求教winavr编程时for循环的问题！！

olony

初学winavr自己编了个小测试程序内容如下：（使用WinAVR-20080610编程软件 mmcu=atmega169pv  主频 7.3728MHz ）
结果发现好像其中一个的for循环没有执行！！示波器显示的矩形波高低电平不等宽！
请高手指点问题所在！！

//测试程序如下：
#include <avr/io.h>
#include <stdint.h>
int main(void)
{
uint8_t i;
DDRB|=(1<<PB7);
while(1)
{
    for(i=1;i<200;i++) ;       
    PORTB&=~(1<<PB7);
    for(i=1;i<200;i++) ;       
    PORTB|=(1<<PB7);  
  }
}

//--------------------------------------//
//makefile 使用winavr 自带工具生成如下：//
//--------------------------------------//

# Hey Emacs, this is a -*- makefile -*-
#----------------------------------------------------------------------------
# WinAVR Makefile Template written by Eric B. Weddington, J顤g Wunsch, et al.
#
# Released to the Public Domain
#
# Additional material for this makefile was written by:
# Peter Fleury
# Tim Henigan
# Colin O'Flynn
# Reiner Patommel
# Markus Pfaff
# Sander Pool
# Frederik Rouleau
# Carlos Lamas
#
#----------------------------------------------------------------------------
# On command line:
#
# make all = Make software.
#
# make clean = Clean out built project files.
#
# make coff = Convert ELF to AVR COFF.
#
# make extcoff = Convert ELF to AVR Extended COFF.
#
# make program = Download the hex file to the device, using avrdude.
#                Please customize the avrdude settings below first!
#
# make debug = Start either simulavr or avarice as specified for debugging,
#              with avr-gdb or avr-insight as the front end for debugging.
#
# make filename.s = Just compile filename.c into the assembler code only.
#
# make filename.i = Create a preprocessed source file for use in submitting
#                   bug reports to the GCC project.
#
# To rebuild project do "make clean" then "make all".
#----------------------------------------------------------------------------


# MCU name
MCU = atmega169p


# Processor frequency.
#     This will define a symbol, F_CPU, in all source code files equal to the
#     processor frequency. You can then use this symbol in your source code to
#     calculate timings. Do NOT tack on a 'UL' at the end, this will be done
#     automatically to create a 32-bit value in your source code.
#     Typical values are:
#         F_CPU =  1000000
#         F_CPU =  1843200
#         F_CPU =  2000000
#         F_CPU =  3686400
#         F_CPU =  4000000
#         F_CPU =  7372800
#         F_CPU =  8000000
#         F_CPU = 11059200
#         F_CPU = 14745600
#         F_CPU = 16000000
#         F_CPU = 18432000
#         F_CPU = 20000000
F_CPU = 7372800


# Output format. (can be srec, ihex, binary)
FORMAT = ihex


# Target file name (without extension).
TARGET = for


# Object files directory
#     To put object files in current directory, use a dot (.), do NOT make
#     this an empty or blank macro!
OBJDIR = .


# List C source files here. (C dependencies are automatically generated.)
SRC = $(TARGET).c


# List C++ source files here. (C dependencies are automatically generated.)
CPPSRC =


# List Assembler source files here.
#     Make them always end in a capital .S.  Files ending in a lowercase .s
#     will not be considered source files but generated files (assembler
#     output from the compiler), and will be deleted upon "make clean"!
#     Even though the DOS/Win* filesystem matches both .s and .S the same,
#     it will preserve the spelling of the filenames, and gcc itself does
#     care about how the name is spelled on its command-line.
ASRC =


# Optimization level, can be [0, 1, 2, 3, s].
#     0 = turn off optimization. s = optimize for size.
#     (Note: 3 is not always the best optimization level. See avr-libc FAQ.)
OPT = s


# Debugging format.
#     Native formats for AVR-GCC's -g are dwarf-2 [default] or stabs.
#     AVR Studio 4.10 requires dwarf-2.
#     AVR [Extended] COFF format requires stabs, plus an avr-objcopy run.
DEBUG = dwarf-2


