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Hi everybody,

I'm new to arduino and the forum and this is my first post. I hope I'm posting it in the right forum...

I started with my first project and my binary excess the maximum size to fit in the atmega168, so I had a look at the object files in the /applet folder of my sketch with avr-objdump and found something I think is weird. The constructors of every class are duplicated, they are created twice.

For example, if I do "avr-objdump -CD my_sketch.elf" I can see this for the HardwareSerial class:
Code:
000022c0 <HardwareSerial::HardwareSerial(unsigned char)>:
    22c0:       08 95           ret

000022c2 <HardwareSerial::HardwareSerial(unsigned char)>:
    22c2:       08 95           ret

000022c4 <HardwareSerial::printNumber(unsigned long, unsigned char)>:
    22c4:       cb 01           movw    r24, r22
    22c6:       ba 01           movw    r22, r20
    22c8:       33 27           eor     r19, r19
    22ca:       44 27           eor     r20, r20
    22cc:       55 27           eor     r21, r21
    22ce:       0e 94 e6 12     call    0x25cc  ; 0x25cc <printIntegerInBase>
    22d2:       08 95           ret
...

You can see that the HardwareSerial constructor is duplicated, and I think this is wasting space, not much in this case, but if I look for one class with a more complex contructor this is worse:

Code:
0000010a <LCD4Bit::LCD4Bit(int)>:
     10a:       70 93 0f 01     sts     0x010F, r23
     10e:       60 93 0e 01     sts     0x010E, r22
     112:       61 50           subi    r22, 0x01       ; 1
     114:       70 40           sbci    r23, 0x00       ; 0
     116:       62 30           cpi     r22, 0x02       ; 2
     118:       71 05           cpc     r23, r1
     11a:       30 f0           brcs    .+12            ; 0x128 <LCD4Bit::LCD4Bit(int)+0x1e>
     11c:       81 e0           ldi     r24, 0x01       ; 1
     11e:       90 e0           ldi     r25, 0x00       ; 0
     120:       90 93 0f 01     sts     0x010F, r25
     124:       80 93 0e 01     sts     0x010E, r24
     128:       08 95           ret

0000012a <LCD4Bit::LCD4Bit(int)>:
     12a:       70 93 0f 01     sts     0x010F, r23
     12e:       60 93 0e 01     sts     0x010E, r22
     132:       61 50           subi    r22, 0x01       ; 1
     134:       70 40           sbci    r23, 0x00       ; 0
     136:       62 30           cpi     r22, 0x02       ; 2
     138:       71 05           cpc     r23, r1
     13a:       30 f0           brcs    .+12            ; 0x148 <LCD4Bit::LCD4Bit(int)+0x1e>
     13c:       81 e0           ldi     r24, 0x01       ; 1
     13e:       90 e0           ldi     r25, 0x00       ; 0
     140:       90 93 0f 01     sts     0x010F, r25
     144:       80 93 0e 01     sts     0x010E, r24
     148:       08 95           ret

0000014a <LCD4Bit::pulseEnablePin()>:
     14a:       1f 93           push    r17
     14c:       61 e0           ldi     r22, 0x01       ; 1
     14e:       80 91 04 01     lds     r24, 0x0104
     152:       0e 94 52 15     call    0x2aa4  ; 0x2aa4 <digitalWrite>
     156:       15 e0           ldi     r17, 0x05       ; 5

I think the constructors should appear only once and this is wasting some of the limited space in the atmega168.

Does anyone know why this is happening? Is it normal?
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hey thanks for th report
we'll have a look at it... if it does it in every program then it could be a bug in the compiler...


massimo
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I have tried with some of the examples that comes with arduino and I the result is the same, so I think the problem is not related to my sketch.

Can someone test it on his/her system to check if the problem is related to my compiler/system or is a general problem?

Thanks.
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Same on my system (arduino-0010 on XP). Two hardware serial constructors in the asciitable communication example sketch.

BTW, is there an easy way to run objdump on the current sketch from the IDE?
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I don't know how to run objdump from the IDE.

I forgot to mention I'm using arduino-0010 on a Debian GNU/Linux system and avr-gcc v4.2.3
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I found a bug already logged for gcc http://gcc.gnu.org/bugzilla/show_bug.cgi?id=3187. It looks like a quite old issue with a long discussion. Although this issue may not be very important in some situations I think is pretty important for embedded systems.

I read on the discussion that there was a patch to solve this that was never approved, I'll have a look at this to see if it can be helpful to reduce the size of arduino sketchs.
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