How can I get the Watcom compiler (the forked version 2.0 beta which runs on 64-bit hosts) to output 8086 assembly source code in an ASM file? Running wcc -0 main.c from the command prompt produces just the OBJ file.
As a side note, my main task it to convert C source code to assembly code that I can run with EMU8086 (instead of writing the actual assembly code). I am hoping the ASM file generated by Watcom would run without modification (copy-paste) in EMU8086.
I don't see a way to get the Watcom compiler to generate an ASM file directly, but you should be able to use the Watcom disassembler (wdis) to generate an assembly listing from the object file produced by the compiler. In this case you would run something like wdis -l main to read main.obj and produce a file named main.lst that contains an assembly language listing.
If you recompile main.c with a -d1 or -d2 option to place extra debugging data into the main.obj file then you can use the disassembler's -s option to have the assembly language listing interpersed with comments showing the original C source from main.c.
To get the disassembler to omit descriptive comments and just give a plain disassembly that should be acceptable as a source file for the Watcom assembler, give the -a option to the disassembler. This option will also causes the disassembler's output to be written into main.asm rather than main.lst. Sorry, I have no idea whether this output will be directly consumable by EMU8086.
This is all discussed in the Open Watcom C/C++ User Guide and C/C++ Tools User Guide linked from http://www.openwatcom.com/doc.php
Related
Currently I am using Clion IDE plus latest version of Open Watcom v2 windows 32 bit compiler to develop some 16 bit MS-DOS application. The problem I have is I don't see all required debugging information when using watcom windows debugger (wdw.exe).
Being specific, I see global variables, global and any other types of functions, even those imported from asm files. But well, local variables list is empty all the time. But more importantly - the only c-code I can see is little test.c file which contains only main() function and nothing else except for includes.
What do I need to do to finally get c-level debugging for whole project? What am I missing?
I would be grateful for any help.
All source files is located in one directory, so, they all should be visible to debugger. But it sees only main c file.
Of course I am compiling with -d2 switch, as well as -hw. DEBUG WATCOM ALL is also presented in linker config file before any FILE directives. Reading manuals to compiler and linker... Well, it's nice that I've found many interesting things in manuals, but nothing helped with exactly that issue so far :)
List of compiler switches I currently using:
WCC.EXE:
CALL WCC.EXE -dTEST -bt=dos -0 -za99 -wx -we -mc -zp2 -hw -d2
%SRC_FULL_NAME%
WLINK:
CALL WLINK.EXE #..\CC.LK
CC.LK:
SYSTEM DOS
DEBUG WATCOM ALL
FILE TEST.OBJ
FILE LUTILS.OBJ
FILE LGL.OBJ
NAME TEST.EXE
OPTION ELIMINATE
...
I am trying to print all the Undefined function calls from a shared object file along with file name.
I tried with "nm" command, It print all the undefined function calls .But could not get the file name.
Example:
bash$ nm -u my_test.so
:
U _ZNSs4_Rep20_S_empty_rep_storageE##GLIBCXX_3.4
:
Environment : Ubuntu 18.04 , X86 Arch (Intel processor)
Study in details the specification of the DWARF format (which is the format used by debugging information on Linux). So you could extract the information (but it is not exactly simple) by parsing the DWARF inside your ELF binary.
Consider looking inside the source code of Ian Taylor's libbacktrace. It is doing this extraction of file name from DWARF inside ELF.
Perhaps your real problem is getting precise backtrace information, and then that libbacktrace is exactly what you need!
You might also use gdb : it is extensible and scriptable in Python (or Guile) and you could write your own specialized script.
Perhaps you'll better solve your real problem with some GCC plugin working when you compile your code.
Read How to write shared libraries by Drepper and read more about ELF.
You could for example collect all the undefined symbols in your shared library using nm (or readelf). Then a second script will find the occurrences of these in your source code. It could be even a simple awk script (or some for shell loop using grep), or something as sophisticated as a GCC plugin.