# List any extra directories to look for include files here.
#     Each directory must be seperated by a space.
#     Use forward slashes for directory separators.
#     For a directory that has spaces, enclose it in quotes.
EXTRAINCDIRS =


# Compiler flag to set the C Standard level.
#     c89   = "ANSI" C
#     gnu89 = c89 plus GCC extensions
#     c99   = ISO C99 standard (not yet fully implemented)
#     gnu99 = c99 plus GCC extensions
CSTANDARD = -std=gnu99


# Place -D or -U options here for C sources
CDEFS = -DF_CPU=$(F_CPU)UL


# Place -D or -U options here for ASM sources
ADEFS = -DF_CPU=$(F_CPU)


# Place -D or -U options here for C++ sources
CPPDEFS = -DF_CPU=$(F_CPU)UL
#CPPDEFS += -D__STDC_LIMIT_MACROS
#CPPDEFS += -D__STDC_CONSTANT_MACROS



#---------------- Compiler Options C ----------------
#  -g*:          generate debugging information
#  -O*:          optimization level
#  -f...:        tuning, see GCC manual and avr-libc documentation
#  -Wall...:     warning level
#  -Wa,...:      tell GCC to pass this to the assembler.
#    -adhlns...: create assembler listing
CFLAGS = -g$(DEBUG)
CFLAGS += $(CDEFS)
CFLAGS += -O$(OPT)
CFLAGS += -funsigned-char
CFLAGS += -funsigned-bitfields
CFLAGS += -fpack-struct
CFLAGS += -fshort-enums
CFLAGS += -Wall
CFLAGS += -Wstrict-prototypes
#CFLAGS += -mshort-calls
#CFLAGS += -fno-unit-at-a-time
#CFLAGS += -Wundef
#CFLAGS += -Wunreachable-code
#CFLAGS += -Wsign-compare
CFLAGS += -Wa,-adhlns=$(<:%.c=$(OBJDIR)/%.lst)
CFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
CFLAGS += $(CSTANDARD)


#---------------- Compiler Options C++ ----------------
#  -g*:          generate debugging information
#  -O*:          optimization level
#  -f...:        tuning, see GCC manual and avr-libc documentation
#  -Wall...:     warning level
#  -Wa,...:      tell GCC to pass this to the assembler.
#    -adhlns...: create assembler listing
CPPFLAGS = -g$(DEBUG)
CPPFLAGS += $(CPPDEFS)
CPPFLAGS += -O$(OPT)
CPPFLAGS += -funsigned-char
CPPFLAGS += -funsigned-bitfields
CPPFLAGS += -fpack-struct
CPPFLAGS += -fshort-enums
CPPFLAGS += -fno-exceptions
CPPFLAGS += -Wall
CFLAGS += -Wundef
#CPPFLAGS += -mshort-calls
#CPPFLAGS += -fno-unit-at-a-time
#CPPFLAGS += -Wstrict-prototypes
#CPPFLAGS += -Wunreachable-code
#CPPFLAGS += -Wsign-compare
CPPFLAGS += -Wa,-adhlns=$(<:%.cpp=$(OBJDIR)/%.lst)
CPPFLAGS += $(patsubst %,-I%,$(EXTRAINCDIRS))
#CPPFLAGS += $(CSTANDARD)


#---------------- Assembler Options ----------------
#  -Wa,...:   tell GCC to pass this to the assembler.
#  -adhlns:   create listing
#  -gstabs:   have the assembler create line number information; note that
#             for use in COFF files, additional information about filenames
#             and function names needs to be present in the assembler source
#             files -- see avr-libc docs [FIXME: not yet described there]
#  -listing-cont-lines: Sets the maximum number of continuation lines of hex
#       dump that will be displayed for a given single line of source input.
ASFLAGS = $(ADEFS) -Wa,-adhlns=$(<:%.S=$(OBJDIR)/%.lst),-gstabs,--listing-cont-lines=100


#---------------- Library Options ----------------
# Minimalistic printf version
PRINTF_LIB_MIN = -Wl,-u,vfprintf -lprintf_min

