32bit compile/link under 64bit linux

[xdcx]

edit: just neededed to

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%include "/usr/local/include/asm_io.inc"
where is the nasm directory in ubuntu, like windows?

why cant i compile, link and run 32bit assembly?

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i386 architecture of input file `asm1.o' is incompatible with i386:x86-64 output


[Frank Kotler]

Well... I'm not aware of any "Nasm include directory" or any "Nasm directory" (Windows may have one) except for the source directory if you built Nasm from source (.../nasm-x.y where x and y are version number). You can find Nasm itself (and ndisasm) by doing "which nasm" - probably /usr/bin or /usr/local/bin. There are no include files that "come with" Nasm.

"asm_io.inc" sounds like one of Dr. Paul Carter's files, although it could be anything. As I recall (it was a long time ago I downloaded it), his examples untarred into a single directory - that may have changed. Where did you put it? If you've lost track, "locate asm_io.inc" should find it. /usr/local/include might be a sensible place to put this stuff, but it isn't automatic (unless Ubuntu - apt-get or so - does something with... whatever you downloaded). ASSuming you've got Dr. Carter's stuff, besides "asm_io.inc" you'll need to link against "asm_io.o", which you may have to build from "asm_io.asm". You'll also need to find "driver.c". Be sure you got the examples package intended for Linux! http://www.drpaulcarter.com/pcasm I think...

As an alternative to putting the full path in your source...

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%include "/home/fbk/oldsrc/pctut/asm_io.inc"
(elsewhere on your system, no doubt), you can tell Nasm where to look by including the "-I" switch on the command line...

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nasm -f elf32 first.asm -I /home/fbk/oldsrc/pcasm/
(or wherever) Note that the trailing '/' is required! We have had several contributions eliminating this requirement, but they have all been rejected. RTFM: http://www.nasm.us/xdoc/2.10.05/html/nasmdoc2.html#section-2.1.16 under "really perverse" to see why.

You may, if you wish, set an environment variable NASMENV which will be appended to the command line. You can put one or more search directories ("-i" or "-I") here, if you wish. (RTFM if you need spaces in your pathnames) If you want to make /usr/local/include/ your "nasm include directory", this might be a good place to do it.

If I've misunderstood which "asm_io.inc" you're looking for, we can discuss it further, but I'm pretty sure you didn't get it "with Nasm".

Best,
Frank

[xdcx]

im on 64bit linux, but im working with 32 bit only, and yes i am using pcasm book

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nasm -f elf32 asm1.asm
gcc -m32 -c /usr/include/driver.c

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xdc@ubuntu:~$ gcc -m32 -o asm1.asm driver.o asm1.o /home/xdc/pcasm/asm_io.o

/usr/bin/ld: cannot find crt1.o: No such file or directory
/usr/bin/ld: cannot find crti.o: No such file or directory
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.7/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.7/libgcc_s.so when searching for -lgcc_s
/usr/bin/ld: cannot find -lgcc_s
/usr/bin/ld: cannot find -lc
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.7/libgcc.a when searching for -lgcc
/usr/bin/ld: cannot find -lgcc
/usr/bin/ld: skipping incompatible /usr/lib/gcc/x86_64-linux-gnu/4.7/libgcc_s.so when searching for -lgcc_s
/usr/bin/ld: cannot find -lgcc_s
/usr/bin/ld: cannot find crtn.o: No such file or directory
collect2: error: ld returned 1 exit status
without -m32

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xdc@ubuntu:~$ gcc -o asm1.asm driver.o asm1.o /home/xdc/pcasm/asm_io.o

/usr/bin/ld: i386 architecture of input file `driver.o' is incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `asm1.o' is incompatible with i386:x86-64 output
/usr/bin/ld: i386 architecture of input file `/home/xdc/pcasm/asm_io.o' is incompatible with i386:x86-64 output
/usr/bin/ld: driver.o: file class ELFCLASS32 incompatible with ELFCLASS64
/usr/bin/ld: final link failed: File in wrong format
collect2: error: ld returned 1 exit status


[Rob Neff]

I'm pretty sure your linker stage should be:

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gcc -m32 -lc -o PROGNAMEHERE asm1.o driver.o asm1.o /home/xdc/pcasm/asm_io.o
The crt1.o contains the C library startup code which should be found with the -lc switch.
Double check your asm source to make sure you didn't just hose it with your last gcc command.

[xdcx]

fixed

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sudo apt-get install gcc-multilib

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nasm -f elf32 asm1.asm
gcc -m32 -lc -o asm1 asm1.o /home/xdc/pcasm/driver.c /home/xdc/pcasm/asm_io.o

[Frank Kotler]

There ya go! I remembered that there was an issue with Ubuntu (an African word meaning "one ring to rule them all" /joke) not coming with the 32-bit libraries, and I remembered that there was a package that fixed it. "gcc-multilib", "gcc-multilib", "gcc-multilib"... I'll try to remember that. I'm sure you're not the last person who will run into it. Thanks!

Best,
Frank