* arm/crt0.S: Support armv6-m processors in libgloss.

	* arm/swi.h: Likewise.
	* arm/trap.S: Likewise.
	* arm/redboot-crt0.S: Likewise.
	* arm/linux-crt0.c: Likewise.
	* arm/arm.h: New.

7 files changed, 163 insertions, 45 deletions

diff --git a/libgloss/ChangeLog b/libgloss/ChangeLog
index f37af8b2e..e433ec57c 100644
--- a/libgloss/ChangeLog
+++ b/libgloss/ChangeLog
@@ -1,3 +1,12 @@
+2011-07-13  Bin Cheng <bin.cheng@arm.com>
+
+	* arm/crt0.S: Support armv6-m processors in libgloss.
+	* arm/swi.h: Likewise.
+	* arm/trap.S: Likewise.
+	* arm/redboot-crt0.S: Likewise.
+	* arm/linux-crt0.c: Likewise.
+	* arm/arm.h: New.
+
 2011-07-01  Mike Frysinger  <vapier@gentoo.org>
 
 	* bfin/syscalls.c (_getpid): Call do_syscall with func argument n and
diff --git a/libgloss/arm/arm.h b/libgloss/arm/arm.h
new file mode 100644
index 000000000..e8c9d25a3
--- /dev/null
+++ b/libgloss/arm/arm.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2011 ARM Ltd
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the company may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY ARM LTD ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL ARM LTD BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _LIBGLOSS_ARM_H
+#define _LIBGLOSS_ARM_H
+
+/* __thumb2__ stands for thumb on armva7(A/R/M/EM) architectures,
+   __ARM_ARCH_6M__ stands for armv6-M(thumb only) architecture,
+   __ARM_ARCH_7M__ stands for armv7-M(thumb only) architecture.
+   __ARM_ARCH_7EM__ stands for armv7e-M(thumb only) architecture.
+   There are some macro combinations used many times in libgloss/arm,
+   like (__thumb2__ || (__thumb__ && __ARM_ARCH_6M__)), so factor
+   it out and use THUMB_V7_V6M instead, which stands for thumb on
+   v6-m/v7 arch as the combination does.  */
+#if defined(__thumb2__) || (defined(__thumb__) && defined(__ARM_ARCH_6M__))
+# define THUMB_V7_V6M
+#endif
+
+/* The (__ARM_ARCH_7EM__ || __ARM_ARCH_7M__ || __ARM_ARCH_6M__) combination
+   stands for cortex-M profile architectures, which don't support ARM state.
+   Factor it out and use THUMB_V7M_V6M instead.  */
+#if defined(__ARM_ARCH_7M__)     \
+    || defined(__ARM_ARCH_7EM__) \
+    || defined(__ARM_ARCH_6M__)
+# define THUMB_V7M_V6M
+#endif
+
+#endif /* _LIBGLOSS_ARM_H */
diff --git a/libgloss/arm/crt0.S b/libgloss/arm/crt0.S
index ea5163ae1..c98cd2cab 100644
--- a/libgloss/arm/crt0.S
+++ b/libgloss/arm/crt0.S
@@ -1,4 +1,5 @@
 #include "newlib.h"
+#include "arm.h"
 #include "swi.h"
 