# Floating point printf version (requires MATH_LIB = -lm below)
PRINTF_LIB_FLOAT = -Wl,-u,vfprintf -lprintf_flt

# If this is left blank, then it will use the Standard printf version.
PRINTF_LIB =
#PRINTF_LIB = $(PRINTF_LIB_MIN)
#PRINTF_LIB = $(PRINTF_LIB_FLOAT)


# Minimalistic scanf version
SCANF_LIB_MIN = -Wl,-u,vfscanf -lscanf_min

# Floating point + %[ scanf version (requires MATH_LIB = -lm below)
SCANF_LIB_FLOAT = -Wl,-u,vfscanf -lscanf_flt

# If this is left blank, then it will use the Standard scanf version.
SCANF_LIB =
#SCANF_LIB = $(SCANF_LIB_MIN)
#SCANF_LIB = $(SCANF_LIB_FLOAT)


MATH_LIB = -lm


# List any extra directories to look for libraries here.
#     Each directory must be seperated by a space.
#     Use forward slashes for directory separators.
#     For a directory that has spaces, enclose it in quotes.
EXTRALIBDIRS =



#---------------- External Memory Options ----------------

# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# used for variables (.data/.bss) and heap (malloc()).
#EXTMEMOPTS = -Wl,-Tdata=0x801100,--defsym=__heap_end=0x80ffff

# 64 KB of external RAM, starting after internal RAM (ATmega128!),
# only used for heap (malloc()).
#EXTMEMOPTS = -Wl,--section-start,.data=0x801100,--defsym=__heap_end=0x80ffff

EXTMEMOPTS =



#---------------- Linker Options ----------------
#  -Wl,...:     tell GCC to pass this to linker.
#    -Map:      create map file
#    --cref:    add cross reference to  map file
LDFLAGS = -Wl,-Map=$(TARGET).map,--cref
LDFLAGS += $(EXTMEMOPTS)
LDFLAGS += $(patsubst %,-L%,$(EXTRALIBDIRS))
LDFLAGS += $(PRINTF_LIB) $(SCANF_LIB) $(MATH_LIB)
#LDFLAGS += -T linker_script.x



#---------------- Programming Options (avrdude) ----------------

# Programming hardware
# Type: avrdude -c ?
# to get a full listing.
#
AVRDUDE_PROGRAMMER = stk500v2

# com1 = serial port. Use lpt1 to connect to parallel port.
AVRDUDE_PORT = com1    # programmer connected to serial device

AVRDUDE_WRITE_FLASH = -U flash:w:$(TARGET).hex
#AVRDUDE_WRITE_EEPROM = -U eeprom:w:$(TARGET).eep


# Uncomment the following if you want avrdude's erase cycle counter.
# Note that this counter needs to be initialized first using -Yn,
# see avrdude manual.
#AVRDUDE_ERASE_COUNTER = -y

# Uncomment the following if you do /not/ wish a verification to be
# performed after programming the device.
#AVRDUDE_NO_VERIFY = -V

# Increase verbosity level.  Please use this when submitting bug
# reports about avrdude. See <http://savannah.nongnu.org/projects/avrdude>
# to submit bug reports.
#AVRDUDE_VERBOSE = -v -v

AVRDUDE_FLAGS = -p $(MCU) -P $(AVRDUDE_PORT) -c $(AVRDUDE_PROGRAMMER)
AVRDUDE_FLAGS += $(AVRDUDE_NO_VERIFY)
AVRDUDE_FLAGS += $(AVRDUDE_VERBOSE)
AVRDUDE_FLAGS += $(AVRDUDE_ERASE_COUNTER)



#---------------- Debugging Options ----------------

# For simulavr only - target MCU frequency.
DEBUG_MFREQ = $(F_CPU)

# Set the DEBUG_UI to either gdb or insight.
# DEBUG_UI = gdb
DEBUG_UI = insight

# Set the debugging back-end to either avarice, simulavr.
DEBUG_BACKEND = avarice
#DEBUG_BACKEND = simulavr

# GDB Init Filename.
GDBINIT_FILE = __avr_gdbinit

# When using avarice settings for the JTAG
JTAG_DEV = /dev/com1

# Debugging port used to communicate between GDB / avarice / simulavr.
DEBUG_PORT = 4242

# Debugging host used to communicate between GDB / avarice / simulavr, normally
#     just set to localhost unless doing some sort of crazy debugging when
#     avarice is running on a different computer.
DEBUG_HOST = localhost



