I have a relatively basic question, I've been having trouble calling a function from a separate file. My googling has come up short, there is a lot for the other languages but not much in the way of MIPS.
Any help would be appreciated
MIPS isn't a language, it is an instruction set architecture.
Assuming you really mean that you are programming in MIPS assembler AND you are using the GCC toolchain including GNU assembler, you need to declare your function with a .global myfunc in the file where it is implemented, then the linker should be able to resolve the function name where it is used in another file e.g. jal myfunc.
You don't need to use an .extern myfunc directive in the file where myfunc is used because the GNU tools treat all undefined symbols as external.
If you are using MARS, then none of this applies.
Related
Chisel provides the printf function for debugging purposes, when generating verilog, it becomes fwrite system function. How to use verilog simulation to output data to a file instead of the terminal only when the chisel code is modified. Can chisel's printf function do this?
The short answer appears to be no. But there are two issues filed about this
Can chisel implement printf to a file? #1290
Feature Request: Allow printfs to go to different file descriptors #1287
It might be a good PR to submit.
I'm trying to optimize some molecular simulation code (written completely in fortran) by using GPUs. I've developed a small subroutine that performs matrix vector multiplication using the cuBLAS fortran binding library (non-thunking - /usr/local/cuda/src/fortran.c on Linux).
When I tested the subroutine outside of the rest of the code (i.e. without any other external subroutine calls) everything worked. When I compiled, I used these tags -names uppercase -assume nounderscore. Without them, I would receive undefined reference errors.
When porting this into the main function of the molecular dynamics code, the -assume nounderscore -names uppercase tags mess up all of my other function calls in the main program.
Any idea of a way around this? Please refer to my previous question where -assume nounderscore -names uppercase was suggested here
Thanks in advance!
I would try Fortran-C interop. With something like
interface
function cublas_alloc(argument list) bind(C, name="the_binding_name")
defs of arguments
end function
end interface
the binding name can be upper case or lowercase, whatever you need, for example, bind(C,name="CUBLAS_ALLOC"). No underscores will be appended to that.
The iso_c_binding module might be also helpful.
Hey there,
if the env var "XYZ" is set WHILE compiling, than I want the part:
write (STDOUT,*) "Compiled with XYZ"
here one more function call bla()
to be compiled into the binary. If not, than not.
Any way to do it?
Thanks a lot!
You can't check environment variables while compiling, but you can pass options to the compiler -- termed preprocessing. This isn't heavily documented, but works with at least gfortran and intel ifort. On the compile line use, or not, "-DMYOPTION" (or whatever option name you select). Then in the code:
#ifdef MYOPTION
Fortran source code
#else
Fortran source code
#endif
Apparently that the preprocessor lines must start in the first column.
If you use filetype "F90" the preprocessor will be automatically invoked, otherwise you can use a compiler option to invoke this step.
Maybe this will answer your need? If not, you could you a command script to check the environment variable and use different compile commands depending on its value, to make the preprocessor method respond to an environment variable.
Of course, you can check environment variables at run-time with the intrinsic get_environment_variable .. simply using if statements to respond to a value might be easier.
As part of the Fortran 2008 standard, there are intrinsic functions for finding the compiler options and version it was compiled with. compiler options and compiler version. Fortran compilers are slowly coming up to date with the new standard; gfortran has it, it doesn't look like ifort 12 does yet:
program compilerinfo
use iso_fortran_env
implicit none
print *,'This program was compiled with ', compiler_version()
print *,'with flags ', compiler_options()
end program compilerinfo
and running gives
$ ./compilerinfo
This program was compiled with GCC version 4.6.0
with flags -mtune=generic -march=x86-64
NoOnly very newest Fortran compilers provide such a feature.
The nearest mechanism would be to write a program which obtains the environment variable and writes a Fortran subroutine containing the information needed. Add to the project build:
Running the program to grab the environment variable and write the subroutine
Compile the subroutine
Link the object into the rest of the project.
Edited to reflect Fortran 2008+ compilers
I'm currently working on a Mips Code Generator for my Pascal Parser (Written in C using Lex / Yacc) . Does anybode know of a Tool out there I can use as a reference in order assure correct Code Generation?
Here is a mips simulator. I used it in school to check and run my mips projcets. One thing I remember is that this simulator has a few commands(to make it easier on us students) that real mips compilers don't. I am pretty sure it is all documented tho.
You can build the GNU Pascal Compiler for a MIPS target, as a cross-compiler.
I know that executables contain instructions, but what exactly are these instructions? If I want to call the MessageBox API function for example, what does the instruction look like?
Thanks.
Executables are binary files that are understood by the operating system. The executable will contain sections which have data in them. Windows uses the PE format. The PE Format has a section which has machine instructions. These instructions are just numbers which are ordered in a sequence and is understood by the CPU.
A function call to MessageBox(), would be a sequence of instructions which will
1) have the address of the function which is in a DLL. This address is put in by the compiler
2) instructions to "push" the parameters onto a stack
3) The actual function call
4) some sort of cleanup (depends on the calling convention).
Its important to remember that EXE files are just specially formatted files. I dont have a disassembly for you, but you can try compiling your code, then open your EXE in visual studio to see the disassembly.
That is a bloated question if I ever saw one.
BUT, I will try my best to give an overview.
In a binary executable there are these things called "byte codes", byte codes are just the hex represtation of an instruction. Commonly you can "look up" byte codes and convert them to Assembly instructions. For example:
The instruction:
mov ax, 2h
Has the byte code representation:
B8 02 00
The byte codes get loaded into RAM and executed by the processer as that is its "language". No one sane that I know programs in byte code, it would just be wayyyy to complicated. Assembly is...fun enough as it is. Whenever you compile a program in a higher level language it has to take your code and turn it into Assembly instructions, you just imagine how mangled your code would look after it compiles it. Don't get me wrong, compilers are great, but disassemble a C++ program with IDA Pro Freeware and you will see what I am talking about.
That is executables in a nutshell, there are certainly books written on this subject.
I am not a Windows API expert, but someone else can show you what the instruction would look like for calling the Windows API "MessageBox". It should only be a few lines of Assembly.
Whatever code is written (be it in C or some other language) is compiled by a compiler to a special sort of language called assembly (well, machine code, but they're very close). Assembly is a very low-level language, which the CPU executes natively. Normally, you don't program in assembly because it is so low-level (for example, you don't want to deal with pulling bits back and forth from memory).
I can't say about the MessageBox function specifically, but I'd guess that it's a LOT of instructions. Think about it: it has to draw the box, and style it however your computer styles it, and hook up an even handler so that something happens when the user clicks the button, tells Windows (or whatever operating system) to add it to the taskbar (or dock, etc), and so many other things.
It depends on the language that you are working in. But for many it is as simple as...
msgbox("Your message goes here")
or
alert("Your message goes here")