Use cross compiler, added automated cross compiler build script. Closes #67

.gitignore

@@ -10,3 +10,4 @@ kernel/o/
 *.swp
 *.d
 genInitrd/make_initrd
+cross/

COMPILING.md

@@ -0,0 +1,43 @@
+To compile Q-OS you need to compile a cross compiler.
+
+Needed packages
+---------------
+
+    gcc 5.x
+    g++ 5.x
+    GNU Make
+    GNU Bison
+    Flex
+    Texinfo
+    ISL (optional)
+    CLooG (optional)
+
+For Mac users:
+If you use OS X 10.7 or older you need to install gcc and do this:
+
+    # This is only necessary for OS X users running 10.7 or below.
+    export CC=/usr/bin/gcc-5.X
+    export CXX=/usr/bin/g++-5.X
+    export CPP=/usr/bin/cpp-5.X
+    export LD=/usr/bin/gcc-5.X
+
+note: don't make these permanent
+
+Installing
+----------
+Run build_cross_compiler.sh script.
+After it's finished run:
+
+    . ./set_path.sh
+
+Note: you need to do that every time you start new console sessioi. Or permanently change your $PATH.
+
+Compiling Q-OS
+--------------
+To compile:
+
+    make
+
+To compile and run:
+
+    make qemu

Makefile

@@ -3,15 +3,16 @@
 ASM:=nasm
 #ASM flags
 ASMFLAGS:=-f elf32
+LD:=i686-elf-ld
 
 #C compiler
-CC:=gcc
+CC:=i686-elf-gcc
 #C compiler flags
 WARNINGS:=-Wall -Wextra #-pedantic -Wshadow -Wpointer-arith -Wcast-align \
             #-Wwrite-strings -Wmissing-prototypes -Wmissing-declarations \
             #-Wredundant-decls -Wnested-externs -Winline -Wno-long-long \
             #-Wuninitialized -Wconversion -Wstrict-prototypes -Werror
-CFLAGS:=-m32 -ffreestanding -std=c99 -Werror -pedantic $(WARNINGS)
+CFLAGS:=-ffreestanding -std=c99 -Werror -pedantic $(WARNINGS)
 #object file directory
 
 ODIR:=kernel/o
@@ -54,7 +55,7 @@ $(ISO): $(KERNEL) $(INITRD)
 
 $(KERNEL): $(CSOURCES) $(ASOURCES) $(COBJECTS) $(AOBJECTS)
 	@mkdir -p $(IMGDIR)/boot/
-	@ld -m elf_i386 -T $(DIR)/link.ld $(AOBJECTS) $(COBJECTS) -o $(IMGDIR)/boot/$@
+	@$(LD) -m elf_i386 -T $(DIR)/link.ld $(AOBJECTS) $(COBJECTS) -o $(IMGDIR)/boot/$@
 
 $(INITRD):
 

build-cross-compiler.sh

@@ -0,0 +1,47 @@
+#!/bin/sh
+
+mkdir cross
+cd cross
+
+export PREFIX="$(pwd)"
+export TARGET="i686-elf"
+export PATH="$PREFIX/bin:$PATH"
+
+echo $PREFIX $TARGET $PATH
+
+BINUTILS_VER="binutils-2.25.1"
+wget http://ftp.gnu.org/gnu/binutils/$BINUTILS_VER.tar.bz2
+tar -xvf $BINUTILS_VER.tar.bz2
+mkdir build-binutils
+cd build-binutils
+../$BINUTILS_VER/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
+make -j4
+make install
+cd ..
+
+GMP_VER="gmp-6.1.0"
+MPFR_VER="mpfr-3.1.3"
+MPC_VER="mpc-1.0.3"
+GCC_VER="gcc-5.3.0"
+#prepare GCC for installation
+wget https://gmplib.org/download/gmp/$GMP_VER.tar.lz
+wget http://www.mpfr.org/mpfr-current/$MPFR_VER.tar.gz
+wget ftp://ftp.gnu.org/gnu/mpc/$MPC_VER.tar.gz
+tar --lzip -xvf $GMP_VER.tar.lz
+tar -xvf $MPFR_VER.tar.gz
+tar -xvf $MPC_VER.tar.gz
+wget ftp://ftp.gnu.org/gnu/gcc/gcc-5.3.0/$GCC_VER.tar.gz
+tar -xvf $GCC_VER.tar.gz
+mv $GMP_VER $GCC_VER/gmp
+mv $MPFR_VER $GCC_VER/mpfr
+mv $MPC_VER $GCC_VER/mpc
+
+which -- $TARGET-as || echo $TARGET-as is not in the PATH
+
+mkdir build-gcc
+cd build-gcc
+../$GCC_VER/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers
+make -j4 all-gcc
+make -j4 all-target-libgcc
+make install-gcc
+make install-target-libgcc

set_path.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+contains() {
+    string="$1"
+    substring="$2"
+    if test "${string#*$substring}" != "$string"
+    then
+        return 0    # $substring is in $string
+    else
+        return 1    # $substring is not in $string
+    fi
+}
+
+cd cross
+export PREFIX="$(pwd)"
+export TARGET="i686-elf"
+export ADD_PATH="$PREFIX/bin"
+if ! contains $PATH  $ADD_PATH
+then
+    export PATH="$ADD_PATH:$PATH"
+    echo "PATH set to $PATH"
+else
+    echo "Path already set"
+fi
+cd ..