Annoying ld linking problem

[drunkenfox]

So, I have successfully compiled an object file out of my c++ source

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#include "k_defines.h"

inline void outportb(unsigned int port, unsigned char value);

unsigned int panic(char *message);
void k_main();

void k_clear_screen();
unsigned int k_printf(char *message, unsigned int line);
void update_cursor(int row, int col);

void k_main()
{
	k_clear_screen();

	k_printf("Starting P-DOS...",0);
	update_cursor(1,0);
	k_printf("Nopony else is in here. Looks like I'm forever aLUNA. (How punny of me *induberdebly*)",3);
	update_cursor(5,0);
};

unsigned int k_printf(char *message, unsigned int line)
{
	char *vram = (char *) 0xb8000;
	unsigned int i=0;

	i=(line*80*2);

	while(*message!=0)
	{
		if(*message==0x2f)
		{
			*message++;
			if(*message==0x63)
			{
				line++;
				i=(line*80*2);
				*message++;
				if(*message==0)
				{
					return(1);
				};
			};
		};
		vram[i]=*message;
		*message++;
		i++;
		vram[i]=0x07;
		i++;
	};

	return(1);
};

void k_clear_screen()
{
	char *vram = (char *) 0xb8000;
	unsigned int i=0;
	while(i<(80*2*25))
	{
		vram[i]=' ';
		i++;
		vram[i]=WHITE_TXT;
		i++;
	};
};

inline void outportb(unsigned int port, unsigned char value)
{
	asm volatile ("outb %%al, %%dx"::"d" (port), "a" (value));
};

void update_cursor(int row, int col)
{
	USHORT position=(row*80)+col;

	outportb(0x3d4, 0x0f);
	outportb(0x3d5, (UCHAR)(position&0xff));

	outportb(0x3d4, 0x0e);
	outportb(0x3d5, (UCHAR)((position<<8)&0xff));
};

unsigned int panic(char *message)
{
	char *vram = (char *) 0xb8000;
	unsigned int i=0;
	unsigned int line=0;

	i=(line*80*2);

	while(*message!=0)
	{
		if(*message==0x2f)
		{
			*message++;
			if(*message==0x63)
			{
				line++;
				i=(line*80*2);
				*message++;
				if(*message==0)
				{
					return(1);
				};
			};
		};
		vram[i]=*message;
		*message++;
		i++;
		vram[i]=0x9; //use blue text
		i++;
	};

	return(1);
};

k_defines.h

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#define WHITE_TXT 0x7
#define BLUE_TXT 0x09

#define UCHAR unsigned char
#define USHORT unsigned short

kernel.ld

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OUTPUT_FORMAT("binary")
ENTRY(k_main)
SECTIONS
{
  .text  0x005000 : {
    code = .; _code = .; __code = .;
    *(.text)
    . = ALIGN(4096);
  }
  .data  : {
    data = .; _data = .; __data = .;
    *(.data)
    . = ALIGN(4096);
  }
  .bss  :
  {
    bss = .; _bss = .; __bss = .;
    *(.bss)
    . = ALIGN(4096);
  }
  end = .; _end = .; __end = .;
}

build script (batch)

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echo off
gcc-3 -c pony.cpp -o pony.o
ld -T kernel.ld -o PONY.SYS pony.o
copy PONY.SYS A:\PONY.SYS

pause

But I just get an error on the linker:

Code: Select all

ld: cannot perform PE operation on a non PE file 'PONY.SYS'

If anyone could help, it would be appreciated.

[bluemoon]

ld: cannot perform PE operation on a non PE file 'PONY.SYS'

Guess what? There is a wiki page for that. Cannot_perform_PE_operations_on_non-PE_file

[drunkenfox]

I'm trying get a flat binary. I don't want a PE. Btw, I have win xp and cygwin for the compiler.

[brain]

Are you REALLY sure you need a flat binary? Flat binary does not have facilities for relocation, symbol tables, and lots of other useful stuff. If you REALLY do need flat binary try the --oformat parameter to ld.

[drunkenfox]

It's going to be the real mode os loader after loaded at 0x500 by broken thorn's bootsector.

[Rudster816]

It's going to be the real mode os loader after loaded at 0x500 by broken thorn's bootsector.

You can't use GCC to produce 16 bit machine code. You're pretty much stuck with assembly for real mode unless you want to try and learn how to use the OpenWatcom compiler.

[Solar]

1) What bluemoon said, with a double "!!". Entering "PE operation on a non PE file" in the search engine of your choice would have pointed you right at the relevant information on this very website.

2) What Rudster816 said. You could also check out dev86, a dedicated 16bit toolchain.

[drunkenfox]

Alright got this fixed. All I had to do is switch to DJGPP.

[Hoozim]

Cygwin works fine, you need a cross-compiler. A cross-compiler is very simple to create. As pointed to above, there is an entire article on how to create one. There is also an article on why one is necessary.

[Combuster]

All I had to do is switch to DJGPP.

That's bound to give you many more problems later.