resolve.s

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

/*
 * This function is _not_ called directly.  It is jumped to (so no return
 * address is on the stack) when attempting to use a symbol that has not yet
 * been resolved.  The first time a jump symbol (such as a function call inside
 * a shared library) is used (before it gets resolved) it will jump here to
 * _dl_linux_resolve.  When we get called the stack looks like this:
 *	reloc_entry
 *	tpnt
 *
 * This function saves all the registers, puts a copy of reloc_entry and tpnt
 * on the stack (as function arguments) then make the function call
 * _dl_linux_resolver(tpnt, reloc_entry).  _dl_linux_resolver() figures out
 * where the jump symbol is _really_ supposed to have jumped to and returns
 * that to us.  Once we have that, we overwrite tpnt with this fixed up
 * address. We then clean up after ourselves, put all the registers back how we
 * found them, then we jump to the fixed up address, which is where the jump
 * symbol that got us here really wanted to jump to in the first place.  
 *  -Erik Andersen
 */

#define sl r10
#define fp r11
#define ip r12

.text
.globl _dl_linux_resolve
.type _dl_linux_resolve,%function
.align 4;

_dl_linux_resolve:
	stmdb sp!, {r0, r1, r2, r3, sl, fp}
	sub r1, ip, lr
	sub r1, r1, #4
	add r1, r1, r1
	ldr r0, [lr, #-4]
	mov r3,r0

	bl _dl_linux_resolver

	mov ip, r0
	ldmia sp!, {r0, r1, r2, r3, sl, fp, lr}
	mov pc,ip
.size _dl_linux_resolve, .-_dl_linux_resolve