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joshkeys
Joined: 16 Aug 2005
Posts: 37
Location: Fredericton,NB
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| Unwanted Automated ASM code |
 Posted: Thu Dec 14, 2006 12:48 pm |
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Hello all,
I have been using ASM code throughout my programs to get certain aspects of my code more efficient. The problem I am running into is that when i compile, the compiler inserts unecessary ASM lines that I dont want, such as is shown below.
| Code: |
.................... BSF 0x05.2
0076: BCF 03.5
0077: BSF 05.2
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The problem here is that I do not want it to set the bank to bank 0 because I have already done this a few lines before and the status register is still set to bank 0. But yet it sets it for me, and also at the end of a while statement, it goes ahead and sets teh status register to bank 0 again. I am really desperate for CPU cycles here and would like to save as many as possbile. so how can i stop it from doing this. Thanks
Josh[/code] |
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drh
Joined: 12 Jul 2004
Posts: 192
Location: Hemet, California USA
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| Posted: Thu Dec 14, 2006 1:42 pm |
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Are you using #asm...#endasm directives?
If so, using #asm ASIS will stop the compiler
from setting the banks.
_________________
David |
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joshkeys
Joined: 16 Aug 2005
Posts: 37
Location: Fredericton,NB
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| Posted: Thu Dec 14, 2006 1:48 pm |
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yes, I use #asm and #endasm. It still decides to add a line when it feels like to make sure the proper bank has been set.
Josh |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Dec 14, 2006 2:57 pm |
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| Quote: |
yes, I use #asm and #endasm. It still decides to add a line when it feels like to make sure the proper bank has been set.
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I tested the ASIS directive with PCM vs. 3.249 and I found that it is
effective in preventing the compiler from putting in bank switching code.
Here is the result with ASIS. There's no bank select code:
| Code: |
.................... #asm ASIS
.................... MOVF EECON1,W
000C: MOVF 0C,W
.................... MOVF EEDATA,W
000D: MOVF 0C,W
.................... MOVF TXSTA,W
000E: MOVF 18,W
.................... MOVF RCREG,W
000F: MOVF 1A,W
.................... #endasm |
With ASIS commented out, the compiler puts in bank select code:
| Code: |
.................... #asm // ASIS
.................... MOVF EECON1,W
000C: BSF 03.6
000D: MOVF 0C,W
.................... MOVF EEDATA,W
000E: BCF 03.5
000F: MOVF 0C,W
.................... MOVF TXSTA,W
0010: BSF 03.5
0011: BCF 03.6
0012: MOVF 18,W
.................... MOVF RCREG,W
0013: BCF 03.5
0014: MOVF 1A,W
.................... #endasm |
Here's the test program:
| Code: |
#include <16F877.H>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=4000000)
#byte RCREG = 0x1A
#byte TXSTA = 0x98
#byte EEDATA = 0x10C
#byte EECON1 = 0x18C
//============================
void main()
{
#asm // ASIS
MOVF EECON1,W
MOVF EEDATA,W
MOVF TXSTA,W
MOVF RCREG,W
#endasm
while(1);
} |
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joshkeys
Joined: 16 Aug 2005
Posts: 37
Location: Fredericton,NB
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| Posted: Thu Dec 14, 2006 4:48 pm |
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As usual, thanks PCM Programmer. Worked 100%. Now no more unexpected timing issues! Thanks!
Josh |
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drh
Joined: 12 Jul 2004
Posts: 192
Location: Hemet, California USA
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| Posted: Fri Dec 15, 2006 9:05 am |
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| joshkeys wrote: | As usual, thanks PCM Programmer. Worked 100%. Now no more unexpected timing issues! Thanks!
Josh |
Did you read all of my reply?
_________________
David |
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joshkeys
Joined: 16 Aug 2005
Posts: 37
Location: Fredericton,NB
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| Sorry |
| Posted: Fri Dec 15, 2006 2:49 pm |
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drh, i apologize, I guess I did not read the whole thing, well i am sure i did, but i guess as soon as i read the #asm and #endasm In my mind I had already formed an answer..  .. I apologize, I am not usually so quick to read something, I was in a rush at that time. My bad.. Thanks for the tip 
Josh |
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