[PATCH 2/3] arc: Use new definitions for optional ARC CPU features in libgloss

[Anton Kolesov <Anton dot Kolesov at synopsys dot com>]

This is similar to commit 06537f05d4b6a0d2db01c6afda1d2a0ea2588126 to the
newlib for ARC.

GCC for ARC has been updated to provide consistent naming of preprocessor
definitions for different optional architecture features:

    * __ARC_BARREL_SHIFTER__ instead of __Xbarrel_shifter for
      -mbarrel-shifter
    * __ARCEM__ instead of __EM__ for ARC EM cores
    * __ARCHS__ instead of __HS__ for ARC HS cores
    * etc (not used in libgloss)

This patch updates crt0.S for ARC to use new definitions instead of a
deprecated ones. To ensure compatibility with older compiler new definitions
are also defined in crt0.S if needed, based on presence of deprecated
preprocessor definitions.

libgloss/ChangeLog

2016-04-29  Anton Kolesov  <Anton.Kolesov@synopsys.com>

	* arc/crt0.S: Use new GCC defines to detect processor features.

Signed-off-by: Anton Kolesov <Anton.Kolesov@synopsys.com>
---
 libgloss/arc/crt0.S | 35 +++++++++++++++++++++++++----------
 1 file changed, 25 insertions(+), 10 deletions(-)

diff --git a/libgloss/arc/crt0.S b/libgloss/arc/crt0.S
index e4a15eb..fdcdefa 100644
--- a/libgloss/arc/crt0.S
+++ b/libgloss/arc/crt0.S
@@ -1,5 +1,5 @@
 /*
-   Copyright (c) 2015, Synopsys, Inc. All rights reserved.
+   Copyright (c) 2015-2016, Synopsys, Inc. All rights reserved.
 
    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions are met:
@@ -41,10 +41,25 @@
    the initialization code.
 */
 
+/* Compatibility with older ARC GCC, that doesn't provide some of the
+   preprocessor defines used by newlib and libgloss for ARC.  */
+#if defined (__Xbarrel_shifter) && !defined (__ARC_BARREL_SHIFTER__)
+#define __ARC_BARREL_SHIFTER__ 1
+#endif
+
+#if defined (__EM__) && !defined (__ARCEM__)
+#define __ARCEM__ 1
+#endif
+
+#if defined (__HS__) && !defined (__ARCHS__)
+#define __ARCHS__ 1
+#endif
+
+
 	.file	"crt0.S"
 	.extern main
 
-#if defined (__EM__) || defined (__HS__)
+#if defined (__ARCEM__) || defined (__ARCHS__)
 	.section .ivt, "a", @progbits
 
 ; handler's name,          type,    number,name,   offset in IVT (hex/dec)
@@ -74,7 +89,7 @@
 	.section .text.__startup, "ax", @progbits
 #else
 	.text
-#endif
+#endif /* __ARCEM__ || __ARCHS__ */
 
 	.global	__start
 	.type	__start, @function
@@ -111,7 +126,7 @@ __start:
 ;   instruction
 ; - loop body should have at least two instruction words
 __start:
-#if defined (__HS__)
+#if defined (__ARCHS__)
 	; Allow unaligned accesses.
 	lr	r2, [0xA]
 	bset	r2, r2, 19
@@ -159,25 +174,25 @@ __start:
 	mov_s	r0, 1
 	st_s	r0, [r1, 4]		; _GLOBAL_REENT->atexit0._ind
 ; branch to _init
-#if defined (__EM__) || defined (__HS__)
+#if defined (__ARCEM__) || defined (__ARCHS__)
 	jl	@_init
 #else
 	bl	@_init
-#endif
+#endif /* __ARCEM__ || __ARCHS__ */
 	mov_s	r0, r13
 	mov_s	r1, r14
 ; branch to main
-#if defined (__EM__) || defined (__HS__)
+#if defined (__ARCEM__) || defined (__ARCHS__)
 	mov	fp,0			; initialize frame pointer
 	jl	@main
 #else
 	bl.d	@main
 	mov	fp, 0			; initialize frame pointer
-#endif
+#endif /* __ARCEM__ || __ARCHS__ */
 	; r0 contains exit code
 	j	@exit
 
-#if defined (__EM__) || defined (__HS__)
+#if defined (__ARCEM__) || defined (__ARCHS__)
 ; ARCv2 default interrupt routines, defined as weak symbols.
 ; Default implementation halts the core.  To conserve code size those symbols
 ; share a single implementation, however as a downside debugger and
@@ -225,7 +240,7 @@ IRQ_20              :
 	nop
 	b	.Lloop_halt
 	nop
-#endif
+#endif /* __ARCEM__ || __ARCHS__ */
 
 	.section .text._exit_halt,"ax",@progbits
 	.global	 _exit_halt
-- 
2.8.1