Cross compiler
Encyclopedia
A cross compiler is a compiler
capable of creating executable
code for a platform
other than the one on which the compiler is run. Cross compiler tool
s are used to generate executables for embedded system
or multiple platforms. It is used to compile for a platform upon which it is not feasible to do the compiling, like microcontroller
s that don't support an operating system
. It has become more common to use this tool for paravirtualization
where a system may have one or more platforms in use.
Not targeted by this definition are source to source translators
, which are often mistakenly called cross compilers.
Use of virtual machine
s (such as Java's JVM
) resolves some of the reasons for which cross compilers were developed. The virtual machine paradigm allows the same compiler output to be used across multiple target systems, although this is not always ideal because virtual machines are often slower and the compiled program can only be run on computers with that virtual machine.
Typically the hardware architecture
differs (e.g. compiling a program destined for the MIPS architecture
on an x86 computer) but cross-compilation is also applicable when only the operating system
environment differs, as when compiling a FreeBSD
program under Linux
, or even just the system library, as when compiling programs with uClibc
on a glibc host.
on an IA-32
processor) to build a cross compiler that runs on machine B (e.g. running Mac OS X
on an x86-64
processor) to create executables for machine C (e.g. running Android on an ARM
processor). When using the Canadian Cross with GCC, there may be four compilers involved:
The end-result cross compiler (4) will not be able to run on your build machine A; instead you would use it on machine B to compile an application into executable code that would then be copied to machine C and executed on machine C.
For instance, NetBSD
provides a POSIX
Unix shell
script named
with the host's compiler; this, in turn, will be used to build the cross-compiler which will be used to build the whole system.
The term Canadian Cross came about because at the time that these issues were all being hashed out, Canada had three national political parties.
, a free software
collection of compilers, can be set up to cross compile. It supports many platforms and languages.
GCC requires that a compiled copy of binutils be available for each targeted platform. Especially important is the GNU Assembler
. Therefore, binutils first has to be compiled correctly with the switch
, which can be done using the following (on UNIX-like operating systems with bash):
PATH=/path/to/binutils/bin:${PATH} make
Cross compiling GCC requires that a portion of the target platforms C standard library
be available on the host platform. At least the crt0
, ... components of the library must be available. You may choose to compile the full C library, but that can be too large for many platforms. The alternative is to use newlib
, which is a small C library containing only the most essential components required to compile C
source code. To configure GCC with newlib, use the switch
The GNU autotools
packages (i.e. autoconf
, automake
, and libtool
) use the notion of a build platform, a host platform, and a target platform. The build platform is where the compiler is actually compiled. In most cases, build should be left undefined (it will default from host). The host platform is where the output artefacts from the compiler will be executed. The target platform is used when cross compiling cross compilers, it represents what type of object code the package itself will produce; otherwise the target platform setting is irrelevant. For example, consider cross-compiling a video game that will run on a Dreamcast. The machine where the game is compiled is the host platform while the Dreamcast is the target platform.
Another method that is popularly used by embedded Linux developers is to use gcc, g++, gjc etc. with scratchbox or the newer scratchbox2. These tools create a "chroot"ed sandbox where you can build up your tools, libc, and libraries without having to set extra paths. It also has facilities for tricking the runtime into thinking it is on (for example) an ARM CPU so things like configure scripts will run. The downside to scratchbox is that it is slower and you lose access to most of your tools that are on the host. The speed loss is not terrible and you can move host tools into scratchbox.
, New Jersey
, produced C compilers
beginning in the 1980s targeted at professional developers for a variety of platforms up to and including PCs
and Macs
.
Manx's Aztec C
programming language
was available for a variety of platforms including MS DOS, Apple II
DOS 3.3
and ProDOS
, Commodore 64
, Macintosh
68XXX and Amiga
.
From the 1980s and continuing throughout the 1990s until Manx Software Systems disappeared, the MS DOS version of Aztec C was offered both as a native mode compiler or as a cross compiler for other platforms with different processors including the Commodore 64 and Apple II. Internet distributions still exist for Aztec C including their MS DOS based cross compilers. They are still in use today.
Manx's Aztec C86, their native mode 8086
MS DOS compiler, was also a cross compiler. Although it did not compile code for a different processor like their Aztec C65 6502
cross compilers for the Commodore 64 and Apple II, it created binary executables for then-legacy operating systems for the 16 bit 8086 family of processors.
When the IBM PC was first introduced it was available with a choice of operating systems, CP/M 86 and PC DOS being two of them. Aztec C86 was provided with link libraries for generating code for both IBM PC
operating systems. Throughout the 1980s later versions of Aztec C86 (3.xx, 4.xx and 5.xx) added support for MS DOS "transitory" versions 1 and 2 and which were less robust than the "baseline" MS DOS version 3 and later which Aztec C86 targeted until its demise.
Finally, Aztec C86 provided C language developers with the ability to produce ROM-able
"HEX"
code which could then be transferred using a ROM Burner directly to an 8086 based processor. Paravirtualization
may be more common today but the practice of creating low-level ROM code was more common per-capita during those years when device driver
development was often done by application programmers for individual applications, and new devices amounted to a cottage industry. It was not uncommon for application programmers to interface directly with hardware without support from the manufacturer. This practice was similar to Embedded Systems Development
today.
Thomas Fenwick and James Goodnow II were the two principal developers of Aztec-C. Fenwick later became notable as the author of the Microsoft
Windows CE
Kernel or NK ("New Kernel") as it was then called.
and were rebranded by Microsoft as their own, until MSC 4 was released, which was the first version that Microsoft produced themselves.
In 1987 many developers started switching to Microsoft C, and many more would follow throughout the development of Microsoft Windows to its present state. Products like Clipper and later Clarion emerged that offered easy database application development by using cross language techniques, allowing part of their programs to be compiled with Microsoft C.
