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* [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment.
@ 2019-07-19 13:22 alfedotov
  2019-07-19 13:22 ` [PATCH v2 2/2] [Arm] Stack Pointer and Stack Limit initialization refactored alfedotov
  2019-07-22  8:52 ` [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment Corinna Vinschen
  0 siblings, 2 replies; 3+ messages in thread
From: alfedotov @ 2019-07-19 13:22 UTC (permalink / raw)
  To: Richard.Earnshaw, newlib; +Cc: Alexander Fedotov

From: Alexander Fedotov <alfedotov@gmail.com>

---
 libgloss/arm/crt0.S        | 137 +++++++++++++++++++------------------
 newlib/libc/sys/arm/crt0.S |  20 +++---
 2 files changed, 80 insertions(+), 77 deletions(-)

diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index c708f63d8..f21add8bc 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -68,8 +68,10 @@
 #endif
 .endm
 
+/*******************************************************************************
+* Main library startup code.
+*******************************************************************************/
 	.align 	0
-
 	FUNC_START	_mainCRTStartup
 	FUNC_START	_start
 #if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
@@ -90,14 +92,14 @@
 #endif
 #endif
 
-/* Start by setting up a stack */
+/* Start by setting up a stack.  */
 #ifdef ARM_RDP_MONITOR
-	/*  Issue Demon SWI to read stack info */
-	swi	SWI_GetEnv	/*  Returns command line in r0 */
-	mov	sp,r1		/*  and the highest memory address in r1 */
+	/*  Issue Demon SWI to read stack info.  */
+	swi	SWI_GetEnv	/*  Returns command line in r0.  */
+	mov	sp,r1		/*  and the highest memory address in r1.  */
 
-	/*  stack limit is at end of data */
-	/*  allow slop for stack overflow handling and small frames */
+	/*  Stack limit is at end of data.  */
+	/*  Allow slop for stack overflow handling and small frames.  */
 #ifdef THUMB1_ONLY
 	ldr	r0, .LC2
 	adds	r0, #128
@@ -109,19 +111,19 @@
 #endif
 #else
 #ifdef ARM_RDI_MONITOR
-	/*  Issue Angel SWI to read stack info */
+	/*  Issue Angel SWI to read stack info.  */
 	movs	r0, #AngelSWI_Reason_HeapInfo
-	adr	r1, .LC0	/*  point at ptr to 4 words to receive data */
+	adr	r1, .LC0	/*  Point at ptr to 4 words to receive data.  */
 #ifdef THUMB_VXM
 	bkpt	AngelSWI
 #elif defined(__thumb2__)
-	/*  We are in thumb mode for startup on armv7 architectures. */
+	/*  We are in thumb mode for startup on armv7 architectures.  */
 	AngelSWIAsm (AngelSWI)
 #else
-	/*  We are always in ARM mode for startup on pre armv7 archs. */
+	/*  We are always in ARM mode for startup on pre armv7 archs.  */
 	AngelSWIAsm (AngelSWI_ARM)
 #endif
-	ldr	r0, .LC0	/*  point at values read */
+	ldr	r0, .LC0	/*  Point at values read.  */
 
 	/* Set __heap_limit.  */
 	ldr     r1, [r0, #4]
@@ -148,14 +150,15 @@
 	      to skip setting sp/sl to 0 here.
 	    - Considering M-profile processors, We might want to initialize
 	      sp by the first entry of vector table and return 0 to SYS_HEAPINFO
-	      semihosting call, which will be skipped here. */
+	      semihosting call, which will be skipped here.  */
 	cmp	r1, #0
 	beq	.LC26
 	mov	sp, r1
 .LC26:
 	cmp	r2, #0
 	beq	.LC27
-	/*  allow slop for stack overflow handling and small frames */
+
+	/*  Allow slop for stack overflow handling and small frames.  */
 #ifdef THUMB1_ONLY
 	adds	r2, #128
 	adds	r2, #128
@@ -163,9 +166,10 @@
 #else
 	add	sl, r2, #256
 #endif
+
 .LC27:
 #else
-	/*  Set up the stack pointer to a fixed value */
+	/*  Set up the stack pointer to a fixed value.  */
 	/*  Changes by toralf:
 	    - Allow linker script to provide stack via __stack symbol - see
 	      defintion of .Lstack
@@ -175,7 +179,7 @@
 	      Loosely based on init.s from ARM/Motorola example code.
               Note: Mode switch via CPSR is not allowed once in non-privileged
 		    mode, so we take care not to enter "User" to set up its sp,
-		    and also skip most operations if already in that mode. */
+		    and also skip most operations if already in that mode.  */
 
 	ldr	r3, .Lstack
 	cmp	r3, #0
@@ -192,42 +196,42 @@
 	/* Note: This 'mov' is essential when starting in User, and ensures we
 		 always get *some* sp value for the initial mode, even if we 
 		 have somehow missed it below (in which case it gets the same
-		 value as FIQ - not ideal, but better than nothing.) */
+		 value as FIQ - not ideal, but better than nothing).  */
 	mov	sp, r3
 #ifdef PREFER_THUMB
 	/* XXX Fill in stack assignments for interrupt modes.  */
 #else
 	mrs	r2, CPSR
-	tst	r2, #0x0F	/* Test mode bits - in User of all are 0 */
-	beq	.LC23		/* "eq" means r2 AND #0x0F is 0 */
-	msr     CPSR_c, #0xD1	/* FIRQ mode, interrupts disabled */
+	tst	r2, #0x0F	/* Test mode bits - in User of all are 0.  */
+	beq	.LC23		/* "eq" means r2 AND #0x0F is 0.  */
+	msr     CPSR_c, #0xD1	/* FIRQ mode, interrupts disabled.  */
 	mov 	sp, r3
-	sub	sl, sp, #0x1000	/* This mode also has its own sl (see below) */
+	sub	sl, sp, #0x1000	/* This mode also has its own sl (see below).  */
 	
 	mov	r3, sl	
-	msr     CPSR_c, #0xD7	/* Abort mode, interrupts disabled */
+	msr     CPSR_c, #0xD7	/* Abort mode, interrupts disabled.  */
 	mov	sp, r3
 	sub	r3, r3, #0x1000
 
-	msr     CPSR_c, #0xDB	/* Undefined mode, interrupts disabled */
+	msr     CPSR_c, #0xDB	/* Undefined mode, interrupts disabled.  */
 	mov	sp, r3
 	sub	r3, r3, #0x1000
 
