AVR-Chat

Tim, this was also very helpful to me also.  Thanks.  Besides plain
variables, what do you do to pass C arrays and C structs?   Steve

 

From: AVR-Chat@yahoogroups.com [mailto:AVR-Chat@yahoogroups.com] On Behalf
Of Tim Mitchell
Sent: Tuesday, March 27, 2012 1:51 AM
To: AVR-Chat@yahoogroups.com
Subject: RE: [AVR-Chat] Re: Mixing C and assembly with special requirements.

 

  

I'm a bit of an assembly nut and have had good results mixing asm and c.
(But not reserving registers, that just ties the compiler in knots)

I create an asm.s file in the project and define any variables I need in one
of the c files. Then using .extern in the asm file you can use that
variable.

If it's not an assembly routine you pass parameters using register pairs,
there is a good AVRGCC help page listing which registers are used.

For example this is a timer interrupt handler for pulse width modulating an
RGBW LED in assembler






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