. Most C compilers (even current compilers) offer an assembly language pass (that can be tweaked for efficiency then linked to the rest of the program after assembling).
Compilers like Aztec-C converted everything to assembly language as a distinct pass and then assembled the code in a distinct pass, and were noted for their very efficient and small code, but by 1987 the optimizer built into Microsoft C was very good, and only "mission critical" parts of a program were usually considered for rewriting. In fact, C language programming had taken over as the "lowest-level" language, with programming becoming a multi-disciplinary growth industry and projects becoming larger, with programmers writing user interfaces and database interfaces in higher-level languages, and a need had emerged for cross language development that continues to this day.
By 1987, with the release of MSC 5.1, Microsoft offered a cross language development environment for MS DOS. 16 bit binary object code written in assembly language (MASM) and Microsoft's other languages including Quick Basic, Pascal
, and Fortran
could be linked together into one program, in a process they called "Mixed Language Programming" and now "InterLanguage Calling". If BASIC
was used in this mix, the main program needed to be in BASIC to support the internal run-time system
that compiled BASIC required for garbage collection and its other managed operations that simulated a BASIC interpreter
like QBasic
in MS DOS.
The calling convention
for C code in particular was to pass parameters in "reverse order" on the stack
and return values on the stack rather than in a processor register
. There were other programming rules to make all the languages work together, but this particular rule persisted through the cross language development that continued throughout Windows
16 and 32 bit versions and in the development of programs for OS 2, and which persists to this day. It is known as the Pascal calling convention.
Another type of cross compilation that Microsoft C was used for during this time was in retail applications that require handheld device
s like the Symbol Technologies
PDT3100 (used to take inventory
), which provided a link library targeted at an 8088
based barcode reader
. The application was built on the host computer then transferred to the handheld device (via a serial cable
) where it was run, similar to what is done today for that same market using Windows Mobile
by companies like Motorola
, who bought Symbol.
compliant compiler) Microsoft re-focused their C compilers on the emerging Windows market, and also on OS 2 and in the development of GUI
programs. Mixed language compatibility remained through MSC 6 on the MS DOS side, but the API for Microsoft Windows 3.0 and 3.1 was written in MSC 6. MSC 6 was also extended to provide support for 32-bit assemblies and support for the emerging Windows for Workgroups and Windows NT
which would form the foundation for Windows XP
. A programming practice called a thunk
was introduced to allow passing between 16 and 32 bit programs that took advantage of runtime binding (dynamic linking) rather than the static binding that was favoured in monolithic
16 bit MS DOS applications. Static binding is still favoured by some native code developers but does not generally provide the degree of code reuse
required by newer best practices like the Capability Maturity Model
(CMM).
MS DOS support was still provided with the release of Microsoft's first C++ Compiler, MSC 7, which was backwardly compatible with the C programming language and MS DOS and supported both 16 bit and 32 bit code generation.
MSC took over where Aztec C86 left off. The market share for C compilers had turned to cross compilers which took advantage of the latest and greatest Windows features, offered C and C++ in a single bundle, and still supported MS DOS systems that were already a decade old, and the smaller companies that produced compilers like Aztec C could no longer compete and either turned to niche markets like embedded systems or disappeared.
MS DOS and 16 bit code generation support continued until MSC 8.00c which was bundled with Microsoft C++ and Microsoft Application Studio 1.5, the forerunner of Microsoft Visual Studio
which is the cross development environment that Microsoft provide today.
and Windows 98
code generation as well as for Windows NT
. Link libraries were available for other processors that ran Microsoft Windows; a practice that Microsoft continues to this day.
MSC 13 was released with Visual Studio 2003, and MSC 14 was released with Visual Studio 2005, both of which still produce code for older systems like Windows 95, but which will produce code for several target platforms including the mobile market and the ARM architecture
.
(CLR), which formed the core for their .NET Framework
compiler in the Visual Studio IDE. This layer on the operating system which is in the API
allows the mixing of development languages compiled across platforms that run the Windows operating system.
The .NET Framework runtime and CLR provide a mapping layer to the core routines for the processor and the devices on the target computer. The command-line C compiler in Visual Studio will compile native code for a variety of processors and can be used to build the core routines themselves.
Microsoft .NET applications for target platforms like Windows Mobile
on the ARM architecture
cross-compile on Windows machines with a variety of processors and Microsoft also offer emulators and remote deployment environments that require very little configuration, unlike the cross compilers in days gone by or on other platforms.
Runtime libraries, such as Mono
, provide compatibility for cross-compiled .NET programs to other operating systems, such as Linux
.
Libraries like Qt
and its predecessors including XVT
provide source code level cross development capability with other platforms, while still using Microsoft C to build the Windows versions. Other compilers like MinGW
have also become popular in this area since they are more directly compatible with the Unixes that comprise the non-Windows side of software development allowing those developers to target all platforms using a familiar build environment.
was developed from the beginning as a cross compiler. The compiler executable (ppcXXX where XXX is a target architecture) is capable of producing executables (or just object files if no internal linker exists, or even just assembly files if no internal assembler exists) for all OS of the same architecture. For example, ppc386 is capable of producing executables for i386-linux, i386-win32, i386-go32v2 (DOS) and all other OSes (see ). For compiling to another architecture, however, a cross architecture version of the compiler must be built first. The resulting compiler executable would have additional 'ross' before the target architecture in its name. i.e if the compiler is built to target x64, then the executable would be ppcrossx64.
To compile for a chosen architecture-OS, the compiler switch (for the compiler driver fpc) -P and -T can be used. This is also done when cross compiling the compiler itself, but is set via make option CPU_TARGET and OS_TARGET. GNU assembler and linker for the target platform is required if Free Pascal doesn't yet have internal version of the tools for the target platform.
