Fixed stack checking for embedded target. Based on work by Christo Crause

git-svn-id: trunk@42157 -
(cherry picked from commit 2f501be2a0a17091460c8307862671cb9dbff45b)

rtl/avr/avr.inc

@@ -113,6 +113,8 @@ function get_caller_frame(framebp:pointer;addr:pointer=nil):pointer;assembler;no
 {$define FPC_SYSTEM_HAS_SPTR}
 Function Sptr : pointer;assembler;nostackframe;
   asm
+    in r24, 0x3d
+    in r25, 0x3e
   end;
 
 

rtl/embedded/system.pp

@@ -20,6 +20,8 @@ Unit System;
                                     interface
 {*****************************************************************************}
 
+{$define FPC_SYSTEM_HAS_STACKTOP}
+
 {$define FPC_IS_SYSTEM}
 {$define HAS_CMDLINE}
 
@@ -202,6 +204,14 @@ const calculated_cmdline:Pchar=nil;
 {*****************************************************************************
                        Misc. System Dependent Functions
 *****************************************************************************}
+var
+ _stack_top: record end; external name '_stack_top';
+
+function StackTop: pointer;
+begin
+  StackTop:=@_stack_top;
+end;
+
 
 procedure haltproc;cdecl;external name '_haltproc';
 
@@ -276,7 +286,7 @@ begin
 end;
 
 var
-  initialstkptr : Pointer; // external name '__stkptr';
+  initialstkptr : record end; external name '_stack_top';
 {$endif FPC_HAS_FEATURE_STACKCHECK}
 
 begin
@@ -293,7 +303,7 @@ begin
 
 {$ifdef FPC_HAS_FEATURE_STACKCHECK}
   StackLength := CheckInitialStkLen(initialStkLen);
-  StackBottom := initialstkptr - StackLength;
+  StackBottom := @initialstkptr - StackLength;
 {$endif FPC_HAS_FEATURE_STACKCHECK}
 
 {$ifdef FPC_HAS_FEATURE_EXCEPTIONS}

rtl/inc/system.inc

@@ -44,7 +44,11 @@ type
 {$endif FPC_HAS_FEATURE_TEXTIO}
 
 const
+{$ifdef CPUAVR}
+  STACK_MARGIN = 64;    { Stack size margin for stack checking }
+{$else}
   STACK_MARGIN = 16384;    { Stack size margin for stack checking }
+{$endif}
 { Random / Randomize constants }
   OldRandSeed : Cardinal = 0;