Adds support for placing MSP430 code and data into either low memory or high memory.

* msp430/msp430.ld: Delete.
	* msp430/msp430F5438A-l.ld: Delete.
	* msp430/msp430F5438A-s.ld: Delete.
	* msp430/crt_movedata.S: Delete.

	* msp430/Makefile.in (SCRIPTS): Remove msp430.ld.
	(CRT_OBJS): Add crt_move_highdata.o.
	* msp430/memmodel.h (START_CRT_FUNC): New macro.
	(END_CRT_FUNC): New macro.
	(WEAK_DEF): New macro.
	* msp430/crt0.S: Use new macros.
	(move_highdata): New code to initialise the .data section if it is
	held in high memory.

	* msp430/msp430-sim.ld (.data): Add .either.data.
	(.rodata2): Move some read-only data sections here.
	(.text): Add .either.text.
	(.rodata): Add .either.rodata.
	(.bss): Add .either.bss.
	* msp430/msp430xl-sim.ld (MEMORY): Add HIROM.
	(.rodata2): Move some read-only data sections here.
	(.upper.data): New section.  Include notes about how to initialise
	it.

libgloss/msp430/crt0.S

@@ -1,4 +1,4 @@
-/* Copyright (c) 2012-2013 Red Hat, Inc. All rights reserved.
+/* Copyright (c) 2012-2015 Red Hat, Inc. All rights reserved.
 
    This copyrighted material is made available to anyone wishing to use, modify,
    copy, or redistribute it subject to the terms and conditions of the BSD
@@ -14,37 +14,64 @@
 #include "memmodel.h"
 
 ;; The linker links all .crt_* sections in asciibetical order at the
-;; same place.  So, the four digits in .crt_NNNN determine the link
-;; order, so, keep them in sequential order here.  The first two
-;; digits are set here, the second two allow users to insert code
-;; between code fragments here.
+;; same place.  So, the four digits in .crt_NNNN_xxx name created by
+;; the START_CRT_FUNC macro determine the link order, so, keep them
+;; in sequential order here.  The first two digits are set here, the
+;; second two allow users to insert code between code fragments here.
 
 #if L0
 	.section ".resetvec", "a"
 __msp430_resetvec_hook:
-	.word	__start
+	.word	__crt0_start
 
-	.section ".crt_0000init", "ax", @progbits
+	;; Here we provide weak definitions of the symbols used in the
+	;; init_highbss and move_highdata blocks, in case they are not
+	;; provided by the linker script.  They are defined here because
+	;; this block is always included in every executable, and because
+	;; if there were defined in the blocks that need them their values
+	;; would be used without giving the linker script a chance to
+	;; override them.
+	;; 
+	;; The weak definitions are needed if the user targets an MCU
+	;; without high memory - and hence uses a linker script without
+	;; a definition of the .upper.bss or .upper.data sections - and
+	;; they have compiled their code with the -mdata-region=either
+	;; command line option.  That option causes the assembler to
+	;; define the __crt0_move_highdata and/or crt0_init_highbss
+	;; symbols, which in turn forces the inclusion of the
+	;; move_highdata and/or init_highbss blocks in the startup code,
+	;; regardless of the fact that the sections are not present in
+	;; the linker script.
+
+	WEAK_DEF __upper_data_init
+	WEAK_DEF __rom_highdatacopysize
+	WEAK_DEF __high_datastart
+	WEAK_DEF __rom_highdatastart
+	WEAK_DEF __high_bssstart
+	WEAK_DEF __high_bsssize
+
+START_CRT_FUNC 0000 start
 	.refsym	__msp430_resetvec_hook
 #ifdef MINRT
 	.refsym	__crt0_call_just_main
 #else
 	.refsym	__crt0_call_init_then_main
 #endif
-	.global __start
-__start:
 	mov_	#__stack, R1
 
 	;; Disable watchdog timer.
 	MOV	#0x5a80, &0x15C
+END_CRT_FUNC	start
 #endif
 
-#if Lbss
-	.section ".crt_0100bss", "ax", @progbits
 
-	.global __crt0_init_bss
-__crt0_init_bss:	
-	
+#if Lbss
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for initializing
+;; the contents of the .bss section.
+
+START_CRT_FUNC 0100 init_bss
+
 	mov_	#__bssstart, R12
 	clr.w	R13
 	mov.w	#__bsssize, R14
@@ -52,32 +79,41 @@ __crt0_init_bss:
 	clr.w	R15		; We assume that __bsssize is never > 64M
 #endif
 	call_	#memset
-#endif
+
+END_CRT_FUNC	init_bss
+#endif /* Lbss */
+
 
 #ifdef __MSP430X_LARGE__
 #if Lhigh_bss
-;;  Note - this section is only included in the
-;;  startup code of the application if it is needed.
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for initializing
+;; the contents of the .upper.bss section.
 