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
capable of creating executable
Executable
In computing, an executable file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a data file that must be parsed by a program to be meaningful. These instructions are traditionally machine code instructions for a physical CPU...
code for a platform
Platform (computing)
A computing platform includes some sort of hardware architecture and a software framework , where the combination allows software, particularly application software, to run...
other than the one on which the compiler is run. Cross compiler tool
Programming tool
A programming tool or software development tool is a program or application that software developers use to create, debug, maintain, or otherwise support other programs and applications...
s are used to generate executables for embedded system
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
or multiple platforms. It is used to compile for a platform upon which it is not feasible to do the compiling, like microcontroller
Microcontroller
A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
s that don't support an operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
. It has become more common to use this tool for paravirtualization
Paravirtualization
In computing, paravirtualization is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware....
where a system may have one or more platforms in use.
Not targeted by this definition are source to source translators
Source-to-source compiler
A source-to-source compiler is a type of compiler that takes a high level programming language as its input and outputs a high level language. For example, an automatic parallelizing compiler will frequently take in a high level language program as an input and then transform the code and annotate...
, which are often mistakenly called cross compilers.
Uses of cross compilers
The fundamental use of a cross compiler is to separate the build environment from target environment. This is useful in a number of situations:- Embedded computersEmbedded systemAn embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
where a device has extremely limited resources. For example, a microwave oven will have an extremely small computer to read its touchpad and door sensor, provide output to a digital display and speaker, and to control the machinery for cooking food. This computer will not be powerful enough to run a compiler, a file system, or a development environment. Since debugging and testing may also require more resources than are available on an embedded system, cross-compilation can be less involved and less prone to errors than native compilation. - Compiling for multiple machines. For example, a company may wish to support several different versions of an operating system or to support several different operating systems. By using a cross compiler, a single build environment can be set up to compile for each of these targets.
- Compiling on a server farmServer farmA server farm or server cluster is a collection of computer servers usually maintained by an enterprise to accomplish server needs far beyond the capability of one machine. Server farms often have backup servers, which can take over the function of primary servers in the event of a primary server...
. Similar to compiling for multiple machines, a complicated build that involves many compile operations can be executed across any machine that is free, regardless of its underlying hardware or the operating system version that it is running. - BootstrappingBootstrapping (compilers)In computer science, bootstrapping is the process of writing a compiler in the target programming language which it is intended to compile...
to a new platform. When developing software for a new platform, or the emulator of a future platform, one uses a cross compiler to compile necessary tools such as the operating system and a native compiler. - Compiling native code for emulators for older now-obsolete platforms like the Commodore 64 or Apple II by enthusiasts who use cross compilers that run on a current platform (such as Aztec C's MS DOS 6502MOS Technology 6502The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
cross compilers running under Windows XPWindows XPWindows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
).
Use of virtual machine
Virtual machine
A virtual machine is a "completely isolated guest operating system installation within a normal host operating system". Modern virtual machines are implemented with either software emulation or hardware virtualization or both together.-VM Definitions:A virtual machine is a software...
s (such as Java's JVM
Java Virtual Machine
A Java virtual machine is a virtual machine capable of executing Java bytecode. It is the code execution component of the Java software platform. Sun Microsystems stated that there are over 4.5 billion JVM-enabled devices.-Overview:...
) resolves some of the reasons for which cross compilers were developed. The virtual machine paradigm allows the same compiler output to be used across multiple target systems, although this is not always ideal because virtual machines are often slower and the compiled program can only be run on computers with that virtual machine.
Typically the hardware architecture
Hardware architecture
In engineering, hardware architecture refers to the identification of a system's physical components and their interrelationships. This description, often called a hardware design model, allows hardware designers to understand how their components fit into a system architecture and provides...
differs (e.g. compiling a program destined for the MIPS architecture
MIPS architecture
MIPS is a reduced instruction set computer instruction set architecture developed by MIPS Technologies . The early MIPS architectures were 32-bit, and later versions were 64-bit...
on an x86 computer) but cross-compilation is also applicable when only the operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
environment differs, as when compiling a FreeBSD
FreeBSD
FreeBSD is a free Unix-like operating system descended from AT&T UNIX via BSD UNIX. Although for legal reasons FreeBSD cannot be called “UNIX”, as the direct descendant of BSD UNIX , FreeBSD’s internals and system APIs are UNIX-compliant...
program under Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
, or even just the system library, as when compiling programs with uClibc
UClibc
In computing, uClibc is a small C standard library intended for embedded Linux systems. uClibc was created to support uClinux, a version of Linux not requiring a memory management unit and thus suited for microcontrollers .The project lead is Erik Andersen. The other main contributor is Manuel...
on a glibc host.
Canadian Cross
The Canadian Cross is a technique for building cross compilers for other machines. Given three machines A, B, and C, one uses machine A (e.g. running Windows XPWindows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
on an IA-32
IA-32
IA-32 , also known as x86-32, i386 or x86, is the CISC instruction-set architecture of Intel's most commercially successful microprocessors, and was first implemented in the Intel 80386 as a 32-bit extension of x86 architecture...
processor) to build a cross compiler that runs on machine B (e.g. running Mac OS X
Mac OS X
Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
on an x86-64
X86-64
x86-64 is an extension of the x86 instruction set. It supports vastly larger virtual and physical address spaces than are possible on x86, thereby allowing programmers to conveniently work with much larger data sets. x86-64 also provides 64-bit general purpose registers and numerous other...
processor) to create executables for machine C (e.g. running Android on an ARM
ARM
An arm is an upper limb of the body.Arm may also refer to:-Geography:* Arm , a narrow stretch of a larger body of water** Canal arm, a subsidiary branch of a canal or inland waterway** Distributary or arm, a subsidiary branch of a river...
processor). When using the Canadian Cross with GCC, there may be four compilers involved:
- The proprietary (describes goods which are made and sent out by a particular company whose name is on the product) native Compiler for machine A (1) (e.g. compiler from Microsoft Visual StudioMicrosoft Visual StudioMicrosoft Visual Studio is an integrated development environment from Microsoft. It is used to develop console and graphical user interface applications along with Windows Forms applications, web sites, web applications, and web services in both native code together with managed code for all...
