* darwin-tramp.asm: New file, implements __trampoline_setup.

From-SVN: r47760

gcc/config/rs6000/darwin-tramp.asm

+/*  Special support for trampolines
+ *
+ *   Copyright (C) 1996, 1997, 2000 Free Software Foundation, Inc.
+ *   Written By Michael Meissner
+ * 
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ * 
+ * In addition to the permissions in the GNU General Public License, the
+ * Free Software Foundation gives you unlimited permission to link the
+ * compiled version of this file with other programs, and to distribute
+ * those programs without any restriction coming from the use of this
+ * file.  (The General Public License restrictions do apply in other
+ * respects; for example, they cover modification of the file, and
+ * distribution when not linked into another program.)
+ * 
+ * This file is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ * 
+ *  As a special exception, if you link this library with files
+ *  compiled with GCC to produce an executable, this does not cause the
+ *  resulting executable to be covered by the GNU General Public License.
+ *  This exception does not however invalidate any other reasons why the
+ *  executable file might be covered by the GNU General Public License.
+ */ 
+
+/* Set up trampolines. */
+
+.text
+	.align	2
+Ltrampoline_initial:
+	mflr	r0
+	bl	1f
+Lfunc = .-Ltrampoline_initial
+	.long	0		/* will be replaced with function address */
+Lchain = .-Ltrampoline_initial
+	.long	0		/* will be replaced with static chain */
+1:	mflr	r11
+	lwz	r12,0(r11)	/* function address */
+	mtlr	r0
+	mtctr	r12
+	lwz	r11,4(r11)	/* static chain */
+	bctr
+
+trampoline_size = .-Ltrampoline_initial
+
+/* R3 = stack address to store trampoline */
+/* R4 = length of trampoline area */
+/* R5 = function address */
+/* R6 = static chain */
+
+	.globl ___trampoline_setup
+___trampoline_setup:
+	mflr	r0		/* save return address */
+        bcl 20,31,LCF0		/* load up __trampoline_initial into r7 */
+LCF0:
+        mflr	r11
+        addi	r7,r11,ha16(LTRAMP-LCF0)
+	lwz	r7,lo16(LTRAMP-LCF0)(r7)
+	subi	r7,r7,4
+	li	r8,trampoline_size	/* verify trampoline big enough */
+	cmpw	cr1,r8,r4
+	srwi	r4,r4,2		/* # words to move */
+	addi	r9,r3,-4	/* adjust pointer for lwzu */
+	mtctr	r4
+	blt	cr1,Labort
+
+	mtlr	r0
+
+	/* Copy the instructions to the stack */
+Lmove:
+	lwzu	r10,4(r7)
+	stwu	r10,4(r9)
+	bdnz	Lmove
+
+	/* Store correct function and static chain */
+	stw	r5,Lfunc(r3)
+	stw	r6,Lchain(r3)
+
+	/* Now flush both caches */
+	mtctr	r4
+Lcache:
+	icbi	0,r3
+	dcbf	0,r3
+	addi	r3,r3,4
+	bdnz	Lcache
+
+	/* Finally synchronize things & return */
+	sync
+	isync
+	blr
+
+Labort:
+#ifdef __DYNAMIC__
+	bl	L_abort$stub
+.data
+.picsymbol_stub
+L_abort$stub:
+        .indirect_symbol _abort
+        mflr r0
+        bcl 20,31,L0$_abort
+L0$_abort:
+        mflr r11
+        addis r11,r11,ha16(L_abort$lazy_ptr-L0$_abort)
+        mtlr r0
+        lwz r12,lo16(L_abort$lazy_ptr-L0$_abort)(r11)
+        mtctr r12
+        addi r11,r11,lo16(L_abort$lazy_ptr-L0$_abort)
+        bctr
+.data
+.lazy_symbol_pointer
+L_abort$lazy_ptr:
+        .indirect_symbol _abort
+        .long dyld_stub_binding_helper
+#else
+	bl	_abort
+#endif
+.data
+	.align 2
+LTRAMP:
+	.long Ltrampoline_initial
+