* i8086 small and tiny memory model ppus made incompatible. Rationale:

  o the maintenance effort will be less - previously we had to test 4
    combinations:
      tiny program with tiny rtl
      tiny program with small rtl
      small program with tiny rtl
      small program with small rtl
    I only tested both tiny and small programs with the small rtl, so I missed
    a bug, which caused small programs built with the tiny rtl to always give
    a "Nil pointer assignment" error. Now we only need to test two cases:
      tiny program with tiny rtl
      small program with small rtl
  o I'm planning a bug fix for interrupt procedures in the tiny model, which
    will make their prolog differ between small and tiny. Currently, they're
    not used in the rtl, but that may change. And even if it doesn't,
    interrupt procedures may also be used by user units.

git-svn-id: trunk@27516 -

compiler/fppu.pas

@@ -256,6 +256,14 @@ var
            Message(unit_u_ppu_invalid_memory_model,@queuecomment);
            exit;
          end;
+        if ((ppufile.header.flags and uf_i8086_cs_equals_ds)<>0) xor
+            (current_settings.x86memorymodel=mm_tiny) then
+         begin
+           ppufile.free;
+           ppufile:=nil;
+           Message(unit_u_ppu_invalid_memory_model,@queuecomment);
+           exit;
+         end;
 {$endif i8086}
 {$ifdef cpufpemu}
        { check if floating point emulation is on?
@@ -1095,6 +1103,8 @@ var
            flags:=flags or uf_i8086_far_data;
          if current_settings.x86memorymodel=mm_huge then
            flags:=flags or uf_i8086_huge_data;
+         if current_settings.x86memorymodel=mm_tiny then
+           flags:=flags or uf_i8086_cs_equals_ds;
 {$endif i8086}
 {$ifdef cpufpemu}
          if (cs_fp_emulation in current_settings.moduleswitches) then

compiler/ppu.pas

@@ -165,6 +165,7 @@ const
   uf_i8086_far_code     = $2000000; { this unit uses an i8086 memory model with far code (i.e. medium, large or huge) }
   uf_i8086_far_data     = $4000000; { this unit uses an i8086 memory model with far data (i.e. compact or large) }
   uf_i8086_huge_data    = $8000000; { this unit uses an i8086 memory model with huge data (i.e. huge) }
+  uf_i8086_cs_equals_ds = $10000000; { this unit uses an i8086 memory model with CS=DS (i.e. tiny) }
 
 {$ifdef generic_cpu}
 { We need to use the correct size of aint and pint for

compiler/utils/ppuutils/ppudump.pp

@@ -475,7 +475,7 @@ type
     str  : string[30];
   end;
 const
-  flagopts=27;
+  flagopts=28;
   flagopt : array[1..flagopts] of tflagopt=(
     (mask: $1    ;str:'init'),
     (mask: $2    ;str:'final'),
@@ -505,7 +505,8 @@ const
     (mask: $1000000 ;str:'has_resstrinits'),
     (mask: $2000000 ;str:'i8086_far_code'),
     (mask: $4000000 ;str:'i8086_far_data'),
-    (mask: $8000000 ;str:'i8086_huge_data')
+    (mask: $8000000 ;str:'i8086_huge_data'),
+    (mask: $10000000;str:'i8086_cs_equals_ds')
   );
 var
   i,ntflags : longint;