) is used to build the gcc native compiler for machine A (2). - The gcc native compiler for machine A (2) is used to build the gcc cross compiler from machine A to machine B (3)
- The gcc cross compiler from machine A to machine B (3) is used to build the gcc cross compiler from machine B to machine C (4)
The end-result cross compiler (4) will not be able to run on your build machine A; instead you would use it on machine B to compile an application into executable code that would then be copied to machine C and executed on machine C.
For instance, NetBSD
NetBSD
NetBSD is a freely available open source version of the Berkeley Software Distribution Unix operating system. It was the second open source BSD descendant to be formally released, after 386BSD, and continues to be actively developed. The NetBSD project is primarily focused on high quality design,...
provides a POSIX
POSIX
POSIX , an acronym for "Portable Operating System Interface", is a family of standards specified by the IEEE for maintaining compatibility between operating systems...
Unix shell
Unix shell
A Unix shell is a command-line interpreter or shell that provides a traditional user interface for the Unix operating system and for Unix-like systems...
script named
build.sh which will first build its own toolchainToolchain
In software, a toolchain is the set of programming tools that are used to create a product...
with the host's compiler; this, in turn, will be used to build the cross-compiler which will be used to build the whole system.
The term Canadian Cross came about because at the time that these issues were all being hashed out, Canada had three national political parties.
Time line of early cross compilers
- 1979 – ALGOL 68CALGOL 68CThe ALGOL68C computer programming language compiler was developed for the CHAOS OS for the CAP capability computer at Cambridge University in 1971 by Stephen Bourne and Michael Guy as a dialect of ALGOL 68. Other early contributors were Andrew D. Birrell and Ian Walker.The initial compiler was...
generated ZCODE, this added on porting the compiler and other ALGOL 68 applications to alternate platforms. To compile the ALGOL 68C compiler required about 120kB of memory. With Z80 its 64kB memory is too small to actually compile the compiler. So for the Z80 the compiler itself had to be cross compiled from the larger CAP capability computerCAP computerThe Cambridge CAP computer was the first successful experimental computer that demonstrated the use of security capabilities, both in hardware and software. It was developed at the University of Cambridge Computer Laboratory in the 1970s...
or an IBM 370IBM 370The IBM 370 printer was used on the IBM 305 RAMAC computer system, introduced by IBM on September 14, 1956. The 370 was connected to the 305 by a serial data line from the S track of the computer's drum memory and printed 80-columns with a punched tape controlled carriage...
mainframe.
GCC and cross compilation
GCCGNU Compiler Collection
The GNU Compiler Collection is a compiler system produced by the GNU Project supporting various programming languages. GCC is a key component of the GNU toolchain...
, a free software
Free software
Free software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
collection of compilers, can be set up to cross compile. It supports many platforms and languages.
GCC requires that a compiled copy of binutils be available for each targeted platform. Especially important is the GNU Assembler
GNU Assembler
The GNU Assembler, commonly known as GAS , is the assembler used by the GNU Project. It is the default back-end of GCC. It is used to assemble the GNU operating system and the Linux kernel, and various other software. It is a part of the GNU Binutils package.GAS' executable is named after as, a...
. Therefore, binutils first has to be compiled correctly with the switch
--target=some-target sent to the configure script. GCC also has to be configured with the same --target option. GCC can then be run normally provided that the tools, which binutils creates, are available in the pathPath (computing)
A path, the general form of a filename or of a directory name, specifies a unique location in a file system. A path points to a file system location by following the directory tree hierarchy expressed in a string of characters in which path components, separated by a delimiting character, represent...
, which can be done using the following (on UNIX-like operating systems with bash):
PATH=/path/to/binutils/bin:${PATH} make
Cross compiling GCC requires that a portion of the target platforms C standard library
C standard library
The C Standard Library is the standard library for the programming language C, as specified in the ANSI C standard.. It was developed at the same time as the C POSIX library, which is basically a superset of it...
be available on the host platform. At least the crt0
Crt0
crt0 is a set of execution startup routines compiled into a program which perform any initialization work required before calling the program's main function. The work performed by crt0 depends on the program's language, compiler, operating system and C standard library implementation."crt" stands...
, ... components of the library must be available. You may choose to compile the full C library, but that can be too large for many platforms. The alternative is to use newlib
Newlib
Newlib is a C standard library implementation intended for use on embedded systems. It is a conglomeration of several library parts, all under free software licenses that make them easily usable on embedded products....
, which is a small C library containing only the most essential components required to compile C
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
source code. To configure GCC with newlib, use the switch
--with-newlib.The GNU autotools
GNU build system
The GNU build system, also known as the Autotools, is a suite of programming tools designed to assist in making source-code packages portable to many Unix-like systems....
packages (i.e. autoconf
Autoconf
GNU Autoconf is a tool for producing configure scripts for building, installing and packaging software on computer systems where a Bourne shell is available....
, automake
Automake
GNU Automake is a programming tool that produces portable makefiles for use by the make program, used in compiling software. It is made by the Free Software Foundation as one of GNU programs, and is part of the GNU build system. The makefiles produced follow the GNU Coding Standards.It is written...