#============================================================================


# Define programs and commands.
SHELL = sh
CC = avr-gcc
OBJCOPY = avr-objcopy
OBJDUMP = avr-objdump
SIZE = avr-size
AR = avr-ar rcs
NM = avr-nm
AVRDUDE = avrdude
REMOVE = rm -f
REMOVEDIR = rm -rf
COPY = cp
WINSHELL = cmd


# Define Messages
# English
MSG_ERRORS_NONE = Errors: none
MSG_BEGIN = -------- begin --------
MSG_END = --------  end  --------
MSG_SIZE_BEFORE = Size before:
MSG_SIZE_AFTER = Size after:
MSG_COFF = Converting to AVR COFF:
MSG_EXTENDED_COFF = Converting to AVR Extended COFF:
MSG_FLASH = Creating load file for Flash:
MSG_EEPROM = Creating load file for EEPROM:
MSG_EXTENDED_LISTING = Creating Extended Listing:
MSG_SYMBOL_TABLE = Creating Symbol Table:
MSG_LINKING = Linking:
MSG_COMPILING = Compiling C:
MSG_COMPILING_CPP = Compiling C++:
MSG_ASSEMBLING = Assembling:
MSG_CLEANING = Cleaning project:
MSG_CREATING_LIBRARY = Creating library:




# Define all object files.
OBJ = $(SRC:%.c=$(OBJDIR)/%.o) $(CPPSRC:%.cpp=$(OBJDIR)/%.o) $(ASRC:%.S=$(OBJDIR)/%.o)

# Define all listing files.
LST = $(SRC:%.c=$(OBJDIR)/%.lst) $(CPPSRC:%.cpp=$(OBJDIR)/%.lst) $(ASRC:%.S=$(OBJDIR)/%.lst)


# Compiler flags to generate dependency files.
GENDEPFLAGS = -MMD -MP -MF .dep/$(@F).d


# Combine all necessary flags and optional flags.
# Add target processor to flags.
ALL_CFLAGS = -mmcu=$(MCU) -I. $(CFLAGS) $(GENDEPFLAGS)
ALL_CPPFLAGS = -mmcu=$(MCU) -I. -x c++ $(CPPFLAGS) $(GENDEPFLAGS)
ALL_ASFLAGS = -mmcu=$(MCU) -I. -x assembler-with-cpp $(ASFLAGS)





# Default target.
all: begin gccversion sizebefore build sizeafter end

# Change the build target to build a HEX file or a library.
build: elf hex eep lss sym
#build: lib


elf: $(TARGET).elf
hex: $(TARGET).hex
eep: $(TARGET).eep
lss: $(TARGET).lss
sym: $(TARGET).sym
LIBNAME=lib$(TARGET).a
lib: $(LIBNAME)



# Eye candy.
# AVR Studio 3.x does not check make's exit code but relies on
# the following magic strings to be generated by the compile job.
begin:
        @echo
        @echo $(MSG_BEGIN)

end:
        @echo $(MSG_END)
        @echo


# Display size of file.
HEXSIZE = $(SIZE) --target=$(FORMAT) $(TARGET).hex
ELFSIZE = $(SIZE) --mcu=$(MCU) --format=avr $(TARGET).elf

sizebefore:
        @if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_BEFORE); $(ELFSIZE); \
        2>/dev/null; echo; fi

sizeafter:
        @if test -f $(TARGET).elf; then echo; echo $(MSG_SIZE_AFTER); $(ELFSIZE); \
        2>/dev/null; echo; fi



# Display compiler version information.
gccversion :
        @$(CC) --version



# Program the device.  
program: $(TARGET).hex $(TARGET).eep
        $(AVRDUDE) $(AVRDUDE_FLAGS) $(AVRDUDE_WRITE_FLASH) $(AVRDUDE_WRITE_EEPROM)


