Mail Archives: djgpp-workers/1996/08/06/11:46:46
I have tested the following test program to build with the
binutils 2.7 and it works.
---------------------test.c------------------
#include <stdio.h>
unsigned char Tableau[1024L*1024L*16L];
int main(int argc, char * argv[])
{
printf("hello world\n");
return(0);
}
---------------------------------------------
I have tested it also with lage libraries. (I think the
Turbo Vision library, compiled with -g3, which contains
about 16000 symbols and is about 4 MB large).
But I found an other difference between GAS 2.5.2 and
GAS 2.7. I have compiled the above test program with
-S to get the assembler file. Then I have compiled it
with the two assemblers and got the following results:
----------compiled with GAS 2.5.2---------------
GAS LISTING test.s page 1
1 .file "test.c"
2 gcc2_compiled.:
3 ___gnu_compiled_c:
4 .text
5 LC0:
6 0000 68656C6C .ascii "hello world\12\0"
6 6F20776F
6 726C640A
6 00
7 000d 909090 .align 2
8 .globl _main
9 _main:
10 0010 55 pushl %ebp
11 0011 89E5 movl %esp,%ebp
12 0013 E8E8FFFF call ___main
12 FF
13 0018 68000000 pushl $LC0
13 00
14 001d E8DEFFFF call _printf
14 FF
15 0022 31C0 xorl %eax,%eax
16 0024 C9 leave
17 0025 C3 ret
18 0026 9090 .comm _Tableau,16777216
------------------------------------------------------
------------compiled with GAS 2.7---------------------
GAS LISTING test.s page 1
1 .file "test.c"
2 gcc2_compiled.:
3 ___gnu_compiled_c:
4 .text
5 LC0:
6 0000 68656C6C .ascii "hello world\12\0"
6 6F20776F
6 726C640A
6 00
7 000d 90 .align 2
8 .globl _main
9 _main:
10 000e 55 pushl %ebp
11 000f 89E5 movl %esp,%ebp
12 0011 E8EAFFFF call ___main
12 FF
13 0016 68000000 pushl $LC0
13 00
14 001b E8E0FFFF call _printf
14 FF
15 0020 31C0 xorl %eax,%eax
16 0022 C9 leave
17 0023 C3 ret
18 .comm _Tableau,16777216
-----------------------------------------------------
As you can see, there is a difference in aligning the code.
Now my question. Which is the correct? What should '.align 2'
mean? (alignment on a 2 byte boundory or on a boundary with
the last 2 bits zero?)
Robert
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