, and libtool
Libtool
GNU Libtool is a GNU programming tool from the GNU build system used for creating portable compiled libraries. To quote the introduction in the :Libtool is typically used with Autoconf and Automake, two other tools of the GNU build system....
) use the notion of a build platform, a host platform, and a target platform. The build platform is where the compiler is actually compiled. In most cases, build should be left undefined (it will default from host). The host platform is where the output artefacts from the compiler will be executed. The target platform is used when cross compiling cross compilers, it represents what type of object code the package itself will produce; otherwise the target platform setting is irrelevant. For example, consider cross-compiling a video game that will run on a Dreamcast. The machine where the game is compiled is the host platform while the Dreamcast is the target platform.
Another method that is popularly used by embedded Linux developers is to use gcc, g++, gjc etc. with scratchbox or the newer scratchbox2. These tools create a "chroot"ed sandbox where you can build up your tools, libc, and libraries without having to set extra paths. It also has facilities for tricking the runtime into thinking it is on (for example) an ARM CPU so things like configure scripts will run. The downside to scratchbox is that it is slower and you lose access to most of your tools that are on the host. The speed loss is not terrible and you can move host tools into scratchbox.
Manx Aztec C cross compilers
Manx Software Systems, of ShrewsburyShrewsbury, New Jersey
Shrewsbury is a borough in Monmouth County, New Jersey, United States. As of the 2010 United States Census, the borough population was 3,809....
, New Jersey
New Jersey
New Jersey is a state in the Northeastern and Middle Atlantic regions of the United States. , its population was 8,791,894. It is bordered on the north and east by the state of New York, on the southeast and south by the Atlantic Ocean, on the west by Pennsylvania and on the southwest by Delaware...
, produced C compilers
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
beginning in the 1980s targeted at professional developers for a variety of platforms up to and including PCs
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
and Macs
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...
.
Manx's Aztec C
Aztec C
Aztec C is a C compiler for a variety of older computing platforms, including MS DOS, Apple II DOS 3.3 and ProDOS, Commodore 64, early Macintosh, CP/M-80 and Amiga.- History :...
programming language
C (programming language)
C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....
was available for a variety of platforms including MS DOS, Apple II
Apple II
The Apple II is an 8-bit home computer, one of the first highly successful mass-produced microcomputer products, designed primarily by Steve Wozniak, manufactured by Apple Computer and introduced in 1977...
DOS 3.3
Apple DOS
Apple DOS refers to operating systems for the Apple II series of microcomputers from late 1978 through early 1983. Apple DOS had three major releases: DOS 3.1, DOS 3.2, and DOS 3.3; each one of these three releases was followed by a second, minor "bug-fix" release, but only in the case of Apple DOS...
and ProDOS
ProDOS
ProDOS was the name of two similar operating systems for the Apple II series of personal computers. The original ProDOS, renamed ProDOS 8 in version 1.2, was the last official operating system usable by all Apple II series computers, and was distributed from 1983 to 1993...
, Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
, Macintosh
Macintosh
The Macintosh , or Mac, is a series of several lines of personal computers designed, developed, and marketed by Apple Inc. The first Macintosh was introduced by Apple's then-chairman Steve Jobs on January 24, 1984; it was the first commercially successful personal computer to feature a mouse and a...
68XXX and Amiga
Amiga
The Amiga is a family of personal computers that was sold by Commodore in the 1980s and 1990s. The first model was launched in 1985 as a high-end home computer and became popular for its graphical, audio and multi-tasking abilities...
.
From the 1980s and continuing throughout the 1990s until Manx Software Systems disappeared, the MS DOS version of Aztec C was offered both as a native mode compiler or as a cross compiler for other platforms with different processors including the Commodore 64 and Apple II. Internet distributions still exist for Aztec C including their MS DOS based cross compilers. They are still in use today.
Manx's Aztec C86, their native mode 8086
Intel 8086
The 8086 is a 16-bit microprocessor chip designed by Intel between early 1976 and mid-1978, when it was released. The 8086 gave rise to the x86 architecture of Intel's future processors...
MS DOS compiler, was also a cross compiler. Although it did not compile code for a different processor like their Aztec C65 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
cross compilers for the Commodore 64 and Apple II, it created binary executables for then-legacy operating systems for the 16 bit 8086 family of processors.
When the IBM PC was first introduced it was available with a choice of operating systems, CP/M 86 and PC DOS being two of them. Aztec C86 was provided with link libraries for generating code for both IBM PC
IBM PC
The IBM Personal Computer, commonly known as the IBM PC, is the original version and progenitor of the IBM PC compatible hardware platform. It is IBM model number 5150, and was introduced on August 12, 1981...
operating systems. Throughout the 1980s later versions of Aztec C86 (3.xx, 4.xx and 5.xx) added support for MS DOS "transitory" versions 1 and 2 and which were less robust than the "baseline" MS DOS version 3 and later which Aztec C86 targeted until its demise.
Finally, Aztec C86 provided C language developers with the ability to produce ROM-able
ROM image
A ROM image, or ROM file, is a computer file which contains a copy of the data from a read-only memory chip, often from a video game cartridge, a computer's firmware, or from an arcade game's main board...
"HEX"
Hexadecimal
In mathematics and computer science, hexadecimal is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F to represent values ten to fifteen...
code which could then be transferred using a ROM Burner directly to an 8086 based processor. Paravirtualization
Paravirtualization
In computing, paravirtualization is a virtualization technique that presents a software interface to virtual machines that is similar but not identical to that of the underlying hardware....
may be more common today but the practice of creating low-level ROM code was more common per-capita during those years when device driver
Device driver
In computing, a device driver or software driver is a computer program allowing higher-level computer programs to interact with a hardware device....
development was often done by application programmers for individual applications, and new devices amounted to a cottage industry. It was not uncommon for application programmers to interface directly with hardware without support from the manufacturer. This practice was similar to Embedded Systems Development
Embedded system
An embedded system is a computer system designed for specific control functions within a larger system. often with real-time computing constraints. It is embedded as part of a complete device often including hardware and mechanical parts. By contrast, a general-purpose computer, such as a personal...
today.