-	msr     CPSR_c, #0xD2	/* IRQ mode, interrupts disabled */
+	msr     CPSR_c, #0xD2	/* IRQ mode, interrupts disabled.  */
 	mov	sp, r3
 	sub	r3, r3, #0x2000
 		
-	msr     CPSR_c, #0xD3	/* Supervisory mode, interrupts disabled */
+	msr     CPSR_c, #0xD3	/* Supervisory mode, interrupts disabled.  */
 
 	mov	sp, r3
-	sub	r3, r3, #0x8000	/* Min size 32k */
-	bic	r3, r3, #0x00FF	/* Align with current 64k block */
+	sub	r3, r3, #0x8000	/* Min size 32k.  */
+	bic	r3, r3, #0x00FF	/* Align with current 64k block.  */
 	bic	r3, r3, #0xFF00
 
 	str	r3, [r3, #-4]	/* Move value into user mode sp without */ 
-	ldmdb	r3, {sp}^       /* changing modes, via '^' form of ldm */ 
+	ldmdb	r3, {sp}^       /* changing modes, via '^' form of ldm.  */ 
 	orr	r2, r2, #0xC0	/* Back to original mode, presumably SVC, */
-	msr	CPSR_c, r2	/* with FIQ/IRQ disable bits forced to 1 */
+	msr	CPSR_c, r2	/* with FIQ/IRQ disable bits forced to 1.  */
 #endif	
 .LC23:
 	/* Setup a default stack-limit in-case the code has been
@@ -243,24 +247,24 @@
 	subs	r2, r3, r2
 	mov	sl, r2
 #else
-	sub	sl, r3, #64 << 10	/* Still assumes 256bytes below sl */
+	sub	sl, r3, #64 << 10	/* Still assumes 256bytes below sl.  */
 #endif
 #endif
 #endif
 	/* Zero the memory in the .bss section.  */
-	movs 	a2, #0			/* Second arg: fill value */
-	mov	fp, a2			/* Null frame pointer */
-	mov	r7, a2			/* Null frame pointer for Thumb */
+	movs 	a2, #0			/* Second arg: fill value.  */
+	mov	fp, a2			/* Null frame pointer.  */
+	mov	r7, a2			/* Null frame pointer for Thumb.  */
 	
-	ldr	a1, .LC1		/* First arg: start of memory block */
+	ldr	a1, .LC1		/* First arg: start of memory block.  */
 	ldr	a3, .LC2	
-	subs	a3, a3, a1		/* Third arg: length of block */
+	subs	a3, a3, a1		/* Third arg: length of block.  */
 	
 
 #if __thumb__ && !defined(PREFER_THUMB)
-	/* Enter Thumb mode.... */
-	add	a4, pc, #1	/* Get the address of the Thumb block */
-	bx	a4		/* Go there and start Thumb decoding  */
+	/* Enter Thumb mode...  */
+	add	a4, pc, #1	/* Get the address of the Thumb block.  */
+	bx	a4		/* Go there and start Thumb decoding.  */
 
 	.code 16
 	.global __change_mode
@@ -271,9 +275,8 @@ __change_mode:
 	bl	FUNCTION (memset)
 #if !defined (ARM_RDP_MONITOR) && !defined (ARM_RDI_MONITOR)
 /* Changes by toralf: Taken from libgloss/m68k/crt0.S
- * initialize target specific stuff. Only execute these
- * functions it they exist.
- */
+   initialize target specific stuff. Only execute these
+   functions it they exist.  */
 	ldr	r3, .Lhwinit
 	cmp	r3, #0
 	beq	.LC24
@@ -285,24 +288,24 @@ __change_mode:
 	indirect_call r3
 
 .LC25:	
-	movs	r0, #0		/*  no arguments  */
-	movs	r1, #0		/*  no argv either */
+	movs	r0, #0		/* No arguments.  */
+	movs	r1, #0		/* No argv either.  */
 #else
-	/* Need to set up standard file handles */
+	/* Need to set up standard file handles.  */
 	bl	FUNCTION (initialise_monitor_handles)
 	
 #ifdef ARM_RDP_MONITOR
-	swi	SWI_GetEnv	/*  sets r0 to point to the command line */
+	swi	SWI_GetEnv	/* Sets r0 to point to the command line.  */
 	movs	r1, r0
 #else
 	movs	r0, #AngelSWI_Reason_GetCmdLine
-	ldr	r1, .LC30	/*  Space for command line */
+	ldr	r1, .LC30	/* Space for command line.  */
 	AngelSWIAsm (AngelSWI)
 	ldr	r1, .LC30
 	ldr	r1, [r1]
 #endif
-	/*  Parse string at r1 */
-	movs	r0, #0		/*  count of arguments so far */
+	/*  Parse string at r1.  */
+	movs	r0, #0		/* Count of arguments so far.  */
 	/* Push a NULL argument onto the end of the list.  */
 #ifdef __thumb__
 	push	{r0}
@@ -310,7 +313,7 @@ __change_mode:
 	stmfd	sp!, {r0}
 #endif
 .LC10:
-/*  Skip leading blanks */
+/*  Skip leading blanks.  */
 #ifdef __thumb__
 	ldrb	r3, [r1]
 	adds	r1, #1
@@ -322,7 +325,7 @@ __change_mode:
 	cmp	r3, #' '
 	beq	.LC10
 
-/*  See whether we are scanning a string */
+/* See whether we are scanning a string.  */
 	cmp	r3, #'"'
 #ifdef __thumb__
 	beq	.LC20
@@ -333,17 +336,17 @@ __change_mode:
 	b	.LC22
 
 .LC21:
-	movs	r2, #' '	/*  terminator type */
-	subs	r1, r1, #1	/*  adjust back to point at start char */
+	movs	r2, #' '	/* Terminator type.  */
+	subs	r1, r1, #1	/* Adjust back to point at start char.  */
 .LC22:
 #else
 	cmpne	r3, #'\''
 	moveq	r2, r3
-	movne	r2, #' '	/*  terminator type */
-	subne	r1, r1, #1	/*  adjust back to point at start char */
+	movne	r2, #' '	/* Terminator type.  */
+	subne	r1, r1, #1	/* Adjust back to point at start char.  */
 #endif
 
