ipxe/src/include/compiler.h

#ifndef COMPILER_H
#define COMPILER_H

/* We export the symbol obj_OBJECT (OBJECT is defined on command-line)
 * as a global symbol, so that the linker can drag in selected object
 * files from the library using -u obj_OBJECT.
 *
 * Not quite sure why cpp requires two levels of macro call in order
 * to actually expand OBJECT...
 */
#undef _H1
#define _H1( x, y ) x ## y
#undef _H2
#define _H2( x, y ) _H1 ( x, y )
#define OBJECT_SYMBOL _H2 ( obj_, OBJECT )
#undef _STR
#define _STR(s) #s
#undef _XSTR
#define _XSTR(s) _STR(s)
#define OBJECT_SYMBOL_STR _XSTR ( OBJECT_SYMBOL )

#ifdef ASSEMBLY

	.globl	OBJECT_SYMBOL
	.equ	OBJECT_SYMBOL, 0

#else /* ASSEMBLY */

__asm__ ( ".globl\t" OBJECT_SYMBOL_STR );
__asm__ ( ".equ\t" OBJECT_SYMBOL_STR ", 0" );

#define REQUIRE_OBJECT(object) \
	__asm__ ( ".equ\tneed_" #object ", obj_" #object );

#define PACKED __attribute__((packed))
#define __unused __attribute__((unused))
#define __used __attribute__((used))

#endif /* ASSEMBLY */

#endif /* COMPILER_H */