Sorry about that. I used 2 and it failed (though in
another program). Also the regular assignment failed
as well. (couldn't find it in your asm output)
OK: here's my code:
#include <sys.h>
#include <serial.h>
#include <rs232.h>
#include <string.h>
#include "printf.h"
#include "vt100.h"
struct unaligned {
char first;
int second;
} __attribute__((packed));
union test {
struct unaligned data;
char cdata[3];
};
void start_app() {
union test test;
int data, tmp;
test.cdata[0] = 0x1;
test.cdata[1] = 0x2;
test.cdata[2] = 0x3;
data = test.data.second;
memcpy(&tmp, &test.data.second, 2);
while (1) {
printf("%x %x %x\r\n", test.data.second, data, tmp);
sys_delay(100);
}
}
This gives me the following asm:
* Function `start_app'
***********************/
start_app:
/* prologue: frame size = 4 */
.L__FrameSize_start_app=0x4
.L__FrameOffset_start_app=0x6
push r11
sub #4, r1 ; 4, fpn 0
/* prologue end (size=2) */
mov.b #llo(1), @r1
mov.b #llo(2), 1(r1)
mov.b #llo(3), 2(r1)
mov 1(r1), r11 ; FAILS because not aligned
.L5: ; (is regular assignment)
push r11
push r11
push 2+5(r1)
push #.LC0
call #printf
mov #llo(100), r15
call #sys_delay
add #llo(8), r1
jmp .L5
I'm not sure where the memcpy went though
G Halkes
--- Dmitry <[email protected]> wrote:
>
> oops...
> you should pass a copy size to memcpy() as third
> parameter.
> I passed 3.
> From the output I see everything is correct:
> main:
> /* prologue: frame size = 6 */
> .L__FrameSize_main=0x6
> .L__FrameOffset_main=0x6
> mov #(__stack-6), r1
> /* prologue end (size=2) */
> ;; allocate test structure on stack
> mov.b #llo(1), @r1 ; load 0x01
> mov.b #llo(2), 1(r1) ; load 2
> mov.b #llo(3), 2(r1) ; load 3
> mov r1, r15 ;
> add #llo(4), r15 ; prepare
> destination pointer
> mov r1, r14 ; load r14 with a
> pointer to test.data
> add #llo(1), r14 ; skip 'first' in
> test.data
> mov.b @r14+, 4(r1) ; copy this.
> mov.b @r14+, 1(r15) ; three
> mov.b @r14+, 2(r15) ; times
> /* epilogue: frame size=6 */
> add #6, r1
> br #__stop_progExec__
> /* epilogue end (size=4) */
> /* function main size 23 (17) */
>
>
>
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