Hello,
Thank you very much for both Matthias and Sergey for your kind responses.
Best Regards,
..:: කසුන් චන්ද්රනාත් ::..
..:: Kasun Chandranath ::..
Matthias Hartmann wrote:
> Thanks to Sergey for analysing the LST file.
>
> So, having a MCU with Von Neumann architecture is a good thing here ;-)
> No spezial handling needed to optimize for RAM usage.
>
>
> 2009/3/25 Sergey A. Borshch <sb...@us...>:
>> Kasun Hewage wrote:
>>> It seems, this can not be done or no point of doing it in MSP430 MCUs
>>> because they are Von Neumann architecture MCUs. Would you be able to
>>> tell me that how can I gain an optimized RAM usage when dealing with
>>> constant strings.
>> Take a look at list file for simple example:
>>
>> __attribute__((noreturn))int main()
>> {
>> WDTCTL = WDTPW;
>> send_string("Hello I am Kasun", 17);
>> for(;;);
>> }
>>
>> .text
>> 143 .LC0:
>> 144 0000 4865 6C6C .string "Hello I am Kasun"
>> 144 6F20 4920
>> 144 616D 204B
>> 144 6173 756E
>> 144 00
>> 145 .section .text.main,"ax",@progbits
>> 146 .p2align 1,0
>> 147 .global main
>> 149 /***********************
>> 150 * Function `main'
>> 151 ***********************/
>> 152 main:
>> 153 .LFB4:
>> 154 .LSM10:
>> 155 /* prologue: frame size = 0 */
>> 156 .L__FrameSize_main=0x0
>> 157 .L__FrameOffset_main=0x4
>> 158 0000 3140 0000 mov #(__stack-0), r1
>> 159 0004 0441 mov r1,r4
>> 160 /* prologue end (size=3) */
>> 161
>> 162 .LSM11:
>> 163 0006 B240 005A mov #llo(23040), &0x0120
>> 163 2001
>> 164 .LSM12:
>> 165 000c 3E40 1100 mov #llo(17), r14
>> 166 0010 3F40 0000 mov #.LC0, r15 ; <--- here
>> 167 0014 B012 0000 call #send_string
>> 168 .LSM13:
>> 169 .L9:
>> 170 0018 FF3F jmp .L9
>> 171 .LSM14:
>> 172
>> 173 /* epilogue: empty, noreturn function*/
>> 174 .LFE4:
>> 176
>> 177 /********* End of function ******/
>>
>> As you can see, string located in .text region and send_string gets pointer
>> directly to this location (; <--- here), with no intermediate copy to ram.
>>
>> --
>> Regards,
>> Sergey A. Borshch mailto: sb...@so...
>> SB ELDI ltd. Riga, Latvia
>>
