.data?
data01 db 1073741824 dup(?)
data02 db 1073741824 dup(?)
.code
main PROC SYSTEMV _argc:DWORD, _argv:QWORD
xor rax,rax
ret
main ENDP
end
linux: 6963 Segmentation fault
.data?
data01 db 1073741824 dup(?)
data02 db 1073741824 dup(?)
.code
entry_point proc
XOR RAX,RAX
ret
entry_point endp
end
windows: 00000005
Are there limits to BSS, How can I use 4 GB?
Hi mabdelouahab,
Why not to use dynamic memory allocation functions?
.data?
data01 QWORD ?
invoke GlobalAlloc,GMEM_ZEROINIT,1073741824
mov data01,rax
Thank you Vortex, I know the allocation dynamically , But my question is about the limits of BSS
invoke g_malloc,16032385536
mov view,rax
mov rcx,16032385536-32
add rax,rcx
mov dword ptr [rax],"DCBA"
mov dword ptr [rax+4],"HGFE"
mov qword ptr [rax+8],0
invoke printf,str$(<13,10,"0%Xh='%s' ">),rax ,rax
Quote07D5C69F0h='ABCDEFGH'
16GB
Its been my experience that large amount bss can be compiled, but it takes forever for the assembler to do it.
Quote from: BugCatcher on September 11, 2020, 12:38:11 AM
Its been my experience that large amount bss can be compiled, but it takes forever for the assembler to do it.
This was true for older versions of MASM.
Hi mabdelouahab,
No any error messages in my test :
.data?
data01 db 1073741824 dup(?)
data02 db 1073741824 dup(?)
.code
entry_point proc
XOR RAX,RAX
ret
entry_point endp
end
uasm64.exe -win64 test.asm
UASM v2.49, Jun 21 2019, Masm-compatible assembler.
Portions Copyright (c) 1992-2002 Sybase, Inc. All Rights Reserved.
Source code is available under the Sybase Open Watcom Public License.
test.asm: 9 lines, 2 passes, 2 ms, 0 warnings, 0 errors
Vortex ,
After running: 00000005 (windows) or 6963 Segmentation fault (linux)
hello sir mabdelouahab, these are my tests in linux 64
test2.uasm
;uasm -elf64 -pie test2.uasm
;ld test2.o -o test2
;./test2 ; echo $?
.X64
option casemap:none
.data?
data01 db 7FFFFFFFh dup(?)
data02 db 7FFFFFFFh dup(?)
.code
_start:
mov rdi,0 ;return code
mov rax,60 ;sysexit
syscall
end _start
;---first try
; data01 db 80000000h dup(?) ;Error A2209: Count must be positive or zero
;---second try
; data01 db 7FFFFFFFh dup(?) ;OK to assemble, link and execute
;---third try
; data01 db 7FFFFFFFh dup(?) ;pseudo OK to assemble, link and execute
; data02 db 7FFFFFFFh dup(?)
;readelf -S test2.o
; [ 3] .bss NOBITS 0000000000000000 00000210
; fffffffffffffffe 0000000000000000 WA 0 0 16
;readelf -S test2
; No bss section created in executable
;size test2
; text data bss dec hex filename
; 16 0 0 16 10 test2
;size test2.o
; text data bss dec hex filename
; 16 0 18446744073709551614 14 e test2.o
;fourth try, using previous test.o and changing with hexadecimal editor fffffffffffffffeh at offset 120h
;to FF FF FF FF │ 00 00 00 00
;link OK, execute OK
; [ 3] .bss NOBITS 0000000000000000 00000210 object file
; 00000000ffffffff 0000000000000000 WA 0 0 16
;[ 2] .bss NOBITS 0000000000402000 00002000 executable
; 0000000100000000 0000000000000000 WA 0 0 16
;fifth try, using previous test.o and changing with hexadecimal editor FF FF FF FF │ 00 00 00 00 at offset 120h
;to 00 00 00 00 │ 10 00 00 00
;link OK, execute return 139 segmentation fault
;[ 3] .bss NOBITS 0000000000000000 00000210
; 0000001000000000 0000000000000000 WA 0 0 16
;strace ./test2 ; echo $?
;execve("./test2", ["./test2"], 0x7ffc150b9e40 /* 65 vars */) = -1 ENOMEM (Not possible to alloc memory)
;+++ killed by SIGSEGV +++
So I try with as assembler same tests and increasing allocation data:
test3.s
#as test3.s -o test3.o
#ld -e _start test3.o -o test3
#./test3 ; echo$?
.code64
.intel_syntax noprefix
.bss
data01: .space 0x40fffffff
.text
.global _start
_start:
mov rdi,0
mov rax,60
syscall
I was thinking in elf64 field but thats 64 bits, so not a problem. After I think in 48 bits addressing of some machines or hardware limitation of some machines. After I think in some link switches but was not able to find anything; so I check ld loader, ... . But when I tried with as assembler I see that can be done.
Maybe some field in object file.