# Generate avr-gdb config/init file which does the following:
#     define the reset signal, load the target file, connect to target, and set
#     a breakpoint at main().
gdb-config:
        @$(REMOVE) $(GDBINIT_FILE)
        @echo define reset >> $(GDBINIT_FILE)
        @echo SIGNAL SIGHUP >> $(GDBINIT_FILE)
        @echo end >> $(GDBINIT_FILE)
        @echo file $(TARGET).elf >> $(GDBINIT_FILE)
        @echo target remote $(DEBUG_HOST):$(DEBUG_PORT)  >> $(GDBINIT_FILE)
ifeq ($(DEBUG_BACKEND),simulavr)
        @echo load  >> $(GDBINIT_FILE)
endif
        @echo break main >> $(GDBINIT_FILE)

debug: gdb-config $(TARGET).elf
ifeq ($(DEBUG_BACKEND), avarice)
        @echo Starting AVaRICE - Press enter when "waiting to connect" message displays.
        @$(WINSHELL) /c start avarice --jtag $(JTAG_DEV) --erase --program --file \
        $(TARGET).elf $(DEBUG_HOST):$(DEBUG_PORT)
        @$(WINSHELL) /c pause

else
        @$(WINSHELL) /c start simulavr --gdbserver --device $(MCU) --clock-freq \
        $(DEBUG_MFREQ) --port $(DEBUG_PORT)
endif
        @$(WINSHELL) /c start avr-$(DEBUG_UI) --command=$(GDBINIT_FILE)




# Convert ELF to COFF for use in debugging / simulating in AVR Studio or VMLAB.
COFFCONVERT = $(OBJCOPY) --debugging
COFFCONVERT += --change-section-address .data-0x800000
COFFCONVERT += --change-section-address .bss-0x800000
COFFCONVERT += --change-section-address .noinit-0x800000
COFFCONVERT += --change-section-address .eeprom-0x810000



coff: $(TARGET).elf
        @echo
        @echo $(MSG_COFF) $(TARGET).cof
        $(COFFCONVERT) -O coff-avr $< $(TARGET).cof


extcoff: $(TARGET).elf
        @echo
        @echo $(MSG_EXTENDED_COFF) $(TARGET).cof
        $(COFFCONVERT) -O coff-ext-avr $< $(TARGET).cof



# Create final output files (.hex, .eep) from ELF output file.
%.hex: %.elf
        @echo
        @echo $(MSG_FLASH) $@
        $(OBJCOPY) -O $(FORMAT) -R .eeprom -R .fuse -R .lock $< $@

%.eep: %.elf
        @echo
        @echo $(MSG_EEPROM) $@
        -$(OBJCOPY) -j .eeprom --set-section-flags=.eeprom="alloc,load" \
        --change-section-lma .eeprom=0 --no-change-warnings -O $(FORMAT) $< $@ || exit 0

# Create extended listing file from ELF output file.
%.lss: %.elf
        @echo
        @echo $(MSG_EXTENDED_LISTING) $@
        $(OBJDUMP) -h -S -z $< > $@

# Create a symbol table from ELF output file.
%.sym: %.elf
        @echo
        @echo $(MSG_SYMBOL_TABLE) $@
        $(NM) -n $< > $@



# Create library from object files.
.SECONDARY : $(TARGET).a
.PRECIOUS : $(OBJ)
%.a: $(OBJ)
        @echo
        @echo $(MSG_CREATING_LIBRARY) $@
        $(AR) $@ $(OBJ)


# Link: create ELF output file from object files.
.SECONDARY : $(TARGET).elf
.PRECIOUS : $(OBJ)
%.elf: $(OBJ)
        @echo
        @echo $(MSG_LINKING) $@
        $(CC) $(ALL_CFLAGS) $^ --output $@ $(LDFLAGS)


# Compile: create object files from C source files.
$(OBJDIR)/%.o : %.c
        @echo
        @echo $(MSG_COMPILING) $<
        $(CC) -c $(ALL_CFLAGS) $< -o $@


# Compile: create object files from C++ source files.
$(OBJDIR)/%.o : %.cpp
        @echo
        @echo $(MSG_COMPILING_CPP) $<
        $(CC) -c $(ALL_CPPFLAGS) $< -o $@


