ld_sysdep.h

它通过提供glibc兼容使得应用程序移植到较小的c 库时相当得容易. 它能够应用到带虚拟存储的Linux和uClinux上.在大多数带MMU部件的平台上为使它更加紧凑,它也能够编译成共享库.uClib

/* CRIS can never use Elf32_Rel relocations. */
#define ELF_USES_RELOCA

/*
 * Get a pointer to the argv array.  On many platforms this can be just
 * the address if the first argument, on other platforms we need to
 * do something a little more subtle here.
 */
#define GET_ARGV(ARGVP, ARGS) ARGVP = ((unsigned long *) ARGS)

/*
 * Initialization sequence for a GOT.
 */
#define INIT_GOT(GOT_BASE,MODULE) 				\
{                               				\
	 GOT_BASE[1] = (unsigned long) MODULE; 			\
	 GOT_BASE[2] = (unsigned long) _dl_linux_resolve; 	\
} 

/*
 * Here is a macro to perform a relocation.  This is only used when
 * bootstrapping the dynamic loader.  RELP is the relocation that we
 * are performing, REL is the pointer to the address we are relocating.
 * SYMBOL is the symbol involved in the relocation, and LOAD is the
 * load address.
 */
#define PERFORM_BOOTSTRAP_RELOC(RELP, REL, SYMBOL, LOAD)			\
	switch (ELF32_R_TYPE((RELP)->r_info)) {           			\
		case R_CRIS_GLOB_DAT:						\
		case R_CRIS_JUMP_SLOT:						\
		case R_CRIS_32:							\
			*REL = SYMBOL;						\
			break;							\
		case R_CRIS_16_PCREL:						\
			*(short *) *REL = SYMBOL + (RELP)->r_addend - *REL - 2;	\
			break;							\
		case R_CRIS_32_PCREL:						\
			*REL = SYMBOL + (RELP)->r_addend - *REL - 4;		\
			break;							\
		case R_CRIS_NONE:						\
			break;							\
		case R_CRIS_RELATIVE:						\
			*REL = (unsigned long) LOAD + (RELP)->r_addend;		\
			break;							\
		default:							\
			_dl_exit(1);						\
			break;							\
	} 

/*
 * Transfer control to the user's application once the dynamic loader
 * is done. This routine has to exit the current function, then call
 * _dl_elf_main.
 */
#define START() __asm__ volatile ("moveq 0,$r8\n\t
								   move $r8,$srp\n\t
								   move.d %1,$sp\n\t
								   jump %0\n\t" : : "r" (_dl_elf_main), "r" (args))

/* Defined some magic numbers that this ld.so should accept. */
#define MAGIC1 EM_CRIS
#undef MAGIC2
#define ELF_TARGET "CRIS"

struct elf_resolve;
extern unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry);

/* Cheap modulo implementation, taken from arm/ld_sysdep.h. */
static inline unsigned long 
cris_mod(unsigned long m, unsigned long p) 
{
	unsigned long i, t, inc;
        
	i = p; 
	t = 0;

        while (!(i & (1 << 31))) {
                i <<= 1;
                t++;
        }
	
        t--;
        
	for (inc = t; inc > 2; inc--) {
                i = p << inc;
		
                if (i & (1 << 31))
                        break;
			
                while (m >= i) {
                        m -= i;
                        i <<= 1;
                        if (i & (1 << 31))
                                break;
                        if (i < p)
                                break;
                }
        }
	
        while (m >= p)
                m -= p;

        return m;
}

#define do_rem(result, n, base) result = cris_mod(n, base);

/* 8192 bytes alignment */
#define PAGE_ALIGN 0xffffe000
#define ADDR_ALIGN 0x1fff
#define OFFS_ALIGN 0xffffe000