URL:
<http://savannah.nongnu.org/bugs/?31768>
Summary: Difference in address between using a direct var or
through a struct
Project: AVR C Runtime Library
Submitted by: lourens
Submitted on: Thu 25 Nov 2010 08:14:07 PM GMT
Category: Library
Severity: 3 - Normal
Priority: 5 - Normal
Item Group: None
Status: None
Percent Complete: 0%
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Release: 1.6.8
Fixed Release: None
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Details:
When I compile this code:
ADCA.CH0.MUXCTRL = ADC_CH_MUXPOS_PIN0_gc;
The assembler result is:
204: e0 e0 ldi r30, 0x00 ; 0
206: f2 e0 ldi r31, 0x02 ; 2
208: 13 8e std Z+27, r1 ; 0x1b
And with this code:
ADCA_CH0_MUXCTRL = ADC_CH_MUXPOS_PIN0_gc;
The result is:
204: e1 e2 ldi r30, 0x21 ; 33
206: f2 e0 ldi r31, 0x02 ; 2
208: 10 82 st Z, r1
Although I don't care about the difference in using st or std, the problem is
that the accessed addresses are different. The last one seems right as it
works while the first one isn't. I checked through the header files and
compared them with the datasheet. At first sight I don't see a problem there,
so maybe it is the compiler doing something incompatible?
My version of avr-libc is 1.6.8 and avr-gcc is 4.3.4.
The command was:
avr-gcc -mmcu=atxmega64d3 -Wall -W -Wcast-align -Wcast-qual -Wimplicit
-Wpointer-arith -Wswitch -Wredundant-decls -Wreturn-type -Wshadow -Wno-unused
-Wstrict-prototypes -Wnested-externs -g -I. -DCPU_FREQ=10000000UL
-DF_CPU=CPU_FREQ -c main.c -o obj/main.o
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