Fasm-TCC BareBones

转自:　http://wiki.osdev.org/Fasm-TCC_BareBones

The purpose of this article is to explain how to make a sample ELF kernel withFASM and Tiny C Compiler (aka TCC). TCC is a small and fast C compiler, which produces x86, x86_64 or ARM code, and generates PE or ELF executables. TCC is heading toward full ISOC99 compliance, and can compile itself, like FASM. Here are all features of TCC:

• TCC compiles C code about 9 times faster than GCC.
• TCC generates averagely optimized x86 code.
• TCC supports the ISO C99 standard (even if this support is not as complete as PCC).
• Under Linux, TCC can be used as a C interpreter (just add '#!/usr/local/bin/tcc -run' at the first line of your C source, and execute it directly from the command line).
• TCC has few dependencies. Only libc is required for its compilation.
• TCC includes a linker and an assembler (for x86 only).

Contents

• 1A small kernel example
  • 1.1 start32.asm
  • 1.2 kernel.c
• 2Compiling and linking

A small kernel example

This little example builds a small kernel in ELF format, which can be booted by Grub.

Note: The Windows version of TCC doesn't produces ELF executables, but only object files. You need to recompile TCC without PE support, if you want to use this tutorial on Windows.

start32.asm

;  Tutorial: A small kernel with Fasm & TCC;  By Tommy.         format elf        use32 ;; Equates;MULTIBOOT_PAGE_ALIGN    equ (1 shl 0)MULTIBOOT_MEMORY_INFO    equ (1 shl 1)MULTIBOOT_AOUT_KLUDGE    equ (1 shl 16)MULTIBOOT_HEADER_MAGIC    equ 0x1BADB002MULTIBOOT_HEADER_FLAGS    equ MULTIBOOT_PAGE_ALIGN or MULTIBOOT_MEMORY_INFOMULTIBOOT_CHECKSUM          equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)         section '.text' executable;; Multiboot header;dd MULTIBOOT_HEADER_MAGICdd MULTIBOOT_HEADER_FLAGSdd MULTIBOOT_CHECKSUM  ;; Kernel entry point.;        public  _start        extrn   kmain_start:        ; Call the main kernel function.        call    kmain @@:        jmp     @b

kernel.c

/*  Tutorial: A small kernel with Fasm & TCC *  By Tommy. */ /* * Main kernel function. */voidkmain (void){    *((unsigned char *) 0xB8000) = 'H';    *((unsigned char *) 0xB8001) = 0x1F;    *((unsigned char *) 0xB8002) = 'E';    *((unsigned char *) 0xB8003) = 0x1F;    *((unsigned char *) 0xB8004) = 'L';    *((unsigned char *) 0xB8005) = 0x1F;    *((unsigned char *) 0xB8006) = 'L';    *((unsigned char *) 0xB8007) = 0x1F;    *((unsigned char *) 0xB8008) = 'O';    *((unsigned char *) 0xB8009) = 0x1F;}

Compiling and linking

Assemble start32.asm with:

fasm start32.asm

Compile kernel.c with:

tcc -c kernel.c

Then link the whole thing with:

tcc -nostdlib -Wl,-Ttext,0x100000 start32.o kernel.o -o kernel-i386.elf

That's all!

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