-/*  Stack a pointer to the current argument */
+/*  Stack a pointer to the current argument.  */
 #ifdef __thumb__
 	push	{r1}
 #else
@@ -359,16 +362,16 @@ __change_mode:
 #endif
 	cmp	r3, #0
 	beq	.LC12
-	cmp	r2, r3		/*  reached terminator? */
+	cmp	r2, r3		/* Reached terminator ?  */
 	bne	.LC11
 	movs	r2, #0
 	subs	r3, r1, #1
-	strb	r2, [r3]	/*  terminate the arg string */
+	strb	r2, [r3]	/* Terminate the arg string.  */
 	b	.LC10
 
 .LC12:
-	mov	r1, sp		/*  point at stacked arg pointers */
-	/* We've now got the stacked args in order reverse the */
+	mov	r1, sp		/* Point at stacked arg pointers.  */
+	/* We've now got the stacked args in order, reverse them.  */
 #ifdef __thumb__
 	movs	r2, r0
 	lsls	r2, #2
@@ -390,10 +393,10 @@ __change_mode:
 	bics	r4, r5
 	mov	sp, r4
 #else
-	add	r2, sp, r0, LSL #2	/* End of args */
-	mov	r3, sp			/* Start of args */
+	add	r2, sp, r0, LSL #2	/* End of args.  */
+	mov	r3, sp			/* Start of args.  */
 .LC13:	cmp	r2, r3
-	ldrhi	r4,[r2, #-4]		/* Reverse ends of list */
+	ldrhi	r4,[r2, #-4]		/* Reverse ends of list.  */
 	ldrhi	r5, [r3]
 	strhi	r5, [r2, #-4]!
 	strhi	r4, [r3], #4
@@ -431,7 +434,6 @@ __change_mode:
 
 #if __thumb__ && !defined(PREFER_THUMB)
 	/* Come out of Thumb mode.  This code should be redundant.  */
-
 	mov	a4, pc
 	bx	a4
 
@@ -441,13 +443,12 @@ change_back:
 	/* Halt the execution.  This code should never be executed.  */
 	/* With no debug monitor, this probably aborts (eventually).
 	   With a Demon debug monitor, this halts cleanly.
-	   With an Angel debug monitor, this will report 'Unknown SWI'.	 */
+	   With an Angel debug monitor, this will report 'Unknown SWI'.  */
 	swi	SWI_Exit
 #endif
 	
 	/* For Thumb, constants must be after the code since only 
 	   positive offsets are supported for PC relative addresses.  */
-	
 	.align 0
 .LC0:
 #ifdef ARM_RDI_MONITOR
@@ -457,13 +458,13 @@ change_back:
 	/* Changes by toralf: Provide alternative "stack" variable whose value
 	   may be defined externally; .Lstack will be used instead of .LC0 if
 	   it points to a non-0 value. Also set up references to "hooks" that
-           may be used by the application to provide additional init code. */
-	
+           may be used by the application to provide additional init code.  */
 #ifdef __pe__
 	.word	0x800000
 #else
 	.word	0x80000			/* Top of RAM on the PIE board.  */
 #endif
+
 .Lstack:	
 	.word	__stack
 .Lhwinit:	
@@ -476,7 +477,7 @@ change_back:
 	   runtime (meaning "ignore setting") for the variables, when the user
 	   does not provide the symbols. (The linker uses a weak symbol if,
 	   and only if, a normal version of the same symbol isn't provided
-	   e.g. by a linker script or another object file.) */	
+	   e.g. by a linker script or another object file.)  */
 
 	.weak __stack
 	.weak FUNCTION (hardware_init_hook) 
diff --git a/newlib/libc/sys/arm/crt0.S b/newlib/libc/sys/arm/crt0.S
index 8c9f7be38..3358d7014 100644
--- a/newlib/libc/sys/arm/crt0.S
+++ b/newlib/libc/sys/arm/crt0.S
@@ -50,13 +50,13 @@
 	.global \name
 	.thumb_func
 \name:
-.endm	
+.endm
 #else
 	.code 32
 .macro FUNC_START name
-	.global	\name
+	.global \name
 \name:
-.endm	
+.endm
 #endif
 
 .macro indirect_call reg
@@ -68,8 +68,10 @@
 #endif
 .endm
 
+/*******************************************************************************
+* Main library startup code.
+*******************************************************************************/
 	.align 	0
-
 	FUNC_START	_mainCRTStartup
 	FUNC_START	_start
 #if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
@@ -399,7 +401,7 @@ __change_mode:
 	bl	FUNCTION (_init)
 	movs	r0, r4
 	movs	r1, r5
-#endif	
+#endif
 	bl	FUNCTION (main)
 
 	bl	FUNCTION (exit)		/* Should not return.  */
@@ -415,12 +417,12 @@ change_back:
 	/* Halt the execution.  This code should never be executed.  */
 	/* With no debug monitor, this probably aborts (eventually).
 	   With a Demon debug monitor, this halts cleanly.
-	   With an Angel debug monitor, this will report 'Unknown SWI'.	 */
+	   With an Angel debug monitor, this will report 'Unknown SWI'.  */
 	swi	SWI_Exit
 #endif
 	
 	/* For Thumb, constants must be after the code since only 
-	   positive offsets are supported for PC relative addresses.  */	
+	   positive offsets are supported for PC relative addresses.  */
 	.align 0
 .LC0:
 #ifdef ARM_RDI_MONITOR
@@ -430,7 +432,7 @@ change_back:
 	/* Changes by toralf: Provide alternative "stack" variable whose value
 	   may be defined externally; .Lstack will be used instead of .LC0 if
 	   it points to a non-0 value. Also set up references to "hooks" that
-           may be used by the application to provide additional init code.  */	
+           may be used by the application to provide additional init code.  */
 #ifdef __pe__
 	.word	0x800000
 #else
@@ -449,7 +451,7 @@ change_back:
 	   runtime (meaning "ignore setting") for the variables, when the user
 	   does not provide the symbols. (The linker uses a weak symbol if,
 	   and only if, a normal version of the same symbol isn't provided
-	   e.g. by a linker script or another object file).  */	
+	   e.g. by a linker script or another object file.)  */
 
