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iansjack wrote:ld is complaining for exactly the reasons given in the error messages.

On a higher level, it is complaining because you don't know how to program in C.

Lukand wrote:Can you show us at least little bit more code?
If you are forcing us to judge why is ld complaining you may need to give us some more code.

# The kernel entry point.
.section .text
.global _start
.type _start, @function
_start:
	movl $stack_top, %esp

	# Call the global constructors.
	call _init

	# Transfer control to the main kernel.
	call kernel_main

	# Hang if kernel_main unexpectedly returns.
	cli
1:	hlt
	jmp 1b
.size _start, . - _start

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "string.h"
#include "vga.h"
 
static const size_t VGA_WIDTH = 80;
static const size_t VGA_HEIGHT = 25;
static uint16_t* const VGA_MEMORY = (uint16_t*) 0xB8000;
 
static size_t terminal_row;
static size_t terminal_column;
static uint8_t terminal_color;
static uint16_t* terminal_buffer;
 
void terminal_initialize(void) {
	terminal_row = 0;
	terminal_column = 0;
	terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
	terminal_buffer = VGA_MEMORY;
	for (size_t y = 0; y < VGA_HEIGHT; y++) {
		for (size_t x = 0; x < VGA_WIDTH; x++) {
			const size_t index = y * VGA_WIDTH + x;
			terminal_buffer[index] = vga_entry(' ', terminal_color);
		}
	}
}
 
void terminal_setcolor(uint8_t color) {
	terminal_color = color;
}
 
void terminal_putentryat(unsigned char c, uint8_t color, size_t x, size_t y) {
	const size_t index = y * VGA_WIDTH + x;
	terminal_buffer[index] = vga_entry(c, color);
}
 
void terminal_putchar(char c) {
	unsigned char uc = c;
	terminal_putentryat(uc, terminal_color, terminal_column, terminal_row);
	if (++terminal_column == VGA_WIDTH) {
		terminal_column = 0;
		if (++terminal_row == VGA_HEIGHT)
			terminal_row = 0;
	}
}
 
void terminal_write(const char* data, size_t size) {
	for (size_t i = 0; i < size; i++)
		terminal_putchar(data[i]);
}
 
void prints(const char* data) {
	terminal_write(data, strlen(data));
}

#ifndef ARCH_I386_VGA_H
#define ARCH_I386_VGA_H
 
#include <stdint.h>
 
enum vga_color {
	VGA_COLOR_BLACK = 0,
	VGA_COLOR_BLUE = 1,
	VGA_COLOR_GREEN = 2,
	VGA_COLOR_CYAN = 3,
	VGA_COLOR_RED = 4,
	VGA_COLOR_MAGENTA = 5,
	VGA_COLOR_BROWN = 6,
	VGA_COLOR_LIGHT_GREY = 7,
	VGA_COLOR_DARK_GREY = 8,
	VGA_COLOR_LIGHT_BLUE = 9,
	VGA_COLOR_LIGHT_GREEN = 10,
	VGA_COLOR_LIGHT_CYAN = 11,
	VGA_COLOR_LIGHT_RED = 12,
	VGA_COLOR_LIGHT_MAGENTA = 13,
	VGA_COLOR_LIGHT_BROWN = 14,
	VGA_COLOR_WHITE = 15,
};
 
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg) {
	return fg | bg << 4;
}
 
static inline uint16_t vga_entry(unsigned char uc, uint8_t color) {
	return (uint16_t) uc | (uint16_t) color << 8;
}
 
#endif

NunoLava1998 wrote:

iansjack wrote:ld is complaining for exactly the reasons given in the error messages.

On a higher level, it is complaining because you don't know how to program in C.

Except the 2 are part of boot.S which i NEVER modified or tty.c which i never modified except for renaming terminal_writestring to prints.

• You did not included apporiate header with prints() definition.
• You did not declared prints() in any header at all.