# Compile: create assembler files from C source files.
%.s : %.c
        $(CC) -S $(ALL_CFLAGS) $< -o $@


# Compile: create assembler files from C++ source files.
%.s : %.cpp
        $(CC) -S $(ALL_CPPFLAGS) $< -o $@


# Assemble: create object files from assembler source files.
$(OBJDIR)/%.o : %.S
        @echo
        @echo $(MSG_ASSEMBLING) $<
        $(CC) -c $(ALL_ASFLAGS) $< -o $@


# Create preprocessed source for use in sending a bug report.
%.i : %.c
        $(CC) -E -mmcu=$(MCU) -I. $(CFLAGS) $< -o $@


# Target: clean project.
clean: begin clean_list end

clean_list :
        @echo
        @echo $(MSG_CLEANING)
        $(REMOVE) $(TARGET).hex
        $(REMOVE) $(TARGET).eep
        $(REMOVE) $(TARGET).cof
        $(REMOVE) $(TARGET).elf
        $(REMOVE) $(TARGET).map
        $(REMOVE) $(TARGET).sym
        $(REMOVE) $(TARGET).lss
        $(REMOVE) $(SRC:%.c=$(OBJDIR)/%.o)
        $(REMOVE) $(SRC:%.c=$(OBJDIR)/%.lst)
        $(REMOVE) $(SRC:.c=.s)
        $(REMOVE) $(SRC:.c=.d)
        $(REMOVE) $(SRC:.c=.i)
        $(REMOVEDIR) .dep


# Create object files directory
$(shell mkdir $(OBJDIR) 2>/dev/null)


# Include the dependency files.
-include $(shell mkdir .dep 2>/dev/null) $(wildcard .dep/*)


# Listing of phony targets.
.PHONY : all begin finish end sizebefore sizeafter gccversion \
build elf hex eep lss sym coff extcoff \
clean clean_list program debug gdb-config

//--------------------//
//makeall 以后输出如下//
//--------------------//

> "make.exe" all

-------- begin --------
avr-gcc (WinAVR 20080610) 4.3.0
Copyright (C) 2008 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


Compiling C: for.c
avr-gcc -c -mmcu=atmega169p -I. -gdwarf-2 -DF_CPU=7372800UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Wstrict-prototypes -Wa,-adhlns=./for.lst  -std=gnu99 -Wundef -MMD -MP -MF .dep/for.o.d for.c -o for.o

Linking: for.elf
avr-gcc -mmcu=atmega169p -I. -gdwarf-2 -DF_CPU=7372800UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Wstrict-prototypes -Wa,-adhlns=for.o  -std=gnu99 -Wundef -MMD -MP -MF .dep/for.elf.d for.o --output for.elf -Wl,-Map=for.map,--cref     -lm

Creating load file for Flash: for.hex
avr-objcopy -O ihex -R .eeprom -R .fuse -R .lock for.elf for.hex

Creating load file for EEPROM: for.eep
avr-objcopy -j .eeprom --set-section-flags=.eeprom="alloc,load" \
        --change-section-lma .eeprom=0 --no-change-warnings -O ihex for.elf for.eep || exit 0

Creating Extended Listing: for.lss
avr-objdump -h -S -z for.elf > for.lss

Creating Symbol Table: for.sym
avr-nm -n for.elf > for.sym

Size after:
AVR Memory Usage
----------------
Device: atmega169p

Program:     178 bytes (1.1% Full)
(.text + .data + .bootloader)

Data:          0 bytes (0.0% Full)
(.data + .bss + .noinit)

