* arm/crt0.s: Support 0 heap base response from HeapInfo syscall.

libgloss/ChangeLog

@@ -1,3 +1,7 @@
+2011-09-29  Matthew Gretton-Dann  <matthew.gretton-dann@arm.com>
+
+	* arm/crt0.s: Support 0 heap base response from HeapInfo syscall.
+
 2011-09-29  Bin Cheng  <bin.cheng@arm.com>
 
 	* arm/arm.h (HAVE_CALL_INDIRECT): Define.

libgloss/arm/crt0.S

@@ -86,6 +86,17 @@
 	AngelSWIAsm	AngelSWI_ARM
 #endif
 	ldr	r0, .LC0	/*  point at values read */
+
+	ldr     r1, [r0, #0]
+	cmp     r1, #0
+	bne     .LC32
+	/* If the heap base value [r0, #0] is 0 then the heap base is actually 
+	   at the end of program data (i.e. __end__). See:
+           http://infocenter.arm.com/help/topic/com.arm.doc.dui0471-/Bacbefaa.html
+	   for more information.  */
+	ldr     r1, .LC31
+	str     r1, [r0, #0]
+.LC32:	
 	ldr	r1, [r0, #8]
 	ldr	r2, [r0, #12]
 	/*  We skip setting sp/sl if 0 returned from semihosting. 
@@ -437,6 +448,8 @@ change_back:
 .LC30:
 	.word	CommandLine
 	.word	255
+.LC31:
+	.word	__end__
 
 /*  Workspace for Angel calls.  */
 	.data