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! Copyright (C) 2013 Imagination Technologies Ltd.
! Licensed under the LGPL v2.1 or later, see the file COPYING.LIB in this tarball.
! clone() is even more special than fork() as it mucks with stacks
! and invokes a function in the right context after its all over.
#include <asm/errno.h>
#include <asm/unistd.h>
/* int clone(int (*fn)(void *arg), void *child_stack, int flags, void *arg); */
.text
.global __clone
.type __clone,function
__clone:
! sanity check args
MOV D0Re0, #-EINVAL
CMP D1Ar1, #0
BEQ ___error
CMP D0Ar2, #0
BEQ ___error
! save function pointer
MOV D0FrT, D1Ar1
! do the system call
! get flags
MOV D1Ar1, D1Ar3
! new sp is already in D0Ar2
MOV D1Re0, #__NR_clone
SWITCH #0x440001
CMP D0Re0,#0
! Error on -1
BLT ___error
! If non-zero we are the parent
MOVNE PC, D1RtP
! BRKPNT
! We are the child
! pick the function arg and call address off the stack and execute
MOV D0Ar2, D0FrT
MOV D1Ar1, D0Ar4
MOV D1RtP, PC
ADD D1RtP, D1RtP, #8
MOV PC, D0Ar2
! and we are done, passing the return value through D0Re0
#ifdef __PIC__
B _exit@PLT
#else
B _exit
#endif
___error:
MOV D1Ar1, D0Re0
#ifdef __PIC__
B ___syscall_error@PLT
#else
B ___syscall_error
#endif
.size __clone, .-__clone
.weak _clone
_clone = __clone
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