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Recent Posts
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The Campus / Re: trouble with external variables
« Last post by TWell on July 28, 2017, 05:46:12 PM »An another example:
Code: [Select]
.386
.model flat, stdcall
option casemap :none
includelib msvcrt
printf proto C :ptr byte, :vararg
exit proto C :dword
includelib MyDll1
extern _imp__MyNum :dword
.data
fmt db "%p",10,0
MyNum1 dd ?
.code
mainCRTStartup proc C
mov eax, _imp__MyNum
mov eax, dword ptr[eax]
mov MyNum1, eax
invoke printf,addr fmt, MyNum1
invoke exit,0
mainCRTStartup endp
end
Code: [Select]
000000053
The Campus / Re: trouble with external variables
« Last post by aw27 on July 28, 2017, 04:33:09 PM »In DLL:
extern "C" const int MyNum = 5;
In .DEF
LIBRARY MYDLL
EXPORTS
MyNum = MyNum CONSTANT
In MASM:
Tested and works.
extern "C" const int MyNum = 5;
In .DEF
LIBRARY MYDLL
EXPORTS
MyNum = MyNum CONSTANT
In MASM:
Code: [Select]
.686
.model Flat, STDCALL
option Casemap :None
includelib \masm32\lib\msvcrt.lib
printf proto C :ptr, :vararg
includelib mydll.lib
externdef MyNum : sdword
.data
format db 'MyNum is %d', 13,10,0
.code
start1 proc public
mov edx, MyNum
mov edx, [edx]
INVOKE printf, addr format, edx
ret
start1 endp
main proc C public
invoke start1
ret
main endp
end
Tested and works.
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The Campus / Re: trouble with external variables
« Last post by hutch-- on July 28, 2017, 01:04:03 PM »I don't know if C++ decorates the external function name but I would try STDCALL as the calling convention.
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The Campus / trouble with external variables
« Last post by oinka720 on July 28, 2017, 12:50:19 PM »Hi all. This ought to be simple but I can't figure it out. I have a test dll written in c++
and then I have a test asm where I try to access the variable
it assembles and links, but ...
Problem1: it prints a random number rather than the expected 5.
Problem2: if I uncomment the line ;mov MyNum, 5 I get a runtime error "access violation"
Any assistance is appreciated. Thanks.
Code: [Select]
// MyDLL.cpp : Defines the exported functions for the DLL application.
//
#include "stdafx.h"
extern "C" __declspec( dllexport ) public int MyNum = 5;and then I have a test asm where I try to access the variable
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; «««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««
; Build this with the "Project" menu using
; "Console Assemble and Link"
; «««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««
.486 ; create 32 bit code
.model flat, stdcall ; 32 bit memory model
option casemap :none ; case sensitive
include \masm32\include\windows.inc ; always first
include \masm32\macros\macros.asm ; MASM support macros
; -----------------------------------------------------------------
; include files that have MASM format prototypes for function calls
; -----------------------------------------------------------------
include \masm32\include\masm32.inc
include \masm32\include\gdi32.inc
include \masm32\include\user32.inc
include \masm32\include\kernel32.inc
include \masm32\include\msvcrt.inc
; ------------------------------------------------
; Library files that have definitions for function
; exports and tested reliable prebuilt code.
; ------------------------------------------------
includelib \masm32\lib\masm32.lib
includelib \masm32\lib\gdi32.lib
includelib \masm32\lib\user32.lib
includelib \masm32\lib\kernel32.lib
includelib \masm32\lib\msvcrt.lib
includelib mydll.lib
.code ; Tell MASM where the code starts
; «««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««
start: ; The CODE entry point to the program
;mov MyNum, 5
push MyNum
push offset format
call crt_printf
exit
; «««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««««
.data
format db 'MyNum is %i', 13,10,0
extern MyNum:dword
end start ; Tell MASM where the program ends
it assembles and links, but ...
Problem1: it prints a random number rather than the expected 5.
Problem2: if I uncomment the line ;mov MyNum, 5 I get a runtime error "access violation"
Any assistance is appreciated. Thanks.
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The Soap Box / Re: A really good looking salt water crocodile.
« Last post by hutch-- on July 28, 2017, 12:10:14 PM »Looks great, will have to find a viewable copy. My dad spent a lot of time in the northern part of West OZ and then the Northern Territory before ww2 and was familiar with very large salt water crocodiles before they were shot out by hunters and he said that the best way to stop one charging at you was a 12 gauge shotgun into their open mouth. Back then it was reasonably common to get old ones that were 20 feet long and over. Since they have been protected about 30 years ago they are now almost epidemic and are moving a long way up waterways so you are at risk being anywhere near their habitat.
Don't go swimming in the rivers up north at night time and mostly in the daylight either or you will end up as a crocodile's breakfast.
Don't go swimming in the rivers up north at night time and mostly in the daylight either or you will end up as a crocodile's breakfast.
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The Workshop / Re: Introduction + Silly Question :)
« Last post by hutch-- on July 28, 2017, 10:18:41 AM »I have split this topic as I think Rob's original question has been answered and placed the following discussion in another thread so it is dealt with as discussion, not advice to the original poster.
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The Workshop / Re: Discussion + Introduction + Silly Question :)
« Last post by raymond on July 28, 2017, 07:02:05 AM »Quote
For Delphi, Free Pascal and other languages it is a snapI have been told that Python is not able to use the 80-bit floats at all.
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The Workshop / Re: Discussion + Introduction + Silly Question :)
« Last post by TWell on July 28, 2017, 06:33:45 AM »one example is the use of extended double-precision floats (80-bit).long double in gcc, icc ?
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The Workshop / Re: Discussion + Introduction + Silly Question :)
« Last post by aw27 on July 28, 2017, 06:26:19 AM »one example is the use of extended double-precision floats (80-bit).
Actually it is a problem of software that depends on the CRT library.
For Delphi, Free Pascal and other languages it is a snap.
http://www.delphibasics.co.uk/RTL.asp?Name=Extended