Thomas Fenwick and James Goodnow II were the two principal developers of Aztec-C. Fenwick later became notable as the author of the Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
Windows CE
Windows CE
Microsoft Windows CE is an operating system developed by Microsoft for embedded systems. Windows CE is a distinct operating system and kernel, rather than a trimmed-down version of desktop Windows...
Kernel or NK ("New Kernel") as it was then called.
Early History – 1980s
Microsoft C (MSC) has a long history dating back to the 1980s. The first Microsoft C Compilers were made by the same company who made Lattice CLattice C
Lattice C was the first C compiler for MS-DOS on the IBM PC, in 1982. It was ported to many other platforms, such as mainframes , minicomputers , workstations , OS/2, the Commodore Amiga, Atari ST and the Sinclair QL.The compiler was subsequently repackaged by Microsoft under a distribution...
and were rebranded by Microsoft as their own, until MSC 4 was released, which was the first version that Microsoft produced themselves.
In 1987 many developers started switching to Microsoft C, and many more would follow throughout the development of Microsoft Windows to its present state. Products like Clipper and later Clarion emerged that offered easy database application development by using cross language techniques, allowing part of their programs to be compiled with Microsoft C.
1987
C programs had long been linked with modules written in assembly languageAssembly language
An assembly language is a low-level programming language for computers, microprocessors, microcontrollers, and other programmable devices. It implements a symbolic representation of the machine codes and other constants needed to program a given CPU architecture...
. Most C compilers (even current compilers) offer an assembly language pass (that can be tweaked for efficiency then linked to the rest of the program after assembling).
Compilers like Aztec-C converted everything to assembly language as a distinct pass and then assembled the code in a distinct pass, and were noted for their very efficient and small code, but by 1987 the optimizer built into Microsoft C was very good, and only "mission critical" parts of a program were usually considered for rewriting. In fact, C language programming had taken over as the "lowest-level" language, with programming becoming a multi-disciplinary growth industry and projects becoming larger, with programmers writing user interfaces and database interfaces in higher-level languages, and a need had emerged for cross language development that continues to this day.
By 1987, with the release of MSC 5.1, Microsoft offered a cross language development environment for MS DOS. 16 bit binary object code written in assembly language (MASM) and Microsoft's other languages including Quick Basic, Pascal
Pascal (programming language)
Pascal is an influential imperative and procedural programming language, designed in 1968/9 and published in 1970 by Niklaus Wirth as a small and efficient language intended to encourage good programming practices using structured programming and data structuring.A derivative known as Object Pascal...
, and Fortran
Fortran
Fortran is a general-purpose, procedural, imperative programming language that is especially suited to numeric computation and scientific computing...
could be linked together into one program, in a process they called "Mixed Language Programming" and now "InterLanguage Calling". If BASIC
BASIC
BASIC is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use - the name is an acronym from Beginner's All-purpose Symbolic Instruction Code....
was used in this mix, the main program needed to be in BASIC to support the internal run-time system
Run-time system
A run-time system is a software component designed to support the execution of computer programs written in some computer language...
that compiled BASIC required for garbage collection and its other managed operations that simulated a BASIC interpreter
Interpreter (computing)
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...
like QBasic
QBasic
QBasic is an IDE and interpreter for a variant of the BASIC programming language which is based on QuickBASIC. Code entered into the IDE is compiled to an intermediate form, and this intermediate form is immediately interpreted on demand within the IDE. It can run under nearly all versions of DOS...
in MS DOS.
The calling convention
Calling convention
In computer science, a calling convention is a scheme for how subroutines receive parameters from their caller and how they return a result; calling conventions can differ in:...
for C code in particular was to pass parameters in "reverse order" on the stack
Call stack
In computer science, a call stack is a stack data structure that stores information about the active subroutines of a computer program. This kind of stack is also known as an execution stack, control stack, run-time stack, or machine stack, and is often shortened to just "the stack"...
and return values on the stack rather than in a processor register
Processor register
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are addressed by mechanisms other than main memory and can be accessed more quickly...
. There were other programming rules to make all the languages work together, but this particular rule persisted through the cross language development that continued throughout Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
16 and 32 bit versions and in the development of programs for OS 2, and which persists to this day. It is known as the Pascal calling convention.
Another type of cross compilation that Microsoft C was used for during this time was in retail applications that require handheld device
Handheld device
A mobile device is a small, hand-held computing device, typically having a display screen with touch input and/or a miniature keyboard and less than . Early pocket sized ones were joined in the late 2000s by larger but otherwise similar tablet computers...
s like the Symbol Technologies
Symbol Technologies
Symbol Technologies is a manufacturer and worldwide supplier of mobile data capture and delivery equipment. The company specializes in barcode scanners, mobile computers, RFID systems and Wireless LAN infrastructure. Symbol Technologies is a wholly owned subsidiary of Motorola, and headquartered in...
PDT3100 (used to take inventory
Inventory
Inventory means a list compiled for some formal purpose, such as the details of an estate going to probate, or the contents of a house let furnished. This remains the prime meaning in British English...
), which provided a link library targeted at an 8088
Intel 8088
The Intel 8088 microprocessor was a variant of the Intel 8086 and was introduced on July 1, 1979. It had an 8-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and the one megabyte address range were unchanged, however...
based barcode reader
Barcode reader
A barcode reader is an electronic device for reading printed barcodes. Like a flatbed scanner, it consists of a light source, a lens and a light sensor translating optical impulses into electrical ones...