 	.weak __stack
 	.weak FUNCTION (hardware_init_hook) 
-- 
2.17.1

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [PATCH v2 2/2] [Arm] Stack Pointer and Stack Limit initialization refactored.
  2019-07-19 13:22 [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment alfedotov
@ 2019-07-19 13:22 ` alfedotov
  2019-07-22  8:52 ` [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment Corinna Vinschen
  1 sibling, 0 replies; 3+ messages in thread
From: alfedotov @ 2019-07-19 13:22 UTC (permalink / raw)
  To: Richard.Earnshaw, newlib; +Cc: Alexander Fedotov

From: Alexander Fedotov <alfedotov@gmail.com>

SP initialization changes:
  1. set default value in semihosting case as well
  2. moved existing SP & SL init code for processor modes in separate routine and made it as "hook"
  3. init SP for processor modes in Thumb mode as well

Add new macro FN_RETURN, FN_EH_START and FN_EH_END.
---
 libgloss/arm/arm.h         |  26 ++++
 libgloss/arm/crt0.S        | 281 ++++++++++++++++++++++++++-----------
 newlib/libc/sys/arm/arm.h  |  26 ++++
 newlib/libc/sys/arm/crt0.S | 281 ++++++++++++++++++++++++++-----------
 4 files changed, 444 insertions(+), 170 deletions(-)

diff --git a/libgloss/arm/arm.h b/libgloss/arm/arm.h
index 0489f2d92..10e5b0509 100644
--- a/libgloss/arm/arm.h
+++ b/libgloss/arm/arm.h
@@ -61,4 +61,30 @@
 # define HAVE_CALL_INDIRECT
 #endif
 
+/* A and R profiles (and legacy Arm).
+	Current Program Status Register (CPSR)
+	M[4:0]		Mode bits. M[4] is always 1 for 32-bit modes.
+	T[5]			1: Thumb, 0: ARM instruction set
+	F[6]			1: disables FIQ
+	I[7]			1: disables IRQ
+	A[8]			1: disables imprecise aborts
+	E[9]			0: Little-endian, 1: Big-endian
+	J[24]			1: Jazelle instruction set
+ */
+#define CPSR_M_USR			0x00	/* User mode.  */
+#define CPSR_M_FIQ			0x01	/* Fast Interrupt mode.  */
+#define CPSR_M_IRQ			0x02	/* Interrupt mode.  */
+#define CPSR_M_SVR			0x03	/* Supervisor mode.  */
+#define CPSR_M_MON			0x06	/* Monitor mode.  */
+#define CPSR_M_ABT			0x07	/* Abort mode.  */
+#define CPSR_M_HYP			0x0A	/* Hypervisor mode.  */
+#define CPSR_M_UND			0x0B	/* Undefined mode.  */
+#define CPSR_M_SYS			0x0F	/* System mode.  */
+#define CPSR_M_32BIT		0x10	/* 32-bit mode.  */
+#define CPSR_T_BIT			0x20	/* Thumb bit.  */
+#define CPSR_F_MASK			0x40	/* FIQ bit.  */
+#define CPSR_I_MASK			0x80	/* IRQ bit.  */
+
+#define CPSR_M_MASK			0x0F	/* Mode mask except M[4].  */
+
 #endif /* _LIBGLOSS_ARM_H */
diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index f21add8bc..7b3270c33 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -59,6 +59,21 @@
 .endm
 #endif
 
+/* Annotation for EABI unwinding tables.  */
+.macro FN_EH_START
+#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+	.fnstart
+#endif
+.endm
+
+.macro FN_EH_END
+#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+	/* Protect against unhandled exceptions.  */
+	.cantunwind
+	.fnend
+#endif
+.endm
+
 .macro indirect_call reg
 #ifdef HAVE_CALL_INDIRECT
 	blx \reg
@@ -68,16 +83,170 @@
 #endif
 .endm
 
