Structure alignment problem

[Rosetti Andrea]

Hi All,

I use cygnus-2.7.2-960126 cross compiler version.
This is the official version provided by WindRiver Tornado distribution.

My problem is to set the max alignment size for the structure members
because I use different compilers for different targets
and I have compatibility problems.

For example:

struct {
 int a;
 char b;
 int c;
} pippo;

void bye ()
{
  pippo.a=4;
  pippo.b='4';
  pippo.c=9;

}

with Microtec MRI for 68xxx:

; Microtec(R) Research Inc. 68K C Compiler 4.2D
; Host Operating System - SUN4 UNIX
; Command Line Options Specified:
;  -Ri/tmp/prova.1 -v prova.c

 TTL prova.c
; MCC68K 4.2D   S4090391 s42206
 OPT NOABSPCADD,E,CASE
 NAME prova
 XCOM _pippo,10
 SECTION code,,C
 XDEF _bye
_bye:
 moveq #4,d0
 move.l d0,_pippo
 move.b #52,_pippo+4
 moveq #9,d0
 move.l d0,_pippo+6  <---
 rts
;  code: 26 bytes   stack: 0 bytes
 END
------------------------------

with Diab Data (X76=2, X88=2)

 .align  2
 .globl  bye
bye:
 stwu  r1,-8(r1)
 mfspr  r0,lr
 stw  r0,12(r1)
#$$ee
 addis  r12,r0,pippo@ha
 addi  r11,r0,4
 stw  r11,pippo@l(r12)
 addis  r10,r0,(pippo+4)@ha
 addi  r9,r0,52
 stb  r9,(pippo+4)@l(r10)
 addis  r12,r0,(pippo+6)@ha
 addi  r11,r0,9
 stw  r11,(pippo+6)@l(r12)  <---
#$$be
 lwz  r0,12(r1)
 mtspr  lr,r0
 addi  r1,r1,8
#$$tl 0x0 0x0
 blr
#$$ef
 .type  bye,@function
 .size  bye,.-bye

# Allocations for bye

# Allocations for module
--------------------

with gcc (GNU C version cygnus-2.7.2-960126 PowerPC Embedded)

 # GNU C cygnus-2.7.2-960126
 # -fpeephole -ffunction-cse -fkeep-static-consts -fpcc-struct-return
-fcommon
 # -fgnu-linker -mpowerpc -mnew-mnemonics

 .file "prova.c"
gcc2_compiled.:
 .section ".text"
 .align 2
 .globl bye
 .type  bye,@function
bye:
 stwu 1,-16(1)
 stw 31,12(1)
 mr 31,1
 addis 9,0,pippo@ha
 addi 11,9,pippo@l
 li 0,4
 stw 0,0(11)
 addis 9,0,pippo@ha
 addi 11,9,pippo@l
 li 0,52
 stb 0,4(11)
 addis 9,0,pippo@ha
 addi 11,9,pippo@l
 li 0,9
 stw 0,8(11)  <--
.L1:
 lwz 11,0(1)
 lwz 31,-4(11)
 mr 1,11
 blr
.Lfe1:
 .size  bye,.Lfe1-bye
 .comm pippo,12,4
 .ident "GCC: (GNU) cygnus-2.7.2-960126"


Sorry for my poor english.
Thank you.

Ciao
Andrea


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