. The application was built on the host computer then transferred to the handheld device (via a serial cable
Serial cable
A serial cable is a cable that can be used to transfer information between two devices using serial communication. The form of connectors depends on the particular PHY used...
) where it was run, similar to what is done today for that same market using Windows Mobile
Windows Mobile
Windows Mobile is a mobile operating system developed by Microsoft that was used in smartphones and Pocket PCs, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone, which does not run Windows Mobile software.Windows Mobile is...
by companies like Motorola
Motorola
Motorola, Inc. was an American multinational telecommunications company based in Schaumburg, Illinois, which was eventually divided into two independent public companies, Motorola Mobility and Motorola Solutions on January 4, 2011, after losing $4.3 billion from 2007 to 2009...
, who bought Symbol.
Early 1990s
Throughout the 1990s and beginning with MSC 6 (their first ANSI CANSI C
ANSI C refers to the family of successive standards published by the American National Standards Institute for the C programming language. Software developers writing in C are encouraged to conform to the standards, as doing so aids portability between compilers.-History and outlook:The first...
compliant compiler) Microsoft re-focused their C compilers on the emerging Windows market, and also on OS 2 and in the development of GUI
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
programs. Mixed language compatibility remained through MSC 6 on the MS DOS side, but the API for Microsoft Windows 3.0 and 3.1 was written in MSC 6. MSC 6 was also extended to provide support for 32-bit assemblies and support for the emerging Windows for Workgroups and Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
which would form the foundation for Windows XP
Windows XP
Windows XP is an operating system produced by Microsoft for use on personal computers, including home and business desktops, laptops and media centers. First released to computer manufacturers on August 24, 2001, it is the second most popular version of Windows, based on installed user base...
. A programming practice called a thunk
Thunk (compatibility mapping)
Thunk refers to the creation of a 16-bit virtual DOS machine within a 32-bit operating platform so that there is backward compatibility for applications using older code or system calls.-OS/2 & Windows 16-bit address hack:...
was introduced to allow passing between 16 and 32 bit programs that took advantage of runtime binding (dynamic linking) rather than the static binding that was favoured in monolithic
Monolithic system
Monolithic system can have different meanings in the contexts of computer software and hardware.-In software:A software system is called "monolithic" if it has a monolithic architecture, in which functionally distinguishable aspects , are not architecturally separate components but are...
16 bit MS DOS applications. Static binding is still favoured by some native code developers but does not generally provide the degree of code reuse
Code reuse
Code reuse, also called software reuse, is the use of existing software, or software knowledge, to build new software.-Overview:Ad hoc code reuse has been practiced from the earliest days of programming. Programmers have always reused sections of code, templates, functions, and procedures...
required by newer best practices like the Capability Maturity Model
Capability Maturity Model
The Capability Maturity Model is a development model that was created after study of data collected from organizations that contracted with the U.S. Department of Defense, who funded the research. This model became the foundation from which CMU created the Software Engineering Institute...
(CMM).
MS DOS support was still provided with the release of Microsoft's first C++ Compiler, MSC 7, which was backwardly compatible with the C programming language and MS DOS and supported both 16 bit and 32 bit code generation.
MSC took over where Aztec C86 left off. The market share for C compilers had turned to cross compilers which took advantage of the latest and greatest Windows features, offered C and C++ in a single bundle, and still supported MS DOS systems that were already a decade old, and the smaller companies that produced compilers like Aztec C could no longer compete and either turned to niche markets like embedded systems or disappeared.
MS DOS and 16 bit code generation support continued until MSC 8.00c which was bundled with Microsoft C++ and Microsoft Application Studio 1.5, the forerunner of Microsoft Visual Studio
Microsoft Visual Studio
Microsoft Visual Studio is an integrated development environment from Microsoft. It is used to develop console and graphical user interface applications along with Windows Forms applications, web sites, web applications, and web services in both native code together with managed code for all...
which is the cross development environment that Microsoft provide today.
Late 1990s
MSC 12 was released with Microsoft Visual Studio 6 and no longer provided support for MS DOS 16 bit binaries, instead providing support for 32 bit console applications, but provided support for Windows 95Windows 95
Windows 95 is a consumer-oriented graphical user interface-based operating system. It was released on August 24, 1995 by Microsoft, and was a significant progression from the company's previous Windows products...
and Windows 98
Windows 98
Windows 98 is a graphical operating system by Microsoft. It is the second major release in the Windows 9x line of operating systems. It was released to manufacturing on 15 May 1998 and to retail on 25 June 1998. Windows 98 is the successor to Windows 95. Like its predecessor, it is a hybrid...
code generation as well as for Windows NT
Windows NT
Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...
. Link libraries were available for other processors that ran Microsoft Windows; a practice that Microsoft continues to this day.
MSC 13 was released with Visual Studio 2003, and MSC 14 was released with Visual Studio 2005, both of which still produce code for older systems like Windows 95, but which will produce code for several target platforms including the mobile market and the ARM architecture
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
.
.NET and beyond
In 2001 Microsoft developed the Common Language RuntimeCommon Language Runtime
The Common Language Runtime is the virtual machine component of Microsoft's .NET framework and is responsible for managing the execution of .NET programs. In a process known as just-in-time compilation, the CLR compiles the intermediate language code known as CIL into the machine instructions...
(CLR), which formed the core for their .NET Framework
.NET Framework
The .NET Framework is a software framework that runs primarily on Microsoft Windows. It includes a large library and supports several programming languages which allows language interoperability...
compiler in the Visual Studio IDE. This layer on the operating system which is in the API
Application programming interface
An application programming interface is a source code based specification intended to be used as an interface by software components to communicate with each other...
allows the mixing of development languages compiled across platforms that run the Windows operating system.