//----------------//
//生成的.s程序如下//
//----------------//

.file        "for.c"
__SREG__ = 0x3f
__SP_H__ = 0x3e
__SP_L__ = 0x3d
__CCP__  = 0x34
__tmp_reg__ = 0
__zero_reg__ = 1
        .global __do_copy_data
        .global __do_clear_bss
        .section        .debug_abbrev,"",@progbits
.Ldebug_abbrev0:
        .section        .debug_info,"",@progbits
.Ldebug_info0:
        .section        .debug_line,"",@progbits
.Ldebug_line0:
        .text
.Ltext0:
.global        main
        .type        main, @function
main:
.LFB2:
.LM1:
/* prologue: function */
/* frame size = 0 */
.LM2:
        sbi 36-32,7
        ldi r24,lo8(1)
.LVL0:
        rjmp .L5
.L3:
.LM3:
        subi r24,lo8(-(1))
.L5:
        cpi r24,lo8(-56)
        brlo .L3
.LM4:
        cbi 37-32,7
.LM5:
        sbi 37-32,7
        ldi r24,lo8(1)
        rjmp .L3
.LFE2:
        .size        main, .-main
        .section        .debug_frame,"",@progbits
.Lframe0:
        .long        .LECIE0-.LSCIE0
.LSCIE0:
        .long        0xffffffff
        .byte        0x1
        .string        ""
        .uleb128 0x1
        .sleb128 -1
        .byte        0x24
        .byte        0xc
        .uleb128 0x20
        .uleb128 0x0
        .p2align        2
.LECIE0:
.LSFDE0:
        .long        .LEFDE0-.LASFDE0
.LASFDE0:
        .long        .Lframe0
        .long        .LFB2
        .long        .LFE2-.LFB2
        .p2align        2
.LEFDE0:
        .text
.Letext0:
        .section        .debug_info
        .long        0x89
        .word        0x2
        .long        .Ldebug_abbrev0
        .byte        0x4
        .uleb128 0x1
        .long        .LASF7
        .byte        0x1
        .long        .LASF8
        .long        .LASF9
        .long        .Ltext0
        .long        .Letext0
        .long        .Ldebug_line0
        .uleb128 0x2
        .byte        0x1
        .byte        0x6
        .long        .LASF0
        .uleb128 0x3
        .long        .LASF10
        .byte        0x2
        .byte        0x7a
        .long        0x37
        .uleb128 0x2
        .byte        0x1
        .byte        0x8
        .long        .LASF1
        .uleb128 0x4
        .byte        0x2
        .byte        0x5
        .string        "int"
        .uleb128 0x2
        .byte        0x2
        .byte        0x7
        .long        .LASF2
        .uleb128 0x2
        .byte        0x4
        .byte        0x5
        .long        .LASF3
        .uleb128 0x2
        .byte        0x4
        .byte        0x7
        .long        .LASF4
        .uleb128 0x2
        .byte        0x8
        .byte        0x5
        .long        .LASF5
        .uleb128 0x2
        .byte        0x8
        .byte        0x7
        .long        .LASF6
        .uleb128 0x5
        .byte        0x1
        .long        .LASF11
        .byte        0x1
        .byte        0x4
        .byte        0x1
        .long        0x3e
        .long        .LFB2
        .long        .LFE2
        .byte        0x2
        .byte        0x90
        .uleb128 0x20
        .uleb128 0x6
        .string        "i"
        .byte        0x1
        .byte        0x5
        .long        0x2c
        .byte        0x1
        .byte        0x68
        .byte        0x0
        .byte        0x0
        .section        .debug_abbrev
        .uleb128 0x1
        .uleb128 0x11
        .byte        0x1
        .uleb128 0x25
        .uleb128 0xe
        .uleb128 0x13
        .uleb128 0xb
        .uleb128 0x3
        .uleb128 0xe
        .uleb128 0x1b
        .uleb128 0xe
        .uleb128 0x11
        .uleb128 0x1
        .uleb128 0x12
        .uleb128 0x1
        .uleb128 0x10
        .uleb128 0x6
        .byte        0x0
        .byte        0x0
        .uleb128 0x2
        .uleb128 0x24
        .byte        0x0
        .uleb128 0xb
        .uleb128 0xb
        .uleb128 0x3e
        .uleb128 0xb
        .uleb128 0x3
        .uleb128 0xe
        .byte        0x0
        .byte        0x0
        .uleb128 0x3
        .uleb128 0x16
        .byte        0x0
        .uleb128 0x3
