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 Posted: Jul 19, 2012 - 11:35 AM |
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Joined: Nov 13, 2009
Posts: 104
Location: Russia, Yekatherinburg
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Hi!
I use (with -O2 option) GCC from WinAVR 20090313 version 4.3.2.
Code:
unsigned char *p;
unsigned short pp;
cli();
34e: f8 94 cli
p = RingPointer;
350: f2 01 movw r30, r4
*p ++ = 0xFF;
352: d2 01 movw r26, r4
354: 8f ef ldi r24, 0xFF ; 255
356: 8d 93 st X+, r24
*p ++ = 0x04;
358: 84 e0 ldi r24, 0x04 ; 4
35a: 81 83 std Z+1, r24 ; 0x01
35c: fd 01 movw r30, r26
35e: 31 96 adiw r30, 0x01 ; 1
*p ++ = from;
360: 11 96 adiw r26, 0x01 ; 1
362: 2c 93 st X, r18
*p ++ = to;
364: 61 83 std Z+1, r22 ; 0x01
366: 32 96 adiw r30, 0x02 ; 2
pp = (unsigned short)p;
if ( (pp >> 8) == ((RAM_END - 0x100) >> 8) ) p = ring_start;
RingPointer = p;
368: 2f 01 movw r4, r30
sei();
36a: 78 94 sei
Code:
register unsigned char * RingPointer asm( "r4" );
unsigned char * volatile ring_start = (unsigned char*) RAM_START;
Where is
Code:
if ( (pp >> 8) == ((RAM_END - 0x100) >> 8) ) p = ring_start;
?!
Does it work in new version of GCC? What with register variables in newer version of GCC?
Ilya
ps: This is work:
Code:
if ( (pp & 0xFF00) == ((RAM_END - 0x100) & 0xFF00) ) p = ring_start;
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Posted: Jul 19, 2012 - 11:37 AM |
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Joined: Jul 18, 2005
Posts: 62354
Location: (using avr-gcc in) Finchingfield, Essex, England
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| You haven't shown enough context - the code could easily have been moved to before or after the sequence you posted. Post more of the .lss and note that I'm going to edit your thread title. |
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Posted: Jul 19, 2012 - 11:57 AM |
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Joined: Nov 13, 2009
Posts: 104
Location: Russia, Yekatherinburg
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Hi, clawson!
clawson wrote:
You haven't shown enough context - the code could easily have been moved to before or after the sequence you posted.
No, I checked it.
clawson wrote:
Post more of the .lss
Ok.
Code:
WaitForReply = 0;
304: 10 92 04 01 sts 0x0104, r1
308: 08 95 ret
[skiped]
{
unsigned char *p;
unsigned short pp;
cli();
34e: f8 94 cli
p = RingPointer;
350: f2 01 movw r30, r4
*p ++ = 0xFF;
352: d2 01 movw r26, r4
354: 8f ef ldi r24, 0xFF ; 255
356: 8d 93 st X+, r24
*p ++ = 0x04;
358: 84 e0 ldi r24, 0x04 ; 4
35a: 81 83 std Z+1, r24 ; 0x01
35c: fd 01 movw r30, r26
35e: 31 96 adiw r30, 0x01 ; 1
*p ++ = from;
360: 11 96 adiw r26, 0x01 ; 1
362: 2c 93 st X, r18
*p ++ = to;
364: 61 83 std Z+1, r22 ; 0x01
366: 32 96 adiw r30, 0x02 ; 2
pp = (unsigned short)p;
if ( (pp >> 8) == ((RAM_END - 0x100) >> 8) ) p = ring_start;
RingPointer = p;
368: 2f 01 movw r4, r30
sei();
36a: 78 94 sei
36c: cb cf rjmp .-106 ; 0x304 <ProcTel+0x30>
}
Code:
#define RAM_START 0x1100
#define RAM_END (RAM_START + 0x7FFF)
register unsigned char * RingPointer asm( "r4" );
unsigned char * volatile ring_start = (unsigned char*) RAM_START;
void ProcTel( unsigned char from, unsigned char to, unsigned char fc );
If RAM_END redefine as 'RAM_START + 0x8000' then it work fine.
And this is work too:
Code:
#if defined(__ASSEMBLER__)
#define RAM_START 0x1100
#define RAM_END (RAM_START + 0x7FFF)
#else
#define RAM_START 0x1100u
#define RAM_END (RAM_START + 0x7FFFu)
#endif
But I don't like double define same constants for asm and C...
clawson wrote:
and note that I'm going to edit your thread title.
Ok, no matter 
Ilya |
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Posted: Jul 19, 2012 - 12:13 PM |
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Joined: Dec 21, 2006
Posts: 1485
Location: Saar-Lor-Lux
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| [quote="501-q"]Where is
Code:
if ( (pp >> 8) == ((RAM_END - 0x100) >> 8) ) p = ring_start;
Make sure you don't compare unsigned against signed. Enable warnings and fix them.
Quote:
Does it work in new version of GCC? What with register variables in newer version of GCC?
Yes, you can use R2..R7 as global registers.
Compile every module with -ffixed2 -ffixed-3 ... including modules contributing to libraries or make otherwise sure that no module unintentionally uses one of your global regs.
Moreover, notice that GCC can optimize global registers: global registers cannot be volatile; volatile only applies to memory storage classes, not to register.
This can lead to problems if you share a global reg between different IRQ levels. |
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Posted: Jul 19, 2012 - 12:17 PM |
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Joined: Nov 13, 2009
Posts: 104
Location: Russia, Yekatherinburg
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And this is work too:
Code:
if ( (pp >> 8) == ((RAM_END - 0x100u) >> 8) ) p = ring_start;
With this:
Code:
#define RAM_START 0x1100
#define RAM_END (RAM_START + 0x7FFF)
Problem was with compare between signed and unsigned shorts. But I don't undestand GCC's logic in this case.
WBR, Ilya. |
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Posted: Jul 19, 2012 - 12:28 PM |
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Joined: Nov 13, 2009
Posts: 104
Location: Russia, Yekatherinburg
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Hi, SprinterSB!
SprinterSB wrote:
501-q wrote:
Where is
Code:
if ( (pp >> 8) == ((RAM_END - 0x100) >> 8) ) p = ring_start;
Make sure you don't compare unsigned against signed. Enable warnings and fix them.
Yes, there is warning in this line:
Code:
pb.c:143: warning: integer overflow in expression
But this warning exist in both cases: when it work and when it isn't work.
To fix this warning I have to double define same constants (but I don't like it):
Code:
#if defined(__ASSEMBLER__)
#define RAM_START 0x1100
#define RAM_END (RAM_START + 0x7FFF)
#else
#define RAM_START 0x1100u
#define RAM_END (RAM_START + 0x7FFFu)
#endif
Ilya |
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Posted: Jul 19, 2012 - 12:34 PM |
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Joined: Dec 21, 2006
Posts: 1485
Location: Saar-Lor-Lux
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Posted: Jul 19, 2012 - 12:48 PM |
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Joined: Nov 13, 2009
Posts: 104
Location: Russia, Yekatherinburg
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SprinterSB wrote:
Isn't RAMEND defined in avr/io.h?
I use RAM_END as end of external RAM. All of external ram I use as ring buffer (in this case).
(ring_start need too: I wait for some event and then save part of ring buffer, change ring_start and wait same event again).
Ilya |
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