Lukand wrote:If you keep trying to hide your OS that could be written for 5 minutes, for 2 mins if you copy paste meaty skeleton as you did, there's few things I could suspect:

• You did not included apporiate header with prints() definition.
• You did not defined prints() in any header at all.

void terminal_writestring(const char* data) {
	terminal_write(data, strlen(data));
}

void prints(const char* data) {
	terminal_write(data, strlen(data));
}

NunoLava1998 wrote:

Code: Select all

enum vga_color {
	VGA_COLOR_BLACK = 0,
	VGA_COLOR_BLUE = 1,
	VGA_COLOR_GREEN = 2,
	VGA_COLOR_CYAN = 3,
	VGA_COLOR_RED = 4,
	VGA_COLOR_MAGENTA = 5,
	VGA_COLOR_BROWN = 6,
	VGA_COLOR_LIGHT_GREY = 7,
	VGA_COLOR_DARK_GREY = 8,
	VGA_COLOR_LIGHT_BLUE = 9,
	VGA_COLOR_LIGHT_GREEN = 10,
	VGA_COLOR_LIGHT_CYAN = 11,
	VGA_COLOR_LIGHT_RED = 12,
	VGA_COLOR_LIGHT_MAGENTA = 13,
	VGA_COLOR_LIGHT_BROWN = 14,
	VGA_COLOR_WHITE = 15,
};

enum vga_color {
	VGA_COLOR_BLACK,
	VGA_COLOR_BLUE,
	VGA_COLOR_GREEN,
	VGA_COLOR_CYAN,
	VGA_COLOR_RED,
	VGA_COLOR_MAGENTA,
	VGA_COLOR_BROWN,
	VGA_COLOR_LIGHT_GREY,
	VGA_COLOR_DARK_GREY,
	VGA_COLOR_LIGHT_BLUE,
	VGA_COLOR_LIGHT_GREEN,
	VGA_COLOR_LIGHT_CYAN ,
	VGA_COLOR_LIGHT_RED,
	VGA_COLOR_LIGHT_MAGENTA,
	VGA_COLOR_LIGHT_BROWN,
	VGA_COLOR_WHITE
};

const uint8_t VGA_COLOR_BLACK = 0,
              VGA_COLOR_BLUE = 1,
              VGA_COLOR_GREEN = 2,
              VGA_COLOR_CYAN = 3,
              VGA_COLOR_RED = 4,
              VGA_COLOR_MAGENTA = 5,
              VGA_COLOR_BROWN = 6,
              VGA_COLOR_LIGHT_GREY = 7,
              VGA_COLOR_DARK_GREY = 8,
              VGA_COLOR_LIGHT_BLUE = 9,
              VGA_COLOR_LIGHT_GREEN = 10,
              VGA_COLOR_LIGHT_CYAN = 11,
              VGA_COLOR_LIGHT_RED = 12,
              VGA_COLOR_LIGHT_MAGENTA = 13,
              VGA_COLOR_LIGHT_BROWN = 14,
              VGA_COLOR_WHITE = 15;

NunoLava1998 wrote:However, GCC compiled fine with -w. I use -w beacuse some errors in my code are intended and if they aren't GCC will just fix it anyway

Love4Boobies wrote:Generally speaking, I actually find grouping related constants into enumerated types more elegant because (a) they're not meant to be objects (which const int's are), and (b) the type itself can be used for documentation purposes. Consider the following example:

Code: Select all

enum somename {
    FOO = 0xDEADBEEF,
    BAR = 0xC0DECAFE
};

void foo(const enum somename);

You can tell the set of values that were meant to be passed to foo just by looking at its prototype.

Schol-R-LEA wrote:I think we need to see the code for init and strlen, the header file they are declared in, and your Makefile and linker script.

Or, you know, you could give us a link to your cloud repo. The one you probably don't have yet because you never listen to advice. Go, drop everything, head over to GitHub or CloudForge and make one right now, and get your code under version control before you do anything else. You are sitting on a bomb that is about to go off and you don't even realize it.

