MASM64 is a 64-bit version of the MASM32 software development environment (SDK) for programmers using Microsoft's Assembler (MASM) to target 64-bit Windows. DO NOT USE THIS TAG FOR REGULAR 64-BIT ASSEMBLY PROGRAMMING (instead use [x86-64] and [assembly]).
Questions tagged [masm64]
60 questions
1
vote
1 answer
Tabulate function Y=3.3\*log(2)(x^2+1)
Can't log2 to masm64. How exactly do I apply fyl2x in my code? I can't figure out where to apply this piece of code. Basically, the program crashes, or incorrect data. Here is my code:
\`include win64a.inc
.data
\_x dq 3.0
\_op1 dq 3.3
\_op2 dq…
Ana_406
- 11
- 2
1
vote
0 answers
MASM64 reverse tcp shell - cmd not binding to socket
I'm trying to write code that creates a reverse connection and binds a cmd.exe to a socket.
There are no errors - I created socket, connecttion and the cmd process started in the OS, but in the console with netcat I see only successful connect and…
Slava
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- 1
- 3
1
vote
1 answer
Correctly Setting Up Stack Pointer in x64 Assembly on Windows with Masm + LOCALS
I have the follow simple program I'm trying to build targeting x64 on Windows 10 building with MASM:
WSTR MACRO lbl:req,qstr:VARARG
LOCAL arg,unq,qot,q
lbl LABEL WORD
FOR arg,
qot SubStr ,1,1
q = 0
IFIDNI…
Malcolm McCaffery
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1
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1 answer
How to horizontally sum signed bytes in XMM
I am writing some code in x64 assembly and using SIMD.
I have 9 bytes packed in the xmm15 register. For simplicity, let's look at the following code:
.data
Masks BYTE 0, -1, 0, -1, 5, -1, 0, -1, 0
.code
GetSumOfMasks proc
movdqu xmm15, xmmword ptr…
nooblet2
- 31
- 6
1
vote
1 answer
My MASM code shows 3 errors after debugging, but I do not know how to fix them. Can someone help me?
;programul citeste de la tastatura doua numere intregi si le afiseaza.
.386 ;folosim instructiuni cu operanzi pe 32 biti
.MODEL FLAT, C ;memoria este organizata liniar si conventia de apel a functiilor este cea din C
.STACK 100h …
Elena Isabella
- 23
- 6
1
vote
1 answer
How to call a x64 Assembly procedure in C#
I am working on a project and currently have the following structure:
C# WPF project containing the User Interface as well as calls to external methods.
C++ DLL project containing an algorithm.
ASM DLL project containing an algorithm.
For…
nooblet
- 31
- 1
- 9
1
vote
1 answer
Why am I getting this error in the assembly code below?
This is my first trial running an assembly code for x64 in MASM:
_text SEGMENT
main PROC
mov ah,0
ret
main ENDP
_text ENDS
END
and I'm getting a linker error LNK2001: unresolved external symbol mainCRTStartup. Why?
I have the entry point…
João Afonso
- 1,934
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1
vote
0 answers
Detecting potential MASM 64-bit sign extension errors for immediate 32-bit operands (imm32)
I'm trying to write a tool to scan 64-bit assembly code looking for possible sign extension errors.
For example, suppose a 32-bit constant (imm32) is defined as
SOCKET_ERROR_INT EQU 0FFFFFFFFh
Next, call any API that returns a SOCKET_ERROR (32-bit…
vengy
- 1,548
- 10
- 18
1
vote
2 answers
Why the gs segment register is address is set to 0x0000000000000000 on visual studio x64(MASM)?
I am currently reading "The Ultimate Anti Debugging Reference" and I am trying to implement some of the techniques.
To check the Value of the NtglobalFlag they use this code -
push 60h
pop rsi
gs:lodsq ;Process Environment Block
mov al,…
Cyber_Noob
- 89
- 9
1
vote
2 answers
Program run under x64dbg goes immediately to completion
I'm using the x64dbg debugger from SourceForge under Windows 10, and I've been having a problem with it that I think is probably due to my own stupidity somehow, but so far I can't pin it down.
I'm using the MASM assembler, and when I'm working on a…
Robert Watson
- 39
- 4
1
vote
0 answers
I get empty items when inserting them in Treeview
I have a problem using Treeview control, when I try to insert items it shows the first line empty without any caption as you can see in the picture:
Figure1
First,I declared a variable called TreeCaption which holds the item caption:
TreeCaption …
Rever7eR
- 11
- 6
1
vote
1 answer
Link assembly script with a resource file
I am trying to link my assembly script with a resource file made with ResEdit that both belong to the same directory with the .bat file:
@echo off
C:\masm64\ml64.exe dialog_box.asm /link /entry:Main resources.res /subsystem:windows…
Bart
- 11
- 1
1
vote
1 answer
LNK1104 when using MASM 64bit
I'm currently trying to learn Assembly for x64 Windows. I tried the example code from this Intel website,
but whenever I try to compile it with the command given in the document:
ml64 hello.asm /link /subsystem:windows /defaultlib:kernel32.lib…
ClusterFonk
- 49
- 4
0
votes
1 answer
Win32 CALL to CreateFileW always returns ERROR_INVALID_PARAMETER in MASM x64. Why?
I'm currently trying to learn MASM x64, and so far I seem to be getting the hang of things pretty well. Everything was going well right up until I tried to call CreateFileW to read the contents of a .txt file. The problematic code is as follows:
…
FireController1847
- 1,458
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0
votes
1 answer
Use .obj created by MASM (ml64) with gcc on linux
I have a .obj file that is created by ml64 and then used by a vsxproj to compile a windows dll. The C part simply acts as a pass-through to one function in the masm code.
Is it possible to do the same with gcc so I can compile a linux .so…
BJury
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