C podozrenie na bug compilera

[Jan Waclawek]

V tom disassembleri nevidim ziadny zasadnejsi problem; samozrejme zalezi na
hodnote stack pointra (co zrejme ukazuje na zaciatok predtym vytvoreneho
stack frame) a registra r4 (ktory zase zrejme ukazuje na pole buf[]); ale
silne pochybujem, ze by tam bol nejaky problem.

Skor verim tomu, ze kecia nastroj, ktorym to pozerate, ci je to uz
simulator alebo nejaky iny debugger. Skuste nejaku nezavislu metodu -
poslat hodnotu premennej cez seriak do PC, vypisat ho na nejaky pripojeny
displej, alebo take nieco.

wek


----- Original Message ---------------

>Keil MDK470a
>    uint16_t radress, rquantity;
>
>    buf[0] = 0x87;
>    buf[1] = 0x65;
>    buf[2] = 0x43;
>    buf[3] = 0x21;
>    radress = (uint16_t)buf[0] << 8;
>    radress |= buf[1];
>    rquantity = (uint16_t)buf[2] << 8;
>    rquantity |= buf[3];
>
>prelozil ako:
>   382:         buf[0] = 0x87;
>0x08000B82 2087      MOVS     r0,#0x87
>0x08000B84 7020      STRB     r0,[r4,#0x00]
>   383:         buf[1] = 0x65;
>0x08000B86 2065      MOVS     r0,#0x65
>0x08000B88 7060      STRB     r0,[r4,#0x01]
>   384:         buf[2] = 0x43;
>0x08000B8A 2043      MOVS     r0,#0x43
>0x08000B8C 70A0      STRB     r0,[r4,#0x02]
>   385:         buf[3] = 0x21;
>0x08000B8E 2021      MOVS     r0,#0x21
>0x08000B90 70E0      STRB     r0,[r4,#0x03]
>   386:         radress = (uint16_t)buf[0] << 8;
>0x08000B92 7820      LDRB     r0,[r4,#0x00]
>0x08000B94 0200      LSLS     r0,r0,#8
>0x08000B96 9003      STR      r0,[sp,#0x0C]
>   387:         radress |= buf[1];
>0x08000B98 7860      LDRB     r0,[r4,#0x01]
>0x08000B9A 9903      LDR      r1,[sp,#0x0C]
>0x08000B9C 4308      ORRS     r0,r0,r1
>0x08000B9E 9003      STR      r0,[sp,#0x0C]
>   388:         rquantity = (uint16_t)buf[2] << 8;
>0x08000BA0 78A0      LDRB     r0,[r4,#0x02]
>0x08000BA2 0205      LSLS     r5,r0,#8
>   389:         rquantity |= buf[3];
>0x08000BA4 78E0      LDRB     r0,[r4,#0x03]
>0x08000BA6 4305      ORRS     r5,r5,r0
>
>rquantity je OK, radress hodnota 0x0001
>MCU core cortex M0
>
>Jan Waclawek  wrote / napísal(a):
>> Aky kompilator, aka verzia, ake su command-line options, ako vyzera
>> disassembly funkcie?
>>
>> wek
>>
>>
>>
>> ----- Original Message ---------------
>>
>>
>>
>>   
>>> Zdravim konferenci, mam nasledovny problem:
>>>
>>> void funkcia (uint8_t *buf, uint8_t len, uint32_t *coils){
>>>    uint16_t radr;
>>>    radr = buf[0];
>>>    ...
>>> }
>>>
>>> A v debuggeri do radr priradi 0x0102, cize 16bit cislo. Optimalizacie su 
>>> vypnute a priznam sa, nechapem.
>>> Ako je nieco take vobec mozne?
>>>     
>>