 /* ANSI concatenation macros.  */
@@ -18,8 +19,8 @@
 
 /* .text is used instead of .section .text so it works with arm-aout too.  */
 	.text
-#if defined(__thumb2__)
 	.syntax unified
+#ifdef THUMB_V7_V6M
 	.thumb
 .macro FUNC_START name
 	.global \name
@@ -48,25 +49,57 @@
 	/*  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 */
-	ldr	sl, .LC2	/*  stack limit is at end of data */
-	add	sl, sl, #256	/*  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 __ARM_ARCH_6M__
+	ldr	r0, .LC2
+	adds	r0, #128
+	adds	r0, #128
+	mov	sl, r0
+#else
+	ldr	sl, .LC2
+	add	sl, sl, #256
+#endif
 #else
 #ifdef ARM_RDI_MONITOR
 	/*  Issue Angel SWI to read stack info */
-	mov	r0, #AngelSWI_Reason_HeapInfo
+	movs	r0, #AngelSWI_Reason_HeapInfo
 	adr	r1, .LC0	/*  point at ptr to 4 words to receive data */
-#if defined(__thumb2__)
+#ifdef THUMB_V7M_V6M
 	bkpt	AngelSWI
+#elif defined(__thumb2__)
+	/*  We are in thumb mode for startup on armv7 architectures. */
+	AngelSWIAsm	AngelSWI
 #else
-	/*  We are always in ARM mode for startup */
+	/*  We are always in ARM mode for startup on pre armv7 archs. */
 	AngelSWIAsm	AngelSWI_ARM
 #endif
 	ldr	r0, .LC0	/*  point at values read */
-	ldr	sp, [r0, #8]
-	ldr	sl, [r0, #12]
-	add	sl, sl, #256	/*  allow slop for stack overflow handling */
-				/*  and small frames */
+	ldr	r1, [r0, #8]
+	ldr	r2, [r0, #12]
+	/*  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.
+	    - 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. */
+	cmp	r1, #0
+	beq	.LC26
+	mov	sp, r1
+.LC26:
+	cmp	r2, #0
+	beq	.LC27
+	/*  allow slop for stack overflow handling and small frames */
+#ifdef __ARM_ARCH_6M__
+	adds	r2, #128
+	adds	r2, #128
+	mov	sl, r2
+#else
+	add	sl, r2, #256
+#endif
+.LC27:
 #else
 	/*  Set up the stack pointer to a fixed value */
 	/*  Changes by toralf:
@@ -85,13 +118,19 @@
 #ifdef __thumb2__
 	it	eq
 #endif	
+#ifdef __ARM_ARCH_6M__
+	bne	.LC28
+	ldr	r3, .LC0
+.LC28:
+#else
 	ldreq	r3, .LC0
+#endif
 	/* 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.) */
 	mov	sp, r3
-#ifdef __thumb2__
+#ifdef THUMB_V7_V6M
 	/* XXX Fill in stack assignments for interrupt modes.  */
 #else
 	mrs	r2, CPSR
@@ -134,20 +173,27 @@
 	   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 __ARM_ARCH_6M__
+	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.  */
-	mov 	a2, #0			/* Second arg: fill value */
+	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	a3, .LC2	
-	sub	a3, a3, a1		/* Third arg: length of block */
+	subs	a3, a3, a1		/* Third arg: length of block */
 	
 
-#if defined(__thumb__) && !defined(__thumb2__)
+#if defined(__thumb__) && !defined(THUMB_V7_V6M)
 	/* Enter Thumb mode.... */
 	add	a4, pc, #1	/* Get the address of the Thumb block */
 	bx	a4		/* Go there and start Thumb decoding  */
@@ -185,8 +231,8 @@ __change_mode:
 #endif
 
 .LC25:	
-	mov	r0, #0		/*  no arguments  */
-	mov	r1, #0		/*  no argv either */
+	movs	r0, #0		/*  no arguments  */
+	movs	r1, #0		/*  no argv either */
 #else
 	/* Need to set up standard file handles */
 	bl	FUNCTION (initialise_monitor_handles)
@@ -195,13 +241,13 @@ __change_mode:
 	swi	SWI_GetEnv	/*  sets r0 to point to the command line */
 	mov	r1, r0
 #else
-	mov	r0, #AngelSWI_Reason_GetCmdLine
+	movs	r0, #AngelSWI_Reason_GetCmdLine
 	adr	r1, .LC30	/*  Space for command line */
 	AngelSWIAsm	AngelSWI
 	ldr	r1, .LC30
 #endif
 	/*  Parse string at r1 */
-	mov	r0, #0		/*  count of arguments so far */
+	movs	r0, #0		/*  count of arguments so far */
 	/* Push a NULL argument onto the end of the list.  */
 #ifdef __thumb__
 	push	{r0}
@@ -212,7 +258,7 @@ __change_mode:
 /*  Skip leading blanks */
 #ifdef __thumb__
 	ldrb	r3, [r1]
-	add	r1, #1
+	adds	r1, #1
 #else
 	ldrb	r3, [r1], #1
 #endif
@@ -232,8 +278,8 @@ __change_mode:
 	b	.LC22
 
