assembly

C++ need for Assembly in embedded systems

I hear of a need to call assembly functions/calls when programming embedded systems in C. Is this necessary in C++ or not? ...

Storing two x86 32 bit registers into 128 bit xmm register

Is there any faster method to store two x86 32 bit registers in one 128 bit xmm register? movd xmm0, edx movd xmm1, eax pshufd xmm0, xmm0, $1 por xmm0, xmm1 So if EAX is 0x12345678 and EDX is 0x87654321 the result in xmm0 must be 0x8765432112345678. Thanks ...

ASM (from ObjectWeb) not calculating MaxStack correctly even though ClassWriter( COMPUTE_MAX + COMPUTE_STACK ) is set

I am getting expected ClassVerifyErrors when attempting to load a class i have generated using ASM. On further inspection i can see that the jvm is correct and that the method is talking about has an invalid MAX_STACK value. THe strange thing is am using the auto calculate the stack and max local options so this should not be a problem.....

Patching a PE executable

hey everybody, lets say i've loaded a PE executable into memory and suited it with dos,nt headers structures and now i want to find out its .text/code segement actual(not VA) offset+size how do i do that? is there a win32 api for finding the .text start offset or maybe a pointer from a sturcture that points to the start offset of that s...

Assembly/Linking problem with nasm and ld

I have a sample assembly file that I compile with nasm: nasm -f elf syscall.asm This generates a syscall.o file. I try to link it with ld: ld -o syscall syscall.o The ld command fails with the following error: ld: i386 architecture of input file `syscall.o' is incompatible with i386:x86-64 output However, if I do ld -o syscall...

Z80: How to add 16 and 8 bit registers?

How do you add a 16 and a 8 bit register with carry (for example, HL, and A)? ...

absolute Value of double

I am trying write a function named absD that returns the absolute value of its argument. I do not want to use any predefined functions. Right now i am getting a parse error when i try to compile it. I would image all i would have to do to get the absolute value of a double is change the sign bit? this is what i have #include <stdio.h> ...

Assembly language

I am very much a rookie. I am sure this is very basic but I have gone over this a number of times. I am trying to get my program to display a string on two different lines. This is a .com program and I am using A86 compiler. This is for HW and i am not trying to cheat or anything like that because I really want to know what I am doin...

Working with double-precision numbers in inline assembly (GCC, IA-32)

I'm just starting to learn assembly in my computer science class, and I have an assignment to round a floating-point value using a specified rounding mode. I've tried to implement this using fstcw, fldcw, and frndint. I modify the rounding control bits, round the number, and then restore the previous control bits (a requirement of the as...

Setting break points in z390 Portable Mainframe Assembler and Emulator?

I've been using the old Dos version of Assist and would like to use the z390 Portable Mainframe Assembler and Emulator instead. I'm able to compile and run programs but am not clear on how to set break points. For example in assist given the following section of an assembly listing 000006 5020C03A 00003C (1/21)21 ...

masm division overflow

I'm trying divide two numbers in assembly. I'm working out of the Irvine assembly for intel computers book and I can't make division work for the life of me. Here's my code .code main PROC call division exit main ENDP division PROC mov eax, 4 mov ebx, 2 div ebx call WriteDec ret divison ENDP END main Whe...

'Assembly Language Step-by-Step' on Mac OS X?

Hi, I am following through the book Assembly Language Step by Step and it says the book is for computers running Linux. What are the necessary tools to use the book with Snow Leopard? Thanks. EDIT: The book uses the Kate editor. So, preferable something that does the same thing as Kate. ...

floating point - absolute value - inline assembly - edited new code

I wrote a function named absD that i want to return the absolute value of its argument.. I am using GCC inline assembly with cygwin.. I dont see why its not working. i m loading into memory. then into st(0) where i am using fabs - absolute value. Do i have to allocate memory? I am trying to learn assembly with C here so please be nice....

Using assembly JMP function on x86_64

I'm really new to programming (in general - it's pathetic) and some Python-related assembly has cropped up in this app that I'm hacking to run on 64-bit. Essentially, the code goes like this: #define FUNCTION(name) \ .globl _##name; \ _##name: \ jmp *(_p_##name) .text FUNCTION(name) Th...

Include syntax on MASM32

When including files into MASM32, it cannot find it's own files. After including masm32rt.inc, the assembler cannot find \masm32\include\windows.inc Apparently most MASM system include files begin with \ instead of specyfing a relative or absolute path. I tried specifying the directory in %PATH%, setting the /I compile switch, and sett...

What is at memory location 1 on an Intel x86 machine running Windows XP?

I am running Windows XP on an Intel x86 machine and I got an error in the instruction at memory location 0x00000001. I am not worried about debugging the error, but I was interested to know what instructions would generally be located at the very begging of memory. The only processors I have written low-level code for are PIC microc...

BIOS Programming

Is it possible to call windows libraries that will live on the hard disk from a program that lives in the bios? I'm trying to write a program that will be a BIOS option (after POST). I'd like the application to have a nice GUI instead of being text based (there are multiple reasons for this, localization being one of them). My problem...

reverse engineering c programs

every c program is converted to machine code, if this binary is distributed. Since the instruction set of a computer is well known, is it possible to get back the C original program? ...

OpenGL Calls Lock/Freeze

I am using some dell workstations(running WinXP Pro SP 2 & DeepFreeze) for development, but something was recenlty loaded onto these machines that prevents any opengl call(the call locks) from completing(and I know the code works as I have tested it on 'clean' machines, I also tested with simple opengl apps generated by dev-cpp, which wi...

partition and mbr recovery

how do you read mbr and partition table from the hard disk and edit it? I want to know exactly how do the partition recovery softwares work? ...