+/* For armv4t and newer, toolchains will transparently convert
+   'bx lr' to 'mov pc, lr' if needed. GCC has deprecated support
+   for anything older than armv4t, but this should handle that
+   corner case in case anyone needs it anyway.  */
+.macro  FN_RETURN
+#if __ARM_ARCH <= 4 && __ARM_ARCH_ISA_THUMB == 0
+	mov	pc, lr
+#else
+	bx	lr
+#endif
+.endm
+
+
+
+/******************************************************************************
+* User mode only:           This routine makes default target specific Stack
+*   +-----+ <- SL_sys,    Pointer initialization for different processor modes:
+*   |     |    SL_usr     FIQ, Abort, IRQ, Undefined, Supervisor, System (User)
+*   | SYS |               and setups a default Stack Limit in-case the code has
+*   | USR | -=0x10000     been compiled with "-mapcs-stack-check" for FIQ and
+*   |     |               System (User) modes.
+*   |     |
+*   +-----+ <- initial SP,
+*           becomes SP_sys   Hard-wiring SL value is not ideal, since there is
+*           and SL_usr     currently no support for checking that the heap and
+*                          stack have not collided, or that this default 64k is
+* All modes:               is enough for the program being executed. However,
+*   +-----+ <- SL_sys,     it ensures that this simple crt0 world will not
+*   |     |    SL_usr      immediately cause an overflow event.
+*   | SYS |
+*   | USR | -=0x10000        We go through all execution modes and set up SP
+*   |     |                for each of them.
+*   +-----+ <- SP_sys,
+*   |     |    SP_usr      Note:
+*   | SVC | -= 0x8000        Mode switch via CPSR is not allowed once in
+*   |     |                  non-privileged mode, so we take care not to enter
+*   +-----+ <- SP_svc        "User" to set up its sp, and also skip most
+*   |     |                  operations if already in that mode.
+*   | IRQ | -= 0x2000
+*   |     |                Input parameters:
+* ^ +-----+ <- SP_und       - sp - Initialized SP
+* s |     |                 - r2 - May contain SL value from semihosting
+* t | UND | -= 0x1000              SYS_HEAPINFO call
+* a |     |                Scratch registers:
+* c +-----+ <- SP_und       - r1 - new value of CPSR
+* k |     |                 - r2 - intermediate value (in standalone mode)
+*   | ABT | -= 0x1000       - r3 - new SP value
+* g |     |                 - r4 - save/restore CPSR on entry/exit
+* r +-----+ <- SP_abt,
+* o |     |    SL_fiq        Declared as "weak" so that user can write and use
+* w | FIQ | -= 0x1000      his own implementation if current doesn't fit.
+* t |     |
+* h +-----+ <- initial SP,
+*           becomes SP_fiq
+*
+******************************************************************************/
+	.align	0
+	FUNC_START	_stack_init
+	.weak FUNCTION (_stack_init)
+	FN_EH_START
+
+	/* M profile doesn't have CPSR register.  */
+#if (__ARM_ARCH_PROFILE != 'M')
+	/* Following code is compatible for both ARM and Thumb ISA.  */
+	mrs	r4, CPSR
+	/* Test mode bits - in User of all are 0.  */
+	tst	r4, #(CPSR_M_MASK)
+	/* "eq" means r4 AND #0x0F is 0.  */
+	beq	.Lskip_cpu_modes
+
+	mov	r3, sp /* Save input SP value.  */
+
+	/* FIQ mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_FIQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	sl, sp, #0x1000	/* FIQ mode has its own SL.  */
+
+	/* Abort mode, interrupts disabled.  */
+	mov	r3, sl
+	mov	r1, #(CPSR_M_ABT|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x1000
+
+	/* Undefined mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_UND|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x1000
+
+	/* IRQ mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_IRQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x2000
+
+	/* Supervisory mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_SVR|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+
+	sub	r3, r3, #0x8000	/* Min size 32k.  */
+	bic	r3, r3, #0x00FF	/* Align with current 64k block.  */
+	bic	r3, r3, #0xFF00
+
+# if __ARM_ARCH >= 4
+	/* System (shares regs with User) mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_SYS|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+# else
+	/* Keep this for ARMv3, but GCC actually dropped it.  */
+	/* Move value into user mode sp without changing modes,  */
+	/* via '^' form of ldm.  */
+	str	r3, [r3, #-4]
+	ldmdb	r3, {sp}^
+# endif
+
+	/* Back to original mode, presumably SVC, with diabled FIQ/IRQ.  */
+	orr	r4, r4, #(CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r4
+
+.Lskip_cpu_modes:
+#endif
+
+	/* Set SL register.  */
+#if defined (ARM_RDI_MONITOR) /* semihosting */
+	cmp	r2, #0
+	beq	.Lsl_forced_zero
+	/* Allow slop for stack overflow handling and small frames.  */
+# ifdef THUMB1_ONLY
+	adds	r2, #128
+	adds	r2, #128
+	mov	sl, r2
+# else
+	add	sl, r2, #256
+# endif
+.Lsl_forced_zero:
+
+#else /* standalone */
+	/* r3 contains SP for System/User mode. Set SL = SP - 0x10000.  */
+	#ifdef THUMB1_ONLY
+	movs	r2, #64
+	lsls	r2, r2, #10
+	subs	r2, r3, r2
+	mov	sl, r2
+	#else
+	/* Still assumes 256bytes below SL.  */
+	sub	sl, r3, #64 << 10
+	#endif
+#endif
+
+	FN_RETURN
+	FN_EH_END
+
+
 /*******************************************************************************
 * Main library startup code.
 *******************************************************************************/
 	.align 	0
 	FUNC_START	_mainCRTStartup
 	FUNC_START	_start
-#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
-	/* Annotation for EABI unwinding tables.  */
-	.fnstart
-#endif
+	FN_EH_START
 
 	/* __ARM_ARCH_PROFILE is defined from GCC 4.8 onwards, however __ARM_ARCH_7A
 	has been defined since 4.2 onwards, which is when v7-a support was added
@@ -144,42 +313,33 @@
 .LC32:	
 	ldr	r1, [r0, #8]
 	ldr	r2, [r0, #12]
-	/*  We skip setting sp/sl if 0 returned from semihosting. 
+	/*  We skip setting SP/SL if 0 returned from semihosting.
 	    - According to semihosting docs, if 0 returned from semihosting,
 	      the system was unable to calculate the real value, so it's ok
-	      to skip setting sp/sl to 0 here.
+	      to skip setting SP/SL to 0 here.
 	    - Considering M-profile processors, We might want to initialize
 	      sp by the first entry of vector table and return 0 to SYS_HEAPINFO
-	      semihosting call, which will be skipped here.  */
+	      semihosting call, which will be skipped here.
+	    - Considering R-profile processors there is no automatic SP init by hardware
+	      so we need to initialize it by default value.  */
+	ldr	r3, .Lstack
 	cmp	r1, #0
 	beq	.LC26
-	mov	sp, r1
+	mov	r3, r1
 .LC26:
-	cmp	r2, #0
-	beq	.LC27
+	mov	sp, r3
 
-	/*  Allow slop for stack overflow handling and small frames.  */
-#ifdef THUMB1_ONLY
-	adds	r2, #128
-	adds	r2, #128
-	mov	sl, r2
-#else
-	add	sl, r2, #256
-#endif
+	/* r2 (SL value) will be used in _stack_init.  */
+	bl FUNCTION (_stack_init)
 
-.LC27:
-#else
-	/*  Set up the stack pointer to a fixed value.  */
+
+#else /* standalone */
+	/*  Set up the stack pointer to a fixed value. */
 	/*  Changes by toralf:
 	    - Allow linker script to provide stack via __stack symbol - see
 	      defintion of .Lstack
 	    - Provide "hooks" that may be used by the application to add
-	      custom init code - see .Lhwinit and .Lswinit	
-	    - Go through all execution modes and set up stack for each of them.
-	      Loosely based on init.s from ARM/Motorola example code.
-              Note: Mode switch via CPSR is not allowed once in non-privileged
-		    mode, so we take care not to enter "User" to set up its sp,
-		    and also skip most operations if already in that mode.  */
+	      custom init code - see .Lhwinit and .Lswinit.  */
 
 	ldr	r3, .Lstack
 	cmp	r3, #0
@@ -198,57 +358,10 @@
 		 have somehow missed it below (in which case it gets the same
 		 value as FIQ - not ideal, but better than nothing).  */
 	mov	sp, r3
-#ifdef PREFER_THUMB
-	/* XXX Fill in stack assignments for interrupt modes.  */
-#else
-	mrs	r2, CPSR
-	tst	r2, #0x0F	/* Test mode bits - in User of all are 0.  */
-	beq	.LC23		/* "eq" means r2 AND #0x0F is 0.  */
-	msr     CPSR_c, #0xD1	/* FIRQ mode, interrupts disabled.  */
-	mov 	sp, r3
-	sub	sl, sp, #0x1000	/* This mode also has its own sl (see below).  */
-	
-	mov	r3, sl	
-	msr     CPSR_c, #0xD7	/* Abort mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x1000
-
-	msr     CPSR_c, #0xDB	/* Undefined mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x1000
-
-	msr     CPSR_c, #0xD2	/* IRQ mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x2000
-		
-	msr     CPSR_c, #0xD3	/* Supervisory mode, interrupts disabled.  */
 
