1 files changed, 186 insertions, 0 deletions
diff --git a/gcc-4.9/libgcc/config/xtensa/lib2funcs.S b/gcc-4.9/libgcc/config/xtensa/lib2funcs.S
new file mode 100644
index 000000000..3ac8c1da2
--- /dev/null
+++ b/gcc-4.9/libgcc/config/xtensa/lib2funcs.S
@@ -0,0 +1,186 @@
+/* Assembly functions for libgcc2.
+   Copyright (C) 2001-2014 Free Software Foundation, Inc.
+   Contributed by Bob Wilson (bwilson@tensilica.com) at Tensilica.
+
+This file is part of GCC.
+
+GCC 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 3, or (at your option) any later
+version.
+
+GCC 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.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+
+#include "xtensa-config.h"
+
+/* __xtensa_libgcc_window_spill: This function flushes out all but the
+   current register window.  This is used to set up the stack so that
+   arbitrary frames can be accessed.  */
+
+	.align	4
+	.global	__xtensa_libgcc_window_spill
+	.type	__xtensa_libgcc_window_spill,@function
+__xtensa_libgcc_window_spill:
+	entry	sp, 32
+	movi	a2, 0
+	syscall
+	retw
+	.size	__xtensa_libgcc_window_spill, .-__xtensa_libgcc_window_spill
+
+
+/* __xtensa_nonlocal_goto: This code does all the hard work of a
+   nonlocal goto on Xtensa.  It is here in the library to avoid the
+   code size bloat of generating it in-line.  There are two
+   arguments:
+
+	a2 = frame pointer for the procedure containing the label
+	a3 = goto handler address
+
+  This function never returns to its caller but instead goes directly
+  to the address of the specified goto handler.  */
+
+	.align	4
+	.global	__xtensa_nonlocal_goto
+	.type	__xtensa_nonlocal_goto,@function
+__xtensa_nonlocal_goto:
+	entry	sp, 32
+
+	/* Flush registers.  */
+	mov	a5, a2
+	movi	a2, 0
+	syscall
+	mov	a2, a5
+
+	/* Because the save area for a0-a3 is stored one frame below
+	   the one identified by a2, the only way to restore those
+	   registers is to unwind the stack.  If alloca() were never
+	   called, we could just unwind until finding the sp value
+	   matching a2.  However, a2 is a frame pointer, not a stack
+	   pointer, and may not be encountered during the unwinding.
+	   The solution is to unwind until going _past_ the value
+	   given by a2.  This involves keeping three stack pointer
+	   values during the unwinding:
+
+		next = sp of frame N-1
+		cur = sp of frame N
+		prev = sp of frame N+1
+
+	   When next > a2, the desired save area is stored relative
+	   to prev.  At this point, cur will be the same as a2
+	   except in the alloca() case.
+
+	   Besides finding the values to be restored to a0-a3, we also
+	   need to find the current window size for the target
+	   function.  This can be extracted from the high bits of the
+	   return address, initially in a0.  As the unwinding
+	   proceeds, the window size is taken from the value of a0
+	   saved _two_ frames below the current frame.  */
+
+	addi	a5, sp, -16	/* a5 = prev - save area */
+	l32i	a6, a5, 4
+	addi	a6, a6, -16	/* a6 = cur - save area */
+	mov	a8, a0		/* a8 = return address (for window size) */
+	j	.Lfirstframe
+
+.Lnextframe:
+	l32i	a8, a5, 0	/* next return address (for window size) */
+	mov	a5, a6		/* advance prev */
+	addi	a6, a7, -16	/* advance cur */
+.Lfirstframe:
+	l32i	a7, a6, 4	/* a7 = next */
+	bgeu	a2, a7, .Lnextframe
+
+	/* At this point, prev (a5) points to the save area with the saved
+	   values of a0-a3.  Copy those values into the save area at the
+	   current sp so they will be reloaded when the return from this
+	   function underflows.  We don't have to worry about exceptions
+	   while updating the current save area, because the windows have
+	   already been flushed.  */
+
+	addi	a4, sp, -16	/* a4 = save area of this function */
+	l32i	a6, a5, 0
+	l32i	a7, a5, 4
+	s32i	a6, a4, 0
+	s32i	a7, a4, 4
+	l32i	a6, a5, 8
+	l32i	a7, a5, 12
+	s32i	a6, a4, 8
+	s32i	a7, a4, 12
+
+	/* Set return address to goto handler.  Use the window size bits
+	   from the return address two frames below the target.  */
+	extui	a8, a8, 30, 2	/* get window size from return addr. */
+	slli	a3, a3, 2	/* get goto handler addr. << 2 */
+	ssai	2
+	src	a0, a8, a3	/* combine them with a funnel shift */
+
+	retw
+	.size	__xtensa_nonlocal_goto, .-__xtensa_nonlocal_goto
+
+
+/* __xtensa_sync_caches: This function is called after writing a trampoline
+   on the stack to force all the data writes to memory and invalidate the
+   instruction cache. a2 is the address of the new trampoline.
+
+   After the trampoline data is written out, it must be flushed out of
+   the data cache into memory.  We use DHWB in case we have a writeback
+   cache.  At least one DHWB instruction is needed for each data cache
+   line which may be touched by the trampoline.  An ISYNC instruction
+   must follow the DHWBs.
+
+   We have to flush the i-cache to make sure that the new values get used.
+   At least one IHI instruction is needed for each i-cache line which may
+   be touched by the trampoline.  An ISYNC instruction is also needed to
+   make sure that the modified instructions are loaded into the instruction
+   fetch buffer.  */
+
+/* Use the maximum trampoline size.  Flushing a bit extra is OK.  */
+#define TRAMPOLINE_SIZE 60
+
+	.text
+	.align	4
+	.global	__xtensa_sync_caches
+	.type	__xtensa_sync_caches,@function
+__xtensa_sync_caches:
+	entry 	sp, 32
+#if XCHAL_DCACHE_SIZE > 0
+	/* Flush the trampoline from the data cache.  */
+	extui	a4, a2, 0, XCHAL_DCACHE_LINEWIDTH
+	addi	a4, a4, TRAMPOLINE_SIZE
+	addi	a4, a4, (1 << XCHAL_DCACHE_LINEWIDTH) - 1
+	srli	a4, a4, XCHAL_DCACHE_LINEWIDTH
+	mov	a3, a2
+.Ldcache_loop:
+	dhwb	a3, 0
+	addi	a3, a3, (1 << XCHAL_DCACHE_LINEWIDTH)
+	addi	a4, a4, -1
+	bnez	a4, .Ldcache_loop
+	isync
+#endif
+#if XCHAL_ICACHE_SIZE > 0
+	/* Invalidate the corresponding lines in the instruction cache.  */
+	extui	a4, a2, 0, XCHAL_ICACHE_LINEWIDTH
+	addi	a4, a4, TRAMPOLINE_SIZE
+	addi	a4, a4, (1 << XCHAL_ICACHE_LINEWIDTH) - 1
+	srli	a4, a4, XCHAL_ICACHE_LINEWIDTH
+.Licache_loop:
+	ihi	a2, 0
+	addi	a2, a2, (1 << XCHAL_ICACHE_LINEWIDTH)
+	addi	a4, a4, -1
+	bnez	a4, .Licache_loop
+#endif
+	isync
+	retw
+	.size	__xtensa_sync_caches, .-__xtensa_sync_caches