X-Reportbug-Version: 3.18
X-Debbugs-Cc: [EMAIL PROTECTED]
Package: gcc-avr
Version: 1:4.1.0-1
Severity: important
This piece of code gets compiled incorrectly.
SIGNAL(SIG_INTERRUPT0)
{
if (PIND & _BV(PD2))
{
low_period=TCNT1;
}
else
{
high_period=TCNT1;
}
}
The Makefile looks like:
MCU:=atmega168
CC:=avr-gcc
OBJCOPY:=avr-objcopy
CFLAGS:=-g -mmcu=$(MCU) -Wall -Wstrict-prototypes -Os -mcall-prologues
-I/usr/avr/include -funroll-loops
LDFLAGS:=-g -lc
all: $(TARGET)
%.hex: %.out
$(OBJCOPY) -R .eeprom -O ihex $< $@
%.out: %.o
$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< -Wl,-Map,$(basename $<).map
%.s: %.c
$(CC) $(CFLAGS) -Os -S $<
%.o: %.s
$(CC) $(CFLAGS) -Os -c $<
The result is:
SIGNAL(SIG_INTERRUPT0)
{
294: 1f 92 push r1
296: 0f 92 push r0
298: 0f b6 in r0, 0x3f ; 63
29a: 0f 92 push r0
29c: 11 24 eor r1, r1
29e: 2f 93 push r18
2a0: 8f 93 push r24
2a2: 9f 93 push r25
if (PIND & _BV(PD2))
2a4: 4a 9b sbis 0x09, 2 ; 9
2a6: 09 c0 rjmp .+18 ; 0x2ba <__vector_1+0x26>
{
// now H
high_period=TCNT1;
2a8: 80 91 84 00 lds r24, 0x0084
2ac: 90 91 85 00 lds r25, 0x0085
2b0: 90 93 0c 01 sts 0x010C, r25
2b4: 80 93 0b 01 sts 0x010B, r24
2b8: 08 c0 rjmp .+16 ; 0x2ca <__vector_1+0x36>
}
else
{
low_period=TCNT1;
2ba: 20 91 84 00 lds r18, 0x0084
2be: 30 91 85 00 lds r19, 0x0085
2c2: 30 93 0e 01 sts 0x010E, r19
2c6: 20 93 0d 01 sts 0x010D, r18
2ca: 9f 91 pop r25
2cc: 8f 91 pop r24
2ce: 2f 91 pop r18
2d0: 0f 90 pop r0
2d2: 0f be out 0x3f, r0 ; 63
2d4: 0f 90 pop r0
2d6: 1f 90 pop r1
2d8: 18 95 reti
- r0, r1 are pushed/popped, r1 is zeroed.
If 0x3f really needs to be saved, it could be done by
another register, which has to be used anyway.
(or instead of (r18, r19, r24, r25) (r0,r1) should be used.)
- r19 is modified, but not saved
- this whole construct could be optimized very much better.
- -Os, as already used, is much better than without. -O7 or -O2
give the same result as -Os.
-- System Information:
Debian Release: testing/unstable
APT prefers testing
APT policy: (850, 'testing'), (600, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/dash
Kernel: Linux 2.6.15-1-k7
Locale: LANG=de_AT, LC_CTYPE=de_AT (charmap=ISO-8859-1)
Versions of packages gcc-avr depends on:
ii binutils-avr 2.16.1-1 Binary utilities that support Atme
ii libc6 2.3.6-7 GNU C Library: Shared libraries
gcc-avr recommends no packages.
-- no debconf information
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