-	mov	sp, r3
-	sub	r3, r3, #0x8000	/* Min size 32k.  */
-	bic	r3, r3, #0x00FF	/* Align with current 64k block.  */
-	bic	r3, r3, #0xFF00
+	/* We don't care of r2 value in standalone.  */
+	bl FUNCTION (_stack_init)
 
-	str	r3, [r3, #-4]	/* Move value into user mode sp without */ 
-	ldmdb	r3, {sp}^       /* changing modes, via '^' form of ldm.  */ 
-	orr	r2, r2, #0xC0	/* Back to original mode, presumably SVC, */
-	msr	CPSR_c, r2	/* with FIQ/IRQ disable bits forced to 1.  */
-#endif	
-.LC23:
-	/* Setup a default stack-limit in-case the code has been
-	   compiled with "-mapcs-stack-check".  Hard-wiring this value
-	   is not ideal, since there is currently no support for
-	   checking that the heap and stack have not collided, or that
-	   this default 64k is enough for the program being executed.
-	   However, it ensures that this simple crt0 world will not
-	   immediately cause an overflow event:  */
-#ifdef THUMB1_ONLY
-	movs	r2, #64
-	lsls	r2, r2, #10
-	subs	r2, r3, r2
-	mov	sl, r2
-#else
-	sub	sl, r3, #64 << 10	/* Still assumes 256bytes below sl.  */
-#endif
 #endif
 #endif
 	/* Zero the memory in the .bss section.  */
@@ -447,6 +560,8 @@ change_back:
 	swi	SWI_Exit
 #endif
 	
+	FN_EH_END
+
 	/* For Thumb, constants must be after the code since only 
 	   positive offsets are supported for PC relative addresses.  */
 	.align 0
@@ -464,9 +579,6 @@ change_back:
 #else
 	.word	0x80000			/* Top of RAM on the PIE board.  */
 #endif
-
-.Lstack:	
-	.word	__stack
 .Lhwinit:	
 	.word	FUNCTION (hardware_init_hook)
 .Lswinit:
@@ -479,17 +591,16 @@ change_back:
 	   and only if, a normal version of the same symbol isn't provided
 	   e.g. by a linker script or another object file.)  */
 
-	.weak __stack
 	.weak FUNCTION (hardware_init_hook) 
 	.weak FUNCTION (software_init_hook)
 #endif
 	
 #endif
-#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
-	/* Protect against unhandled exceptions.  */
-	.cantunwind
-	.fnend
-#endif
+
+.Lstack:
+	.word	__stack
+	.weak	__stack
+
 .LC1:
 	.word	__bss_start__
 .LC2:
diff --git a/newlib/libc/sys/arm/arm.h b/newlib/libc/sys/arm/arm.h
index 0489f2d92..dbed81750 100644
--- a/newlib/libc/sys/arm/arm.h
+++ b/newlib/libc/sys/arm/arm.h
@@ -61,4 +61,30 @@
 # define HAVE_CALL_INDIRECT
 #endif
 
+/* A and R profiles (and legacy Arm).
+	Current Program Status Register (CPSR)
+	M[4:0]		Mode bits. M[4] is always 1 for 32-bit modes.
+	T[5]			1: Thumb, 0: ARM instruction set
+	F[6]			1: disables FIQ
+	I[7]			1: disables IRQ
+	A[8]			1: disables imprecise aborts
+	E[9]			0: Little-endian, 1: Big-endian
+	J[24]			1: Jazelle instruction set
+ */
+#define CPSR_M_USR			0x00	/* User mode.  */
+#define CPSR_M_FIQ			0x01	/* Fast Interrupt mode.  */
+#define CPSR_M_IRQ			0x02	/* Interrupt mode.  */
+#define CPSR_M_SVR			0x03	/* Supervisor mode.  */
+#define CPSR_M_MON			0x06	/* Monitor mode.  */
+#define CPSR_M_ABT			0x07	/* Abort mode.  */
+#define CPSR_M_HYP			0x0A	/* Hypervisor mode.  */
+#define CPSR_M_UND			0x0B	/* Undefined mode.  */
+#define CPSR_M_SYS			0x0F	/* System mode.  */
+#define CPSR_M_32BIT		0x10	/* 32-bit mode.  */
+#define CPSR_T_BIT			0x20	/* Thumb bit.  */
+#define CPSR_F_MASK			0x40	/* FIQ bit.  */
+#define CPSR_I_MASK			0x80	/* IRQ bit.  */
+
+#define CPSR_M_MASK			0x0F	/* Mode mask except M[4] */
+
 #endif /* _LIBGLOSS_ARM_H */
diff --git a/newlib/libc/sys/arm/crt0.S b/newlib/libc/sys/arm/crt0.S
index 3358d7014..24ccb0b04 100644
--- a/newlib/libc/sys/arm/crt0.S
+++ b/newlib/libc/sys/arm/crt0.S
@@ -59,6 +59,21 @@
 .endm
 #endif
 
+/* Annotation for EABI unwinding tables.  */
+.macro FN_EH_START
+#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+	.fnstart
+#endif
+.endm
+
+.macro FN_EH_END
+#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
+	/* Protect against unhandled exceptions.  */
+	.cantunwind
+	.fnend
+#endif
+.endm
+
 .macro indirect_call reg
 #ifdef HAVE_CALL_INDIRECT
 	blx \reg
@@ -68,16 +83,170 @@
 #endif
 .endm
 
