Optimizing CCS output to produce MSP430 Instructions Bit-Set and Bit-Clear.....

EmbeddedGuy

Hello,

I am using CCSv4 with the MSP4302618. I have noticed that the compiler does not always produce assembly language output using the MSP430 instructions "bic.b" and "bis.b" when using statements like "P5OUT &= 0xF7;".

My question is.....What level of optimization is needed to coerce the CCSv4 compiler to always produce the corresponding bit-set and bit-clr instructions.

I am familiar with the the compiler intrinsic functions listed in in430.h.

Perhaps it is possible to use the ASM statement (listed in slau132e.pdf). I have not had much luck in creating a general purpose macro.

I would appreciate any thoughts on the best way to change CCSv4 optimization or to use the ASM statement to provide a general purpose macro.

Thanks in advance for your assistance.

....EmbeddedGuy

over 14 years ago

0 Paul Knueven over 14 years ago

TI__Expert 4280 points

This may not give you all you are looking for, but forum entry http://e2e.ti.com/support/development_tools/compiler/f/343/t/151189.aspx addresses the topic.

0 EmbeddedGuy over 14 years ago in reply to Paul Knueven

Intellectual 410 points

Thank you for the reference. I will take a look at it.

....EmbeddedGuy

0 EmbeddedGuy over 13 years ago in reply to EmbeddedGuy

Intellectual 410 points

Hi Georgem,

your reference was helpful but did not really resolve the issue for me as I do not believe that TI has properly described the problem. I was aware that the "C" OR instruction did compile to a BSET opcode but that the "C" AND instruction did not compile to a BCLR opcode. Perhaps knowing this bit of info is sufficient to carry on.

Thanks again for your response. You may consider this issue resolved!

....EmbeddedGuy

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Optimizing CCS output to produce MSP430 Instructions Bit-Set and Bit-Clear.....