Your example shows (probably) a mangled C++ name. You could use nm -C to get it unmangled. And later write a GCC plugin to find all the GIMPLE CALL instructions using it.
Writing a GCC plugin may take some time, in particular if you are not familiar with GCC internals.
I'm trying to get started learning basic assembly with Paul A. Carter's book "PC Assembly Language." However I'm unable to run the first example Carter provides, so I'm kind of stuck until I figure this out.
I assembled the example "first.asm" without any problem, but I can't figure out how to link these files: first.obj, driver.c, asm_io.obj into an executable. In the comment section of first.asm Carter gives these instructions for creating an executable (I'm using Windows 10, VS community 2015 developer command prompt):
; Using MS C/C++
; nasm -f win32 first.asm
; cl first.obj driver.c asm_io.obj
I'm doing exactly that but I'm getting a fatal error 2 unresolved externals, _printf and _scanf. I have every necessary file that I can think of in the same directory, and I'm compiling in that directory.
Driver.c calls the function defined in and it uses a header file called "CDECL.h"; I have this file in my directory, but I don't understand much about this header file. I wonder if the problem is here. I haven't altered it or anything. I assembled asm_io.asm according to Dr. Carter's instructions.
Not too far into asm_io.asm is see this:
extern _scanf, _printf, _getchar, _putchar, _fputs
So here are the unresolved externals. Shouldn't they be defined in stdio.h? Driver.c includes stdio.h, shouldn't the linker be able to resolve these symbols be looking at stdio.h? What might I be missing?
ps. I'm new to programming in general, and this is my first stack overflow question. I'm open to any and all criticism/feedback. I'll provide more information if you need it, I just didn't want to post a massive wall of text and code if not necessary.
Welcome to SO. You need to understand:-
The difference between a header file, e.g.
foo.h // C or maybe C++ header file)
and a library, e.g.
foo.lib foo.dll // Windows
libfoo.a, libfoo.so // Unix/Linux
that implements the calling interface that is (merely) described in a header file.
The difference between compiling or assembling a source file, e.g.
bar.c // C source file
bar.asm // Assembly source, Windows
bar.s // Assembly source, Unix/Linux
to make an object file. e.g.
bar.obj // Windows
bar.o // Unix/Linux
and linking object files and libraries together make a complete executable.
Linking can succeed only if the linker is supplied with (or knows by default)
the names and locations of object files and/or libraries that provide
implementations of all the functions that are called in the program - including
functions whose calling interfaces are described in header files. Otherwise
unresolved symbol errors ensue.
Research these points and you'll quickly get yourself unstuck. See this
pretty good introductory tutorial, which although it is about getting
started with the GNU Compiler Collection rather
than with assembly language programming, will clarify the principles
and distinctions you need to grasp.
I was using Fortran g77 and experienced this problem:
c this program calculates runoff and sediment
1 2
Unrecognized statement name at (1) and invalid form for assignment or statement-function definition at (2)
Also, the compiler can recognized only .for file extension, not .f.
Does anyone know, where is the problem? I downloaded it from http://www.cse.yorku.ca/~roumani/fortran/ftn.htm.
The compiler is not recognizing that statement as a comment. As a comment it should ignore the line but it is trying parse it. Are you sure that the "C" is in the first column?
Why are you using g77? It hasn't been supported for years. gfortran is the current GNU Fortran compiler. It can compile FORTRAN 77, Fortran 90, 95 and portions of 2003 and 2008.
EDIT: Perhaps its wants an upper-case "C".
The page you have linked to states that the f2exe wrapper passes -ffree-form to the compiler:
Compilation Command
The above f2exe command is just a batch file that invokes g77, the "real" compilation command. The command:
g77 -ffree-form prog.for -oprog.exe
directs the compiler to compile the file prog.for and stores the output in the file prog.exe. The -ffree-form switch indicates free-form style (remove it if you are using the old style).
In free-form Fortran the only allowed comment format is that of a line starting with !. As a matter of fact, this is also written on the same page directly under the above text:
Comments
In free-form style, use ! for both full-line and in-line comments. In the old style, use a "C" in column-1.