 .LC21:
-	mov	r2, #' '	/*  terminator type */
-	sub	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, #'\''
@@ -248,11 +294,11 @@ __change_mode:
 #else
 	stmfd	sp!, {r1}
 #endif
-	add	r0, r0, #1
+	adds	r0, r0, #1
 .LC11:
 #ifdef __thumb__
 	ldrb	r3, [r1]
-	add	r1, #1
+	adds	r1, #1
 #else
 	ldrb	r3, [r1], #1
 #endif
@@ -260,8 +306,8 @@ __change_mode:
 	beq	.LC12
 	cmp	r2, r3		/*  reached terminator? */
 	bne	.LC11
-	mov	r2, #0
-	sub	r3, r1, #1
+	movs	r2, #0
+	subs	r3, r1, #1
 	strb	r2, [r3]	/*  terminate the arg string */
 	b	.LC10
 
@@ -270,23 +316,23 @@ __change_mode:
 	/* We've now got the stacked args in order reverse the */
 #ifdef __thumb__
 	mov	r2, r0
-	lsl	r2, #2
+	lsls	r2, #2
 	add	r2, sp
 	mov	r3, sp
 .LC15:	cmp	r2, r3
 	bls	.LC14
-	sub	r2, #4
+	subs	r2, #4
 	ldr	r4, [r2]
 	ldr	r5, [r3]
 	str	r5, [r2]
 	str	r4, [r3]
-	add	r3, #4
+	adds	r3, #4
 	b	.LC15
 .LC14:	
 	/* Ensure doubleword stack alignment.  */
 	mov	r4, sp
-	mov	r5, #7
-	bic	r4, r5
+	movs	r5, #7
+	bics	r4, r5
 	mov	sp, r4
 #else
 	add	r2, sp, r0, LSL #2	/* End of args */
@@ -319,7 +365,7 @@ __change_mode:
 
 	bl	FUNCTION (exit)		/* Should not return.  */
 
-#if defined(__thumb__) && !defined(__thumb2__)
+#if defined(__thumb__) && !defined(THUMB_V7_V6M)
 	/* Come out of Thumb mode.  This code should be redundant.  */
 
 	mov	a4, pc
diff --git a/libgloss/arm/linux-crt0.c b/libgloss/arm/linux-crt0.c
index 1fe2499e4..2c1dd4af3 100644
--- a/libgloss/arm/linux-crt0.c
+++ b/libgloss/arm/linux-crt0.c
@@ -8,10 +8,11 @@
 
 #include <stdlib.h>
 #include <unistd.h>
+#include "arm.h"
 
 static int _main(int argc, char *argv[]) __attribute__((noreturn));
 
-#if __thumb__ && !__thumb2__
+#if defined(__thumb__) && !defined(THUMB_V7_V6M)
 asm("\n"
 	".code 32\n"
 	".global _start\n"
diff --git a/libgloss/arm/redboot-crt0.S b/libgloss/arm/redboot-crt0.S
index 2499ac091..dcd042c23 100644
--- a/libgloss/arm/redboot-crt0.S
+++ b/libgloss/arm/redboot-crt0.S
@@ -1,3 +1,4 @@
+#include "arm.h"
 	
     .file   "crt0.S"
 	