Seriously, you really are the fool we have been taking you for if you don't do this right away.

Speaking of which:

NunoLava1998 wrote:

Code: Select all

enum vga_color {
	VGA_COLOR_BLACK = 0,
	VGA_COLOR_BLUE = 1,
	VGA_COLOR_GREEN = 2,
	VGA_COLOR_CYAN = 3,
	VGA_COLOR_RED = 4,
	VGA_COLOR_MAGENTA = 5,
	VGA_COLOR_BROWN = 6,
	VGA_COLOR_LIGHT_GREY = 7,
	VGA_COLOR_DARK_GREY = 8,
	VGA_COLOR_LIGHT_BLUE = 9,
	VGA_COLOR_LIGHT_GREEN = 10,
	VGA_COLOR_LIGHT_CYAN = 11,
	VGA_COLOR_LIGHT_RED = 12,
	VGA_COLOR_LIGHT_MAGENTA = 13,
	VGA_COLOR_LIGHT_BROWN = 14,
	VGA_COLOR_WHITE = 15,
};

You do know that enum will automagically set the values in a fixed order starting at zero for you if you don't set an explicit value, right? That's the whole point of enumerations. Change it to this and it will actually be more readable to most C programmers:

Code: Select all

enum vga_color {
	VGA_COLOR_BLACK,
	VGA_COLOR_BLUE,
	VGA_COLOR_GREEN,
	VGA_COLOR_CYAN,
	VGA_COLOR_RED,
	VGA_COLOR_MAGENTA,
	VGA_COLOR_BROWN,
	VGA_COLOR_LIGHT_GREY,
	VGA_COLOR_DARK_GREY,
	VGA_COLOR_LIGHT_BLUE,
	VGA_COLOR_LIGHT_GREEN,
	VGA_COLOR_LIGHT_CYAN ,
	VGA_COLOR_LIGHT_RED,
	VGA_COLOR_LIGHT_MAGENTA,
	VGA_COLOR_LIGHT_BROWN,
	VGA_COLOR_WHITE
};

As I said in the other thread, the values of an enumeration are more or less a side effect of how they are implemented. Using them for those values is sort of off-brand, but permissible in C, but the whole idea of an enum is to define the order of the constants, not the specific values. If the order doesn't matter, use const or #define for general constants. In this case, it really isn't, so using an enumeration for it is a Bad Idea. This is really a better solution all around:

Code: Select all

const uint8_t VGA_COLOR_BLACK = 0,
              VGA_COLOR_BLUE = 1,
              VGA_COLOR_GREEN = 2,
              VGA_COLOR_CYAN = 3,
              VGA_COLOR_RED = 4,
              VGA_COLOR_MAGENTA = 5,
              VGA_COLOR_BROWN = 6,
              VGA_COLOR_LIGHT_GREY = 7,
              VGA_COLOR_DARK_GREY = 8,
              VGA_COLOR_LIGHT_BLUE = 9,
              VGA_COLOR_LIGHT_GREEN = 10,
              VGA_COLOR_LIGHT_CYAN = 11,
              VGA_COLOR_LIGHT_RED = 12,
              VGA_COLOR_LIGHT_MAGENTA = 13,
              VGA_COLOR_LIGHT_BROWN = 14,
              VGA_COLOR_WHITE = 15;

I won't bother mentioning that this isn't a good way to do that anyway, because VGA palettes aren't fixed, but whatever.

i686-elf-as boot.s -o boot.o
i686-elf-gcc -c kernel.c -o kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra -w
i686-elf-gcc -T linker.ld -o myos.bin -ffreestanding -O2 -nostdlib boot.o kernel.o -lgcc REM failure right here, REM is the same as # in Assembly or /* */ in C, but in Batch. You can put REM after commands.

call _init

Hi,


GCC will not fix errors automagically if invoked with the -w option. It will just refrain from reporting warnings (and not errors). Errors and warnings will continue to exist, although the latter won't be reported.