The .NET Framework runtime and CLR provide a mapping layer to the core routines for the processor and the devices on the target computer. The command-line C compiler in Visual Studio will compile native code for a variety of processors and can be used to build the core routines themselves.
Microsoft .NET applications for target platforms like Windows Mobile
Windows Mobile
Windows Mobile is a mobile operating system developed by Microsoft that was used in smartphones and Pocket PCs, but by 2011 was rarely supplied on new phones. The last version is "Windows Mobile 6.5.5"; it is superseded by Windows Phone, which does not run Windows Mobile software.Windows Mobile is...
on the ARM architecture
ARM architecture
ARM is a 32-bit reduced instruction set computer instruction set architecture developed by ARM Holdings. It was named the Advanced RISC Machine, and before that, the Acorn RISC Machine. The ARM architecture is the most widely used 32-bit ISA in numbers produced...
cross-compile on Windows machines with a variety of processors and Microsoft also offer emulators and remote deployment environments that require very little configuration, unlike the cross compilers in days gone by or on other platforms.
Runtime libraries, such as Mono
Mono (software)
Mono, pronounced , is a free and open source project led by Xamarin to create an Ecma standard compliant .NET-compatible set of tools including, among others, a C# compiler and a Common Language Runtime....
, provide compatibility for cross-compiled .NET programs to other operating systems, such as Linux
Linux
Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds...
.
Libraries like Qt
Qt (toolkit)
Qt is a cross-platform application framework that is widely used for developing application software with a graphical user interface , and also used for developing non-GUI programs such as command-line tools and consoles for servers...
and its predecessors including XVT
XVT
XVT is a software development environment for building cross-platform GUI applications in C or C++. XVT allows developers to graphically lay out an application's GUI, and provides cross-platform libraries to aid development....
provide source code level cross development capability with other platforms, while still using Microsoft C to build the Windows versions. Other compilers like MinGW
MinGW
MinGW , formerly mingw32, is a native software port of the GNU Compiler Collection and GNU Binutils for use in the development of native Microsoft Windows applications; MinGW can function either as a cross compiler targeting Windows or as a native toolchain run on Windows itself...
have also become popular in this area since they are more directly compatible with the Unixes that comprise the non-Windows side of software development allowing those developers to target all platforms using a familiar build environment.
Free Pascal
Free PascalFree Pascal
Free Pascal Compiler is a free Pascal and Object Pascal compiler.In addition to its own Object Pascal dialect, Free Pascal supports, to varying degrees, the dialects of several other compilers, including those of Turbo Pascal, Delphi, and some historical Macintosh compilers...
was developed from the beginning as a cross compiler. The compiler executable (ppcXXX where XXX is a target architecture) is capable of producing executables (or just object files if no internal linker exists, or even just assembly files if no internal assembler exists) for all OS of the same architecture. For example, ppc386 is capable of producing executables for i386-linux, i386-win32, i386-go32v2 (DOS) and all other OSes (see ). For compiling to another architecture, however, a cross architecture version of the compiler must be built first. The resulting compiler executable would have additional 'ross' before the target architecture in its name. i.e if the compiler is built to target x64, then the executable would be ppcrossx64.
To compile for a chosen architecture-OS, the compiler switch (for the compiler driver fpc) -P and -T can be used. This is also done when cross compiling the compiler itself, but is set via make option CPU_TARGET and OS_TARGET. GNU assembler and linker for the target platform is required if Free Pascal doesn't yet have internal version of the tools for the target platform.
External links
- Cross Compilation Tools – reference for configuring GNU cross compilation tools
- Building Cross Toolchains with gcc is a wiki of other GCC cross-compilation references
- Scratchbox is a toolkit for Linux cross-compilation to ARM and x86 targets
- Grand Unified Builder (GUB) for Linux to cross-compile multiple architectures e.g.:Win32/Mac OS/FreeBSD/Linux used by GNU LilyPondGNU LilyPondGNU LilyPond is a computer program for music engraving. One of LilyPond's major goals is to produce scores that are engraved with traditional layout rules, reflecting the era when scores were engraved by hand....
- Crosstool is a helpful toolchainToolchainIn software, a toolchain is the set of programming tools that are used to create a product...
of scripts, which create a Linux cross-compile environment for the desired architecture, including embedded systems - crosstool-NG is a rewrite of Crosstool and helps building toolchains.
- buildroot is another set of scripts for building a uClibcUClibcIn computing, uClibc is a small C standard library intended for embedded Linux systems. uClibc was created to support uClinux, a version of Linux not requiring a memory management unit and thus suited for microcontrollers .The project lead is Erik Andersen. The other main contributor is Manuel...
-based toolchain, usually for embedded systems. It is utilized by OpenWrtOpenWrtOpenWrt is a Linux distribution primarily targeted at routing on embedded devices. It comprises a set of about 2000 software packages, installed and uninstalled via the opkg package management system. OpenWrt can be configured using the command-line interface of BusyBox ash, or the web interface...
. - ELDK (Embedded Linux Development Kit). Utilized by Das U-BootDas U-BootDas U-Boot is an open source, primary boot loader used in embedded devices. It is available for a number of different computer architectures, including PPC, ARM, MIPS, AVR32, x86, 68k, Nios, and MicroBlaze.- Supported File Systems :...
. - T2 SDE is another set of scripts for building whole Linux Systems based on either GNU libC, uClibc or dietlibc for a variety of architectures
- Cross Linux from Scratch Project
- IBM has a very clear structured tutorial about cross-building a GCC toolchain. Cross-compilation avec GCC 4 sous Windows pour Linux - A tutorial to build a cross-GCC toolchain, but from Windows to Linux, a subject rarely developed