@@ -11,14 +12,14 @@
 #endif
 
     .text
+	.syntax unified
      /* Setup the assembly entry point.  */
-#ifdef __thumb2__
+#ifdef THUMB_V7_V6M
 .macro FUNC_START name
 	.global \name
 	.thumb_func
 \name:
 .endm
-	.syntax unified
 	.thumb
 #else
 .macro FUNC_START name
@@ -29,11 +30,15 @@
 #endif
 	FUNC_START SYM_NAME(start)
 	FUNC_START SYM_NAME(_start)
+    /* Unnecessary to set fp for v6-m/v7-m, which don't support
+       ARM state.  */
+#ifndef THUMB_V7M_V6M
 	mov	fp, #0	/* Null frame pointer.  */
-	mov	r7, #0	/* Null frame pointer for Thumb.  */
+#endif
+	movs	r7, #0	/* Null frame pointer for Thumb.  */
 
 	/* Enable interrupts for gdb debugging.  */
-#ifdef __thumb2__
+#ifdef THUMB_V7_V6M
 	cpsie if
 #else
 	mrs    r0, cpsr
@@ -41,10 +46,10 @@
 	msr    cpsr, r0
 #endif
 	
-	mov 	a2, #0			/* Second arg: fill value.  */
+	movs 	a2, #0			/* Second arg: fill value.  */
 	ldr	a1, .LC1		/* First arg: start of memory block.  */
 	ldr	a3, .LC2	
-	sub	a3, a3, a1		/* Third arg: length of block.  */
+	subs	a3, a3, a1		/* Third arg: length of block.  */
 
 #ifdef	GCRT0
 	/* Zero out the bss without using memset. 
@@ -62,7 +67,8 @@
 	/* Nothing to left to clear.  */
 #endif
 
-#if defined(__thumb__) && !defined(__thumb2__)	/* Enter Thumb mode. */
+#if defined(__thumb__) && !defined(THUMB_V7_V6M)
+	/* Enter Thumb mode. */
 	add	a4, pc, #1	/* Get the address of the Thumb block.  */
 	bx	a4		/* Go there and start Thumb decoding.   */
 
@@ -76,7 +82,7 @@ __change_mode:
 	bl	SYM_NAME(memset)
 #endif
 	bl	SYM_NAME(__get_memtop)
-	sub	r0, r0, #32
+	subs	r0, r0, #32
 	mov	sp, r0
 
 #ifdef __USES_INITFINI__
@@ -89,7 +95,7 @@ __change_mode:
 	bl	SYM_NAME (_init)
 #endif	
 
-	mov 	a1, #0
+	movs 	a1, #0
 	ldr	a2, .LC3
 	mov	a3, a2
 	bl	SYM_NAME(main)
diff --git a/libgloss/arm/swi.h b/libgloss/arm/swi.h
index 7638dbe4e..0f9313447 100644
--- a/libgloss/arm/swi.h
+++ b/libgloss/arm/swi.h
@@ -1,3 +1,5 @@
+#include "arm.h"
+
 /* SWI numbers for RDP (Demon) monitor.  */
 #define SWI_WriteC                 0x0
 #define SWI_Write0                 0x2
@@ -33,8 +35,8 @@
 #else
 #define AngelSWI 			AngelSWI_ARM
 #endif
-/* For Thumb-2 code use the BKPT instruction instead of SWI.  */
-#ifdef __thumb2__
+/* For thumb only architectures use the BKPT instruction instead of SWI.  */
+#ifdef THUMB_V7M_V6M
 #define AngelSWIInsn			"bkpt"
 #define AngelSWIAsm			bkpt
 #else
diff --git a/libgloss/arm/trap.S b/libgloss/arm/trap.S
index 21b6937f9..9eb39069a 100644
--- a/libgloss/arm/trap.S
+++ b/libgloss/arm/trap.S
@@ -1,5 +1,6 @@
+#include "arm.h"
         /* Run-time exception support */
-#if !defined(__thumb2__)
+#ifndef THUMB_V7_V6M
 #include "swi.h"
 
 /* .text is used instead of .section .text so it works with arm-aout too.  */