        .uleb128 0xe
        .uleb128 0x3a
        .uleb128 0xb
        .uleb128 0x3b
        .uleb128 0xb
        .uleb128 0x49
        .uleb128 0x13
        .byte        0x0
        .byte        0x0
        .uleb128 0x4
        .uleb128 0x24
        .byte        0x0
        .uleb128 0xb
        .uleb128 0xb
        .uleb128 0x3e
        .uleb128 0xb
        .uleb128 0x3
        .uleb128 0x8
        .byte        0x0
        .byte        0x0
        .uleb128 0x5
        .uleb128 0x2e
        .byte        0x1
        .uleb128 0x3f
        .uleb128 0xc
        .uleb128 0x3
        .uleb128 0xe
        .uleb128 0x3a
        .uleb128 0xb
        .uleb128 0x3b
        .uleb128 0xb
        .uleb128 0x27
        .uleb128 0xc
        .uleb128 0x49
        .uleb128 0x13
        .uleb128 0x11
        .uleb128 0x1
        .uleb128 0x12
        .uleb128 0x1
        .uleb128 0x40
        .uleb128 0xa
        .byte        0x0
        .byte        0x0
        .uleb128 0x6
        .uleb128 0x34
        .byte        0x0
        .uleb128 0x3
        .uleb128 0x8
        .uleb128 0x3a
        .uleb128 0xb
        .uleb128 0x3b
        .uleb128 0xb
        .uleb128 0x49
        .uleb128 0x13
        .uleb128 0x2
        .uleb128 0xa
        .byte        0x0
        .byte        0x0
        .byte        0x0
        .section        .debug_pubnames,"",@progbits
        .long        0x17
        .word        0x2
        .long        .Ldebug_info0
        .long        0x8d
        .long        0x68
        .string        "main"
        .long        0x0
        .section        .debug_aranges,"",@progbits
        .long        0x1c
        .word        0x2
        .long        .Ldebug_info0
        .byte        0x4
        .byte        0x0
        .word        0x0
        .word        0x0
        .long        .Ltext0
        .long        .Letext0-.Ltext0
        .long        0x0
        .long        0x0
        .section        .debug_line
        .long        .LELT0-.LSLT0
.LSLT0:
        .word        0x2
        .long        .LELTP0-.LASLTP0
.LASLTP0:
        .byte        0x1
        .byte        0x1
        .byte        0xf6
        .byte        0xf5
        .byte        0xa
        .byte        0x0
        .byte        0x1
        .byte        0x1
        .byte        0x1
        .byte        0x1
        .byte        0x0
        .byte        0x0
        .byte        0x0
        .byte        0x1
        .ascii        "d:/winavr~1/lib/gcc/../../avr/include"
        .byte        0
        .byte        0x0
        .string        "for.c"
        .uleb128 0x0
        .uleb128 0x0
        .uleb128 0x0
        .string        "stdint.h"
        .uleb128 0x1
        .uleb128 0x0
        .uleb128 0x0
        .byte        0x0
.LELTP0:
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .LM1
        .byte        0x17
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .LM2
        .byte        0x16
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .LM3
        .byte        0x17
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .LM4
        .byte        0x15
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .LM5
        .byte        0x16
        .byte        0x0
        .uleb128 0x5
        .byte        0x2
        .long        .Letext0
        .byte        0x0
        .uleb128 0x1
        .byte        0x1
.LELT0:
        .section        .debug_str,"MS",@progbits,1
.LASF7:
        .string        "GNU C 4.3.0"
.LASF2:
        .string        "unsigned int"
.LASF4:
        .string        "long unsigned int"
.LASF10:
        .string        "uint8_t"
.LASF0:
        .string        "signed char"
.LASF6:
        .string        "long long unsigned int"
.LASF1:
        .string        "unsigned char"
.LASF3:
        .string        "long int"
.LASF11:
        .string        "main"
.LASF8:
        .string        "for.c"
.LASF9:
        .string        "G:\\TEST_GCC\\LED\\ICCGCC\\GCC"
.LASF5:
        .string        "long long int"

olony

此问题已解决，是编译器优化级出的问题，改为0就好了，或将变量 i 声明为volatile int8_t i;就好了