+/* For armv4t and newer, toolchains will transparently convert
+   'bx lr' to 'mov pc, lr' if needed. GCC has deprecated support
+   for anything older than armv4t, but this should handle that
+   corner case in case anyone needs it anyway.  */
+.macro  FN_RETURN
+#if __ARM_ARCH <= 4 && __ARM_ARCH_ISA_THUMB == 0
+	mov	pc, lr
+#else
+	bx	lr
+#endif
+.endm
+
+
+
+/******************************************************************************
+* User mode only:           This routine makes default target specific Stack
+*   +-----+ <- SL_sys,    Pointer initialization for different processor modes:
+*   |     |    SL_usr     FIQ, Abort, IRQ, Undefined, Supervisor, System (User)
+*   | SYS |               and setups a default Stack Limit in-case the code has
+*   | USR | -=0x10000     been compiled with "-mapcs-stack-check" for FIQ and
+*   |     |               System (User) modes.
+*   |     |
+*   +-----+ <- initial SP,
+*           becomes SP_sys   Hard-wiring SL value is not ideal, since there is
+*           and SL_usr     currently no support for checking that the heap and
+*                          stack have not collided, or that this default 64k is
+* All modes:               is enough for the program being executed. However,
+*   +-----+ <- SL_sys,     it ensures that this simple crt0 world will not
+*   |     |    SL_usr      immediately cause an overflow event.
+*   | SYS |
+*   | USR | -=0x10000        We go through all execution modes and set up SP
+*   |     |                for each of them.
+*   +-----+ <- SP_sys,
+*   |     |    SP_usr      Note:
+*   | SVC | -= 0x8000        Mode switch via CPSR is not allowed once in
+*   |     |                  non-privileged mode, so we take care not to enter
+*   +-----+ <- SP_svc        "User" to set up its sp, and also skip most
+*   |     |                  operations if already in that mode.
+*   | IRQ | -= 0x2000
+*   |     |                Input parameters:
+* ^ +-----+ <- SP_und       - sp - Initialized SP
+* s |     |                 - r2 - May contain SL value from semihosting
+* t | UND | -= 0x1000              SYS_HEAPINFO call
+* a |     |                Scratch registers:
+* c +-----+ <- SP_und       - r1 - new value of CPSR
+* k |     |                 - r2 - intermediate value (in standalone mode)
+*   | ABT | -= 0x1000       - r3 - new SP value
+* g |     |                 - r4 - save/restore CPSR on entry/exit
+* r +-----+ <- SP_abt,
+* o |     |    SL_fiq        Declared as "weak" so that user can write and use
+* w | FIQ | -= 0x1000      his own implementation if current doesn't fit.
+* t |     |
+* h +-----+ <- initial SP,
+*           becomes SP_fiq
+*
+******************************************************************************/
+	.align	0
+	FUNC_START	_stack_init
+	.weak FUNCTION (_stack_init)
+	FN_EH_START
+
+	/* M profile doesn't have CPSR register.  */
+#if (__ARM_ARCH_PROFILE != 'M')
+	/* Following code is compatible for both ARM and Thumb ISA.  */
+	mrs	r4, CPSR
+	/* Test mode bits - in User of all are 0.  */
+	tst	r4, #(CPSR_M_MASK)
+	/* "eq" means r4 AND #0x0F is 0.  */
+	beq	.Lskip_cpu_modes
+
+	mov	r3, sp /* Save input SP value.  */
+
+	/* FIQ mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_FIQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	sl, sp, #0x1000	/* FIQ mode has its own SL.  */
+
+	/* Abort mode, interrupts disabled.  */
+	mov	r3, sl
+	mov	r1, #(CPSR_M_ABT|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x1000
+
+	/* Undefined mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_UND|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x1000
+
+	/* IRQ mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_IRQ|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+	sub	r3, r3, #0x2000
+
+	/* Supervisory mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_SVR|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+
+	sub	r3, r3, #0x8000	/* Min size 32k.  */
+	bic	r3, r3, #0x00FF	/* Align with current 64k block.  */
+	bic	r3, r3, #0xFF00
+
+# if __ARM_ARCH >= 4
+	/* System (shares regs with User) mode, interrupts disabled.  */
+	mov	r1, #(CPSR_M_SYS|CPSR_M_32BIT|CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r1
+	mov	sp, r3
+# else
+	/* Keep this for ARMv3, but GCC actually dropped it.  */
+	/* Move value into user mode sp without changing modes,  */
+	/* via '^' form of ldm.  */
+	str	r3, [r3, #-4]
+	ldmdb	r3, {sp}^
+# endif
+
+	/* Back to original mode, presumably SVC, with diabled FIQ/IRQ.  */
+	orr	r4, r4, #(CPSR_I_MASK|CPSR_F_MASK)
+	msr	CPSR_c, r4
+
+.Lskip_cpu_modes:
+#endif
+
+	/* Set SL register.  */
+#if defined (ARM_RDI_MONITOR) /* semihosting */
+	cmp	r2, #0
+	beq	.Lsl_forced_zero
+	/* Allow slop for stack overflow handling and small frames.  */
+# ifdef THUMB1_ONLY
+	adds	r2, #128
+	adds	r2, #128
+	mov	sl, r2
+# else
+	add	sl, r2, #256
+# endif
+.Lsl_forced_zero:
+
+#else /* standalone */
+	/* r3 contains SP for System/User mode. Set SL = SP - 0x10000.  */
+	#ifdef THUMB1_ONLY
+	movs	r2, #64
+	lsls	r2, r2, #10
+	subs	r2, r3, r2
+	mov	sl, r2
+	#else
+	/* Still assumes 256bytes below SL.  */
+	sub	sl, r3, #64 << 10
+	#endif
+#endif
+
+	FN_RETURN
+	FN_EH_END
+
+
 /*******************************************************************************
 * Main library startup code.
 *******************************************************************************/
 	.align 	0
 	FUNC_START	_mainCRTStartup
 	FUNC_START	_start
-#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
-	/* Annotation for EABI unwinding tables.  */
-	.fnstart
-#endif
+	FN_EH_START
 
 /* Start by setting up a stack.  */
 #ifdef ARM_RDP_MONITOR
@@ -124,42 +293,33 @@
 .LC32:	
 	ldr	r1, [r0, #8]
 	ldr	r2, [r0, #12]
-	/*  We skip setting sp/sl if 0 returned from semihosting. 
+	/*  We skip setting SP/SL if 0 returned from semihosting.
 	    - According to semihosting docs, if 0 returned from semihosting,
 	      the system was unable to calculate the real value, so it's ok
-	      to skip setting sp/sl to 0 here.
+	      to skip setting SP/SL to 0 here.
 	    - Considering M-profile processors, We might want to initialize
 	      sp by the first entry of vector table and return 0 to SYS_HEAPINFO
-	      semihosting call, which will be skipped here.  */
+	      semihosting call, which will be skipped here.
+	    - Considering R-profile processors there is no automatic SP init by hardware
+	      so we need to initialize it by default value.  */
+	ldr	r3, .Lstack
 	cmp	r1, #0
 	beq	.LC26
-	mov	sp, r1
+	mov	r3, r1
 .LC26:
-	cmp	r2, #0
-	beq	.LC27
+	mov	sp, r3
 
