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GNU C Library master sources branch roland/arm-avoid-pc created. glibc-2.17-318-gd3f60a7

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The branch, roland/arm-avoid-pc has been created
        at  d3f60a72df5f2cc46b8f71bcf9b3fed2e5486ec2 (commit)

- Log -----------------------------------------------------------------
http://sources.redhat.com/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=d3f60a72df5f2cc46b8f71bcf9b3fed2e5486ec2

commit d3f60a72df5f2cc46b8f71bcf9b3fed2e5486ec2
Author: Roland McGrath <roland@hack.frob.com>
Date:   Fri Mar 1 16:34:15 2013 -0800

    ARM: Support avoiding pc as destination register.

diff --git a/ports/ChangeLog.arm b/ports/ChangeLog.arm
index 28ec8f9..699f751 100644
--- a/ports/ChangeLog.arm
+++ b/ports/ChangeLog.arm
@@ -1,3 +1,9 @@
+2013-03-01  Roland McGrath  <roland@hack.frob.com>
+
+	* sysdeps/arm/arm-features.h: Add comment about ARM_NO_PC_DEST.
+	* sysdeps/arm/memcpy.S [ARM_NO_PC_DEST]: Avoid pc as destination.
+	* sysdeps/arm/memmove.S [ARM_NO_PC_DEST]: Likewise.
+
 2013-02-28  Richard Henderson <rth@redhat.com>
 
 	* sysdeps/arm/preconfigure: Adjust scan for __ARM_ARCH_* defines.
diff --git a/ports/sysdeps/arm/arm-features.h b/ports/sysdeps/arm/arm-features.h
index 31801cf..63fd692 100644
--- a/ports/sysdeps/arm/arm-features.h
+++ b/ports/sysdeps/arm/arm-features.h
@@ -36,4 +36,9 @@
    at runtime (or that we never care about its state) and so need not
    be checked for.  */
 
+/* An OS-specific arm-features.h file may define ARM_NO_PC_DEST to
+   indicate that instructions using pc as a destination register
+   must never be used.  */
+#define ARM_NO_PC_DEST 1 /* XXX testing */
+
 #endif  /* arm-features.h */
diff --git a/ports/sysdeps/arm/memcpy.S b/ports/sysdeps/arm/memcpy.S
index 98b9b47..a8691aa 100644
--- a/ports/sysdeps/arm/memcpy.S
+++ b/ports/sysdeps/arm/memcpy.S
@@ -88,7 +88,12 @@ ENTRY(memcpy)
 	CALGN(	bcs	2f			)
 	CALGN(	adr	r4, 6f			)
 	CALGN(	subs	r2, r2, r3		)  @ C gets set
+#ifndef ARM_NO_PC_DEST
 	CALGN(	add	pc, r4, ip		)
+#else
+	CALGN(	add	r4, r4, ip		)
+	CALGN(	bx	r4			)
+#endif
 
 	PLD(	pld	[r1, #0]		)
 2:	PLD(	subs	r2, r2, #96		)
@@ -107,8 +112,16 @@ ENTRY(memcpy)
 
 5:		ands	ip, r2, #28
 		rsb	ip, ip, #32
+#ifndef ARM_NO_PC_DEST
 		addne	pc, pc, ip		@ C is always clear here
 		b	7f
+#else
+		beq	7f
+		push	r10
+		cfi_adjust_cfa_offset (4)
+		add	r10, pc, ip
+		bx	r10
+#endif
 6:		nop
 		ldr	r3, [r1], #4
 		ldr	r4, [r1], #4
@@ -118,8 +131,13 @@ ENTRY(memcpy)
 		ldr	r8, [r1], #4
 		ldr	lr, [r1], #4
 
+#ifndef ARM_NO_PC_DEST
 		add	pc, pc, ip
 		nop
+#else
+		add	r10, pc, ip
+		bx	r10
+#endif
 		nop
 		str	r3, [r0], #4
 		str	r4, [r0], #4
@@ -129,6 +147,11 @@ ENTRY(memcpy)
 		str	r8, [r0], #4
 		str	lr, [r0], #4
 
+#ifndef ARM_NO_PC_DEST
+		pop	r10
+		cfi_adjust_cfa_offset (-4)
+#endif
+
 	CALGN(	bcs	2b			)
 
 7:		ldmfd	sp!, {r5 - r8}
@@ -146,7 +169,8 @@ ENTRY(memcpy)
 		strcsb	r4, [r0], #1
 		strcsb	ip, [r0]
 
-#if defined (__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)
+#if ((defined (__ARM_ARCH_4T__) && defined(__THUMB_INTERWORK__)) \
+     || defined (ARM_NO_PC_DEST))
 		ldmfd	sp!, {r0, r4, lr}
 		cfi_adjust_cfa_offset (-12)
 		cfi_restore (r4)
diff --git a/ports/sysdeps/arm/memmove.S b/ports/sysdeps/arm/memmove.S
index 059ca7a..f3f3935 100644
--- a/ports/sysdeps/arm/memmove.S
+++ b/ports/sysdeps/arm/memmove.S
@@ -104,7 +104,12 @@ ENTRY(memmove)
 	CALGN(	bcs	2f			)
 	CALGN(	adr	r4, 6f			)
 	CALGN(	subs	r2, r2, ip		)  @ C is set here
+#ifndef ARM_NO_PC_DEST
 	CALGN(	add	pc, r4, ip		)
+#else
+	CALGN(	add	r4, r4, ip		)
+	CALGN(	bx	r4			)
+#endif
 
 	PLD(	pld	[r1, #-4]		)
 2:	PLD(	subs	r2, r2, #96		)
@@ -123,8 +128,16 @@ ENTRY(memmove)
 
 5:		ands	ip, r2, #28
 		rsb	ip, ip, #32
+#ifndef ARM_NO_PC_DEST
 		addne	pc, pc, ip		@ C is always clear here
 		b	7f
+#else
+		beq	7f
+		push	r10
+		cfi_adjust_cfa_offset (4)
+		add	r10, pc, ip
+		bx	r10
+#endif
 6:		nop
 		ldr	r3, [r1, #-4]!
 		ldr	r4, [r1, #-4]!
@@ -134,8 +147,13 @@ ENTRY(memmove)
 		ldr	r8, [r1, #-4]!
 		ldr	lr, [r1, #-4]!
 
+#ifndef ARM_NO_PC_DEST
 		add	pc, pc, ip
 		nop
+#else
+		add	r10, pc, ip
+		bx	r10
+#endif
 		nop
 		str	r3, [r0, #-4]!
 		str	r4, [r0, #-4]!
@@ -145,6 +163,11 @@ ENTRY(memmove)
 		str	r8, [r0, #-4]!
 		str	lr, [r0, #-4]!
 
+#ifndef ARM_NO_PC_DEST
+		pop	r10
+		cfi_adjust_cfa_offset (-4)
+#endif
+
 	CALGN(	bcs	2b			)
 
 7:		ldmfd	sp!, {r5 - r8}
@@ -162,7 +185,8 @@ ENTRY(memmove)
 		strcsb	r4, [r0, #-1]!
 		strcsb	ip, [r0, #-1]
 
-#if defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)
+#if ((defined (__ARM_ARCH_4T__) && defined (__THUMB_INTERWORK__)) \
+     || defined (ARM_NO_PC_DEST))
 		ldmfd	sp!, {r0, r4, lr}
 		cfi_adjust_cfa_offset (-12)
 		cfi_restore (r4)

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