. To the casual observer, read and getc would seem slightly different but pretty much interchangeable, and yet in this application the performance difference between the two is about the same as that between a 4.
Make sure you understand what really goes on when you insert a seemingly-innocuous function call into the time-critical portions of your code. In other words, know the territory!
Spend your time improving the performance of the code inside heavily-used loops and in the portions of your programs that directly affect response time.
Let C do what it does well, and use assembly only when it makes a perceptible difference. Always Consider the Alternatives Listing 1.Each model of computer has its own instruction set, and instructions vary depending on the architecture of the computer.
So each has its own unique assembly language (some have more than one) and thus there are many different ways to add two numbers. To write an assembly language program to perform division of bit signed number by 8-bit signed number.
To write an ALP to perform the division of two ASCII numbers. Tools: PC installed with TASM. Write and execute an alp to Microprocessor to add, subtract and multiply two 16 bit unsigned numbers.
Store the result in extra . * NUES. The student will submit a synopsis at the beginning of the semester for approval from the departmental committee in a specified format. The student will have to present the progress of the work through seminars and progress reports.
Besucher dieser Seite: ** Programmer's Technical Reference for MSDOS and the IBM PC ** USA copyright TXG ALL RIGHTS RESERVED.
Program - 4: Subtract two 8-bit numbers Sample problem: (H) (H) Result = 51H = 19H = 51H - 19H = 38H Write assembly language program with proper comments for the Documents Similar To Assembly Language Programs & Explanations 1.
Microprocessor by Ramesh S Gaonkar-Solution Manual. Apr 06, · The blog talks about variety of topics on Embedded System, microprocessor, microcontroller, ARM Architecture, C Architecture, C28x, AVR and many many more.