If you are not using the provided f2exe wrapper, don't pass -ffree-form option when compiling fixed-form FORTRAN 77 code.
I'll assume you want to stick with this compiler.
As noted above, the problems you have come from using the F2EXE batch file, which is not very useful: first it automatically adds ".for" to the file name, so you can't compile ".f" files, and it assumes free-form syntax, which is unusual when programming in Fortran 77 (and if you want Fortran 90, find another compiler, other answers give you links).
Now, suppose you have written a program myprogram.f, and you are in a Windows command line, in the same directory where the program resides (use "cd C:\mydirectory" for example, to change)
You will compile with
g77 myprogram.f
If you use SLATEC, you use
g77 myprogram.f -lslatec
If you want to specify a name for your .exe file (default is a.exe), you write
g77 myprogram.f -o myprogram.exe
There are other useful options
g77 -O2 myprogram.f to optimize (within g77 2.95 limitations)
g77 -Wall myprogram.f to enable all compiler warnings, very useful
to find errors in your code
g77 -c myprogram.f to only compile (you get a .o file), this is
useful to compile functions and subroutines, to
later build a static library (.a file), like
libslatec.a which is given with the compiler
And to build a library, using ar.exe:
ar cru mylib.a myfunc1.o myfnuc2.o ...
Then you can use is with
g77 myprogram.f mylib.a
G77 runs in command line under Windows. You write programs in a text editor.
Notepad++ is fairly good and its free. See http://notepad-plus-plus.org/
If you have problems with compilation, maybe it comes from environment variables, so here are some precisions. You have to tell Windows where to find the G77 compiler (g77.exe).
You can follow instructions on the site where you downloaded it to change Windows' environment variables PATH and LIBRARY_PATH. It needs you install the compiler in the C:\F directory : that is, you will have C:\F\G77\bin, etc.
Slight modification to the instructions on that page :
You should set PATH to C:\F\G77\bin
And LIBRARY_PATH to C:\F\G77\lib;C:\F\SLATEC\lib
This modification to LIBRARY_PATH allows you to compile with SLATEC simply with "-lslatec" as above.
A note about the compiler. It's G77, also know as GNU Fortran 77. An old compiler, integrated with the well known GCC suite until GCC 3.4.6 (we are at GCC 4.7.2 now). And the compiler you downloaded is for version GCC 2.95.
It's a good Fortran 77 compiler, but it's not very well optimized, and of course, you don't get any support for new processor features such as Intel SSE.
Modern Fortran compilers can still understand most if not all of Fortran 77, plus all the newer features of Fortran 90 and newer standards, which are extremely useful.
It may also be interesting to know there is another place to download the same compiler (eccept there is no SLATEC), just in case the page gets destroyed :
http://www.mbr-pwrc.usgs.gov/software/g77.html
I am calling fortran 90 code from a c code. There is a main() (in c) that calls a wrapper function in the same file, that calls a fortran subroutine (actually in a liblibrary.a). I am working on linux. Now, I'm using gdb to debug the executable, but it cannot find the main.c file. I added the working directory using
directory /my/working/directory
but still it says there is no file named main.c
If I type list inside gdb it shows me a piece of fortran code. If I type show language, it says The current source language is auto; currently c.
If I run the executable and then I interrupt it and look to the stack it will show me the c-functions I am calling, but it will not state the source file, that instead will state for the fortran subroutine and function.
I am trying to investigate if I am passing the variables correctly from c to fortran and backwards, I suspect I am not.
The same thing happens in idb, more or less. when I try to put a break in main.c, it says not found. I compiled the fortran code with these flags:
-g -O0 -check bounds -warn all -traceback -align all -align rec8byte
and the c-code with:
-g -O0 -Wall
All suggestions are welcome.
Hello you need additional flag to put debug info into your executable.
Here is manual for intel compiler:
http://cache-www.intel.com/cd/00/00/34/75/347599_347599.pdf
Please try -debug full as on page 35 written.