arc: build libgcc in U-Boot

This way we may have very limited set of functions implemented so we
save some space.

Also it allows us to build U-Boot for any ARC core with the same one
toolchain because we don't rely on pre-built libgcc.

For example:
 * we may use little-endian toolchain but build U-Boot for ether
endianess
 * we may use non-multilibbed uClibc toolchain but build U-Boot for
whatever ARC CPU flavour that current GCC supports

Private libgcc built from generic C implementation contributes only 144
bytes to .text section so we don't see significant degradation of size:
--->8---
$ arc-linux-size u-boot.libgcc-prebuilt
   text	   data	    bss	    dec	    hex	filename
 222217	  24912	 214820	 461949	  70c7d	u-boot.libgcc-prebuilt

$ arc-linux-size u-boot.libgcc-private
   text	   data	    bss	    dec	    hex	filename
 222361	  24912	 214820	 462093	  70d0d	u-boot.libgcc-private
--->8---

Also I don't notice visible performance degradation compared to
pre-built libgcc (where at least "*div*" functions are had-written in
assembly) on typical operations of downloading 10Mb uImage over TFTP and
bootm.

Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

1 files changed, 132 insertions, 0 deletions

diff --git a/arch/arc/lib/libgcc2.h b/arch/arc/lib/libgcc2.h
new file mode 100644
index 0000000..8813c3b
--- /dev/null
+++ b/arch/arc/lib/libgcc2.h
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 1989-2013 Free Software Foundation, Inc.
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ASM_LIBGCC_H
+#define __ASM_LIBGCC_H
+
+#define UNITS_PER_WORD 4	/* for ARC */
+#define BITS_PER_UNIT 8		/* for ARC */
+
+#define W_TYPE_SIZE (4 * BITS_PER_UNIT)
+
+#define MIN_UNITS_PER_WORD UNITS_PER_WORD
+
+/* Work out the largest "word" size that we can deal with on this target.  */
+#if MIN_UNITS_PER_WORD > 4
+# define LIBGCC2_MAX_UNITS_PER_WORD 8
+#elif (MIN_UNITS_PER_WORD > 2 \
+       || (MIN_UNITS_PER_WORD > 1 && __SIZEOF_LONG_LONG__ > 4))
+# define LIBGCC2_MAX_UNITS_PER_WORD 4
+#else
+# define LIBGCC2_MAX_UNITS_PER_WORD MIN_UNITS_PER_WORD
+#endif
+
+/* Work out what word size we are using for this compilation.
+   The value can be set on the command line.  */
+#ifndef LIBGCC2_UNITS_PER_WORD
+#define LIBGCC2_UNITS_PER_WORD LIBGCC2_MAX_UNITS_PER_WORD
+#endif
+
+typedef		 int QItype	__attribute__ ((mode (QI)));
+typedef unsigned int UQItype	__attribute__ ((mode (QI)));
+typedef		 int HItype	__attribute__ ((mode (HI)));
+typedef unsigned int UHItype	__attribute__ ((mode (HI)));
+#if MIN_UNITS_PER_WORD > 1
+/* These typedefs are usually forbidden on dsp's with UNITS_PER_WORD 1.  */
+typedef 	 int SItype	__attribute__ ((mode (SI)));
+typedef unsigned int USItype	__attribute__ ((mode (SI)));
+#if __SIZEOF_LONG_LONG__ > 4
+/* These typedefs are usually forbidden on archs with UNITS_PER_WORD 2.  */
+typedef		 int DItype	__attribute__ ((mode (DI)));
+typedef unsigned int UDItype	__attribute__ ((mode (DI)));
+#if MIN_UNITS_PER_WORD > 4
+/* These typedefs are usually forbidden on archs with UNITS_PER_WORD 4.  */
+typedef		 int TItype	__attribute__ ((mode (TI)));
+typedef unsigned int UTItype	__attribute__ ((mode (TI)));
+#endif
+#endif
+#endif
+
+#if LIBGCC2_UNITS_PER_WORD == 8
+#define W_TYPE_SIZE (8 * BITS_PER_UNIT)
+#define Wtype	DItype
+#define UWtype	UDItype
+#define HWtype	DItype
+#define UHWtype	UDItype
+#define DWtype	TItype
+#define UDWtype	UTItype
+#ifdef LIBGCC2_GNU_PREFIX
+#define __NW(a,b)	__gnu_ ## a ## di ## b
+#define __NDW(a,b)	__gnu_ ## a ## ti ## b
+#else
+#define __NW(a,b)	__ ## a ## di ## b
+#define __NDW(a,b)	__ ## a ## ti ## b
+#endif
+#elif LIBGCC2_UNITS_PER_WORD == 4
+#define W_TYPE_SIZE (4 * BITS_PER_UNIT)
+#define Wtype	SItype
+#define UWtype	USItype
+#define HWtype	SItype
+#define UHWtype	USItype
+#define DWtype	DItype
+#define UDWtype	UDItype
+#ifdef LIBGCC2_GNU_PREFIX
+#define __NW(a,b)	__gnu_ ## a ## si ## b
+#define __NDW(a,b)	__gnu_ ## a ## di ## b
+#else
+#define __NW(a,b)	__ ## a ## si ## b
+#define __NDW(a,b)	__ ## a ## di ## b
+#endif
+#elif LIBGCC2_UNITS_PER_WORD == 2
+#define W_TYPE_SIZE (2 * BITS_PER_UNIT)
+#define Wtype	HItype
+#define UWtype	UHItype
+#define HWtype	HItype
+#define UHWtype	UHItype
+#define DWtype	SItype
+#define UDWtype	USItype
+#ifdef LIBGCC2_GNU_PREFIX
+#define __NW(a,b)	__gnu_ ## a ## hi ## b
+#define __NDW(a,b)	__gnu_ ## a ## si ## b
+#else
+#define __NW(a,b)	__ ## a ## hi ## b
+#define __NDW(a,b)	__ ## a ## si ## b
+#endif
+#else
+#define W_TYPE_SIZE BITS_PER_UNIT
+#define Wtype	QItype
+#define UWtype  UQItype
+#define HWtype	QItype
+#define UHWtype	UQItype
+#define DWtype	HItype
+#define UDWtype	UHItype
+#ifdef LIBGCC2_GNU_PREFIX
+#define __NW(a,b)	__gnu_ ## a ## qi ## b
+#define __NDW(a,b)	__gnu_ ## a ## hi ## b
+#else
+#define __NW(a,b)	__ ## a ## qi ## b
+#define __NDW(a,b)	__ ## a ## hi ## b
+#endif
+#endif
+
+typedef int shift_count_type __attribute__((mode (__libgcc_shift_count__)));
+
+#if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__
+	struct DWstruct {Wtype high, low;};
+#else
+	struct DWstruct {Wtype low, high;};
+#endif
+
+/* We need this union to unpack/pack DImode values, since we don't have
+   any arithmetic yet.  Incoming DImode parameters are stored into the
+   `ll' field, and the unpacked result is read from the struct `s'.  */
+
+typedef union {
+	struct DWstruct s;
+	DWtype ll;
+} DWunion;
+
+#endif /* __ASM_LIBGCC_H */