-	.section ".crt_0150high_bss", "ax", @progbits
+START_CRT_FUNC 0200 init_highbss
 	
-	.global __crt0_init_high_bss
-__crt0_init_high_bss:
-	
-	mov_	#llo(__high_bssstart), R12
-	mov_	#lhi(__high_bssstart), R13
-	mov.w	#llo(__high_bsssize), R14
-	mov.w	#lhi(__high_bsssize), R15	
+	mov_	#__high_bssstart, R12
+	mov.w	#0, R13
+	mov_	#__high_bsssize, R14
+	;; If __high_bsssize is zero then skip the call to memset.
+	;; This can happen if all of the bss data was placed into .either.bss.
+	cmp.w	#0, R14
+	jeq	1f
 	call_	#memset
+1:
+END_CRT_FUNC	init_highbss
 #endif /* Lhigh_bss */
 #endif /* __MSP430X_LARGE__ */
 
-#if Lmovedata
-	.section ".crt_0200movedata", "ax", @progbits
 
-	.global __crt0_movedata
-__crt0_movedata:	
-	
+#if Lmovedata
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for copying the
+;; contents of the .data section from its load address (in ROM) to
+;; its run-time address (in RAM).
+
+START_CRT_FUNC 0300 movedata
+
 	mov_	#__datastart, R12
 	mov_	#__romdatastart, R13
 
@@ -85,44 +121,104 @@ __crt0_movedata:
 	cmp_	R12, R13
 	jeq	1f
 
-	mov.w	#__romdatacopysize, R14
-#ifdef __MSP430X_LARGE__
-	clr.w	R15		; We assume that __romdatacopysize is never > 64M
-#endif
+	mov_	#__romdatacopysize, R14
+
 	call_	#memmove
-1:	
-#endif
+1:
+END_CRT_FUNC	movedata
+#endif /* Lmovedata  */
+
+
+#ifdef __MSP430X_LARGE__
+#if Lmove_highdata
+;; Note - this section is only included in the startup code of the application
+;; if it is needed.  It is responsible either for making sure that the
+;; contents of the .upper.data section have their correct startup values.
+;; If a copy of the .upper.data section is stored in ROM then this means
+;; copying the contents into HIFRAM.  If a copy of .upper.data is stored in a
+;; shadow section in HIFRAM then this means copying from the shadow section
+;; into the real section.
+
+START_CRT_FUNC 0400 move_highdata
+	;;  __rom_highdatacopysize may be zero.  Test this first because
+	;; its value may come from the weak definitions above and we do
+	;; not want to access the memory at address 0 pointed to by the
+	;; weak definition of __upper_data_init.
+	mov.w	#__rom_highdatacopysize, R14
+	cmp.w	#0, R14
+	jeq	3f
+
+	/* Test our status word.  */
+	cmpx.w  #0, &__upper_data_init
+	jeq	1f
+	/* Status word is non-zero - copy from shadow into upper.  */
+	mov_	#__high_datastart, R12
+	mov_	#__rom_highdatastart, R13
+	jmp	2f
+
+1:	/* Status word is zero.  Copy from upper to shadow and change status word.  */
+	movx.w  #1, &__upper_data_init
+	mov_	#__rom_highdatastart, R12
+	mov_	#__high_datastart, R13
+
+2:	;; __rom_highdatacopysize may be zero.  memmove should cope.
+	mov.w	#__rom_highdatacopysize, R14
+
+	call_	#memmove
+3:
+END_CRT_FUNC	move_highdata
+#endif /* Lmove_highdata */
+#endif /* __MSP430X_LARGE__ */
+
 
 #if Lmain_minrt
-	.section ".crt_0300main", "ax", @progbits
-	.global	__crt0_call_just_main
-__crt0_call_just_main:
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for just calling
+;; main.  No initialization code is called first, and main is not
+;; expected to return.
+
+START_CRT_FUNC 0600 call_just_main
+
 	clr.w	R12		; Set argc == 0
 	call_	#main
-#endif
+END_CRT_FUNC	call_just_main
+#endif /* Lmain_minrt */
+
 
 #if Lmain
-	.section ".crt_0300main", "ax", @progbits
-	.global	__crt0_call_init_then_main
-__crt0_call_init_then_main:
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for calling the
+;; initialization code - constructors, etc - and then main.  If main
+;; returns then the following section should be present to catch it.
+
+START_CRT_FUNC 0700 call_init_then_main
+
 	call_	#__msp430_init
 
 	clr.w	R12		; Set argc == 0
 	call_	#main
-#endif
+
+END_CRT_FUNC	call_init_then_main
+#endif /* Lmain */
+
 
 #if Lcallexit
-	.section ".crt_0400main_exit", "ax", @progbits
-	.global	__crt0_call_exit
-__crt0_call_exit:
+;; Note - this section is only included in the startup code of the
+;; application if it is needed.  It is responsible for calling exit
+;; once main has finished.
+
+START_CRT_FUNC 0800 call_exit
+
 	call_	#_exit
-#endif
+
+END_CRT_FUNC	call_exit
+#endif /* Lcallexit  */
 
 ;----------------------------------------
 
 #ifndef MINRT
 #if L0
-	.section ".crt_0500main_init", "ax", @progbits
+	.section ".crt_0900main_init", "ax", @progbits
 	.global	_msp430_run_init_array
 	.type	_msp430_run_init_array,@function
 _msp430_run_init_array:
@@ -172,4 +268,4 @@ __msp430_fini:
 	call_	#_msp430_run_fini_array
 	
 #endif
-#endif
+#endif /* not MINRT */