From 73d7f2aa18807e3fbca99b2c214bda48250a555b Mon Sep 17 00:00:00 2001
From: nickysn <nickysn@gmail.com>
Date: Sun, 8 Jun 2014 21:14:57 +0000
Subject: [PATCH] * let the compiler generate the stack segment in i8086 near
data memory models as well. Even though, in these models, the stack is
dynamically allocated (because it goes on top of the heap, but the heap is
variable size), there are still benefits: 1) the program will run on a
larger stack during initialization, before the actual stack (and heap)
are ready 2) in cases, when the system is extremely low on memory, DOS will
reject to load the program if there's not enough memory for the stack
the program requires. This way the startup code can be further
simplified by omitting the 'not enough memory' check in the future (when
we add the minimum heap size to the executable reserved space as well).
git-svn-id: trunk@27903 -
---
compiler/i8086/n8086util.pas | 4 ++--
compiler/x86/agx86nsm.pas | 7 ++-----
rtl/msdos/prt0comn.asm | 7 ++++---
3 files changed, 8 insertions(+), 10 deletions(-)
diff --git a/compiler/i8086/n8086util.pas b/compiler/i8086/n8086util.pas
index a8b83bbcd3..da19bfebf9 100644
--- a/compiler/i8086/n8086util.pas
+++ b/compiler/i8086/n8086util.pas
@@ -47,8 +47,7 @@ implementation
class procedure ti8086nodeutils.InsertMemorySizes;
begin
inherited;
- if current_settings.x86memorymodel in x86_far_data_models then
- InsertStackSegment;
+ InsertStackSegment;
end;
@@ -73,6 +72,7 @@ implementation
dec(stacksizeleft,stackblock);
inc(i);
end;
+ current_asmdata.asmlists[al_globals].concat(tai_symbol.Createname_global('___stacktop',AT_DATA,0));
end;
diff --git a/compiler/x86/agx86nsm.pas b/compiler/x86/agx86nsm.pas
index 0d32d96a40..35c1054a37 100644
--- a/compiler/x86/agx86nsm.pas
+++ b/compiler/x86/agx86nsm.pas
@@ -1226,16 +1226,13 @@ interface
AsmWriteLn('SECTION .fpc');
{ WLINK requires class=bss in order to leave the BSS section out of the executable }
AsmWriteLn('SECTION .bss class=bss');
- if current_settings.x86memorymodel in x86_far_data_models then
+ if current_settings.x86memorymodel<>mm_tiny then
AsmWriteLn('SECTION stack stack class=stack align=16');
{ group these sections in the same segment }
if current_settings.x86memorymodel=mm_tiny then
AsmWriteLn('GROUP dgroup text rodata data fpc bss')
else
- if current_settings.x86memorymodel in x86_far_data_models then
- AsmWriteLn('GROUP dgroup rodata data fpc bss stack')
- else
- AsmWriteLn('GROUP dgroup rodata data fpc bss');
+ AsmWriteLn('GROUP dgroup rodata data fpc bss stack');
if paratargetdbg in [dbg_dwarf2,dbg_dwarf3,dbg_dwarf4] then
begin
AsmWriteLn('SECTION .debug_frame use32 class=DWARF');
diff --git a/rtl/msdos/prt0comn.asm b/rtl/msdos/prt0comn.asm
index c5fb06b773..c968eb5a16 100644
--- a/rtl/msdos/prt0comn.asm
+++ b/rtl/msdos/prt0comn.asm
@@ -56,6 +56,9 @@
%ifdef __FAR_DATA__
extern ___stack
%endif
+%ifdef __NEAR_DATA__
+ extern ___stacktop
+%endif
extern __SaveInt00
@@ -72,7 +75,7 @@
%ifdef __NEAR_DATA__
; init the stack
mov ss, bx
- mov sp, stacktop
+ mov sp, ___stacktop wrt dgroup
%endif
%endif
@@ -475,8 +478,6 @@ __nullarea:
%ifdef __NEAR_DATA__
segment stack stack class=stack
- resb 256
- stacktop:
%else
segment data
; add reference to the beginning of stack, so the object module,