-	/*  Allow slop for stack overflow handling and small frames.  */
-#ifdef THUMB1_ONLY
-	adds	r2, #128
-	adds	r2, #128
-	mov	sl, r2
-#else
-	add	sl, r2, #256
-#endif
+	/* r2 (SL value) will be used in _stack_init.  */
+	bl FUNCTION (_stack_init)
 
-.LC27:
-#else
-	/*  Set up the stack pointer to a fixed value.  */
+
+#else /* standalone */
+	/*  Set up the stack pointer to a fixed value. */
 	/*  Changes by toralf:
 	    - Allow linker script to provide stack via __stack symbol - see
 	      defintion of .Lstack
 	    - Provide "hooks" that may be used by the application to add
-	      custom init code - see .Lhwinit and .Lswinit	
-	    - Go through all execution modes and set up stack for each of them.
-	      Loosely based on init.s from ARM/Motorola example code.
-              Note: Mode switch via CPSR is not allowed once in non-privileged
-		    mode, so we take care not to enter "User" to set up its sp,
-		    and also skip most operations if already in that mode.  */
+	      custom init code - see .Lhwinit and .Lswinit.  */
 
 	ldr	r3, .Lstack
 	cmp	r3, #0
@@ -178,57 +338,10 @@
 		 have somehow missed it below (in which case it gets the same
 		 value as FIQ - not ideal, but better than nothing).  */
 	mov	sp, r3
-#ifdef PREFER_THUMB
-	/* XXX Fill in stack assignments for interrupt modes.  */
-#else
-	mrs	r2, CPSR
-	tst	r2, #0x0F	/* Test mode bits - in User of all are 0.  */
-	beq	.LC23		/* "eq" means r2 AND #0x0F is 0.  */
-	msr     CPSR_c, #0xD1	/* FIRQ mode, interrupts disabled.  */
-	mov 	sp, r3
-	sub	sl, sp, #0x1000	/* This mode also has its own sl (see below).  */
-	
-	mov	r3, sl	
-	msr     CPSR_c, #0xD7	/* Abort mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x1000
-
-	msr     CPSR_c, #0xDB	/* Undefined mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x1000
-
-	msr     CPSR_c, #0xD2	/* IRQ mode, interrupts disabled.  */
-	mov	sp, r3
-	sub	r3, r3, #0x2000
-		
-	msr     CPSR_c, #0xD3	/* Supervisory mode, interrupts disabled.  */
 
-	mov	sp, r3
-	sub	r3, r3, #0x8000	/* Min size 32k.  */
-	bic	r3, r3, #0x00FF	/* Align with current 64k block.  */
-	bic	r3, r3, #0xFF00
+	/* We don't care of r2 value in standalone.  */
+	bl FUNCTION (_stack_init)
 
-	str	r3, [r3, #-4]	/* Move value into user mode sp without */ 
-	ldmdb	r3, {sp}^       /* changing modes, via '^' form of ldm.  */ 
-	orr	r2, r2, #0xC0	/* Back to original mode, presumably SVC, */
-	msr	CPSR_c, r2	/* with FIQ/IRQ disable bits forced to 1.  */
-#endif	
-.LC23:
-	/* Setup a default stack-limit in-case the code has been
-	   compiled with "-mapcs-stack-check".  Hard-wiring this value
-	   is not ideal, since there is currently no support for
-	   checking that the heap and stack have not collided, or that
-	   this default 64k is enough for the program being executed.
-	   However, it ensures that this simple crt0 world will not
-	   immediately cause an overflow event:  */
-#ifdef THUMB1_ONLY
-	movs	r2, #64
-	lsls	r2, r2, #10
-	subs	r2, r3, r2
-	mov	sl, r2
-#else
-	sub	sl, r3, #64 << 10	/* Still assumes 256bytes below sl.  */
-#endif
 #endif
 #endif
 	/* Zero the memory in the .bss section.  */
@@ -421,6 +534,8 @@ change_back:
 	swi	SWI_Exit
 #endif
 	
+	FN_EH_END
+
 	/* For Thumb, constants must be after the code since only 
 	   positive offsets are supported for PC relative addresses.  */
 	.align 0
@@ -438,9 +553,6 @@ change_back:
 #else
 	.word	0x80000			/* Top of RAM on the PIE board.  */
 #endif
-
-.Lstack:	
-	.word	__stack
 .Lhwinit:	
 	.word	FUNCTION (hardware_init_hook)
 .Lswinit:
@@ -453,17 +565,16 @@ change_back:
 	   and only if, a normal version of the same symbol isn't provided
 	   e.g. by a linker script or another object file.)  */
 
-	.weak __stack
 	.weak FUNCTION (hardware_init_hook) 
 	.weak FUNCTION (software_init_hook)
 #endif
 	
 #endif
-#if defined(__ELF__) && !defined(__USING_SJLJ_EXCEPTIONS__)
-	/* Protect against unhandled exceptions.  */
-	.cantunwind
-	.fnend
-#endif
+
+.Lstack:
+	.word	__stack
+	.weak	__stack
+
 .LC1:
 	.word	__bss_start__
 .LC2:
-- 
2.17.1

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment.
  2019-07-19 13:22 [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment alfedotov
  2019-07-19 13:22 ` [PATCH v2 2/2] [Arm] Stack Pointer and Stack Limit initialization refactored alfedotov
@ 2019-07-22  8:52 ` Corinna Vinschen
  1 sibling, 0 replies; 3+ messages in thread
From: Corinna Vinschen @ 2019-07-22  8:52 UTC (permalink / raw)
  To: newlib

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On Jul 19 08:22, alfedotov@gmail.com wrote:
> From: Alexander Fedotov <alfedotov@gmail.com>

This patch has already gone in, commit a0b0a4a01820.


Corinna

-- 
Corinna Vinschen
Cygwin Maintainer
Red Hat

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^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2019-07-22  8:52 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-19 13:22 [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment alfedotov
2019-07-19 13:22 ` [PATCH v2 2/2] [Arm] Stack Pointer and Stack Limit initialization refactored alfedotov
2019-07-22  8:52 ` [PATCH v2 1/2] Align comments and spaces in libgloss/arm/crt0.S and newlib/libc/sys/arm/crt0.S to ease further code alignment Corinna Vinschen

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