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| Search found 4 matches |
| Author | Message |
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 Topic: int1 = val&1 optimization possible? |
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| matt.dawson Replies: 8 Views: 10557 |
 Forum: General CCS C Discussion Posted: Fri Oct 31, 2014 2:55 am Subject: int1 = val&1 optimization possible? |
| In "a & 1", 1 is a constant.
Optimized paths don't have to handle everything, they are chosen based upon the specific code written. |
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| Topic: int1 = val&1 optimization possible? |
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| matt.dawson Replies: 8 Views: 10557 |
Forum: General CCS C Discussion Posted: Fri Oct 31, 2014 2:32 am Subject: int1 = val&1 optimization possible? |
| Yes I understand why it's done in the generic case.
The case I'm talking about is an optimization for when the last operation in an expression is a constant and of 1. It isn't hard to detect that in ... |
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| Topic: int1 = val&1 optimization possible? |
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| matt.dawson Replies: 8 Views: 10557 |
Forum: General CCS C Discussion Posted: Thu Oct 30, 2014 10:19 pm Subject: int1 = val&1 optimization possible? |
| That's exactly it.
I've tested this in PCM Compiler v5.030, compiling at optimisation level 9 and it generates the same extra bit clears, tests and sets. #include <16LF1705.h> void main ... |
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| Topic: int1 = val&1 optimization possible? |
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| matt.dawson Replies: 8 Views: 10557 |
Forum: General CCS C Discussion Posted: Thu Oct 30, 2014 8:14 pm Subject: int1 = val&1 optimization possible? |
| I notice in my code that this compiles to:
.................... int1 b = (crc & 1); 17E4: MOVF 27,W 17E5: ANDLW 01 17E6: MOVWF 77 17E7: CLRF 7A 17E8: BCF 29.0 17E9 ... |
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