CFLAGS += -ffunction-sections

LDFLAGS += -Wl,--gc-sections
LDFLAGS += -Wl,--relax

D:\Projects_UPD\SA_application>avr-size _main.elf
   text    data     bss     dec     hex filename
   5294       4    1136    6434    1922 _main.elf

D:\Projects_UPD\SA_application>avr-size main.elf
   text    data     bss     dec     hex filename
   5024       4    1136    6164    1814 main.elf

#TOOLSET = C:/WinAVR/20090313
TOOLSET = C:/WinAVR/20100110
TARGET = avr-
CC = $(TARGET)gcc
OBJCOPY = $(TARGET)objcopy
OBJDUMP = $(TARGET)objdump
SIZE = $(TARGET)size

# if TOOLSET variable set,
# add TOOLSET bin directory first in PATH    
ifneq ($(strip $(TOOLSET)),)
ifeq (,$(findstring;,$(PATH)))
  PATH := $(subst :,,/$(TOOLSET)/bin):$(PATH)
else
  PATH := $(subst /,\,$(TOOLSET)/bin);$(PATH)
endif
export PATH
endif

CFLAGS += -ffunction-sections
CFLAGS += -fdata-sections
CFLAGS += -mcall-prologues

#CFLAGS += -fno-ivopts
CFLAGS += -fno-tree-scev-cprop
CFLAGS += -fno-split-wide-types
CFLAGS += -fno-inline-small-functions

CFLAGS += --param inline-call-cost=0
#CFLAGS += -fno-reorder-blocks
#CFLAGS += -fno-reorder-blocks-and-partition
#CFLAGS += -fno-reorder-functions
#CFLAGS += -fno-toplevel-reorder
CFLAGS += -fno-move-loop-invariants
#CFLAGS += -fno-unroll-loops
#CFLAGS += -fno-unroll-all-loops
#CFLAGS += --param max-unroll-times=0

avr-gcc.exe  -mmcu=atmega16 -Wall -gdwarf-2 -std=gnu99 -DF_CPU=8000000UL -Os -fu
nsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -mcall-prologues
-finline-limit=2 -MD -MP -MT

AVR Memory Usage
----------------
Device: atmega16

Program:    6300 bytes (38.5% Full)
(.text + .data + .bootloader)

Data:         75 bytes (7.3% Full)
(.data + .bss + .noinit)

EEPROM:       57 bytes (11.1% Full)
(.eeprom

AVR Memory Usage
----------------
Device: atmega16

Program:    6238 bytes (38.1% Full)
(.text + .data + .bootloader)

Data:         75 bytes (7.3% Full)
(.data + .bss + .noinit)

EEPROM:       57 bytes (11.1% Full)
(.eeprom)

c:/winavr/lib/gcc/../../avr/include/avr/pgmspace.h:848: error: expected declaration specifiers or '...' before 'size_t'
c:/winavr/lib/gcc/../../avr/include/avr/pgmspace.h:849: error: expected declaration specifiers or '...' before 'size_t'
c:/winavr/lib/gcc/../../avr/include/avr/pgmspace.h:850: error: expected declaration specifiers or '...' before 'size_t'
...
c:/winavr/lib/gcc/../../avr/include/avr/pgmspace.h:861: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'strcspn_P'
c:/winavr/lib/gcc/../../avr/include/avr/pgmspace.h:862: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'strlcat_P'
...

echo OFF
PATH;
set PATH=C:\WinAVR-20090313\bin;C:\WinAVR-20090313\utils\bin;
"E:\portable-pn20101010\pn.exe"
echo WinAVR-20090313

void hd44780::write_data(uint8_t byte)
162:    ff 92           push    r15
164:    0f 93           push    r16
166:    1f 93           push    r17                             <-----------------------------------
168:    8c 01           movw    r16, r24                       <-----------------------------------
16a:    f6 2e           mov    r15, r22
{
    write_tetrade(byte & 0xF0);
16c:    60 7f           andi    r22, 0xF0; 240
16e:    ec df           rcall    .-40    ; 0x148 <_ZN7hd4478013write_tetradeEh>
    write_tetrade(byte << 4);
170:    f2 94           swap    r15
172:    80 ef           ldi    r24, 0xF0; 240
174:    f8 22           and    r15, r24
176:    c8 01           movw    r24, r16                            <-----------------------------------
178:    6f 2d           mov    r22, r15
17a:    e6 df           rcall    .-52    ; 0x148 <_ZN7hd4478013write_tetradeEh>
17c:    8d e3           ldi    r24, 0x3D; 61
17e:    8a 95           dec    r24
180:    f1 f7           brne    .-4     ; 0x17e <_ZN7hd4478010write_dataEh+0x1c>
    _delay_us(50);
    ON(LCD_RS);
182:    c1 9a           sbi    0x18, 1; 24
}
184:    1f 91           pop    r17                        <-----------------------------------
186:    0f 91           pop    r16
188:    ff 90           pop    r15
18a:    08 95           ret

.global    main
    .type    main, @function
main:
.L2:
    lds r24,v
    out 53-32,r24
    rjmp .L2

double res;
//..............
return (int16_t) (lround(res) - 273);

+000007BC:   01C8        MOVW    R24,R16          
+000007BD:   01B7        MOVW    R22,R14          
+000007BE:   D12D        RCALL   PC+0x012E   // lround(res) R23:R22:r25:r24 = 0x01870000
+000007BF:   019C        MOVW    R18,R24       // осторожно, грабли!  
+000007C0:   5121        SUBI    R18,0x11   // - 273      
+000007C1:   4031        SBCI    R19,0x01        
+000007C2:   01C9        MOVW    R24,R18

register volatile uint8_t xL asm("r26");
register volatile uint8_t xH asm("r27");

uint8_t period;

period += 33;
if(period > 100) period -= 100;

  lds r24,period
  subi r24,0xdf // period += 33
  cpi  r24,0x64
  brlo label
  subi r24,0x43 // !!! а должно быть 0x64
label:

  
const uint8_t part_number __attribute__ ((section (".part_number")))='A';

i = pgm_read_byte(&part_number);    
     2ee:    e0 ef           ldi    r30, 0xF0; 240    
     2f0:    ff e3           ldi    r31, 0x3F; 63    
     2f2:    e4 91           lpm    r30, Z+

    lds r25,period
    mov r24,r25
    subi r24,lo8(-(33))
    sts period,r24    
    cpi r24,lo8(101)
    brlo .L3
    subi r25,lo8(-(-67))
    sts period,r25
.L3

#include <avr/io.h>
      
extern uint8_t period;

void foo()
{
    period += 33;
    if(period > 100) period -= 100;
}


uint8_t moo(uint8_t i)
{
    i += 33;
    if(i > 100) i -= 100;
    return i;
}

    .text
.global    foo
    .type    foo, @function
foo:
    lds r25,period
    mov r24,r25
    subi r24,lo8(-(33))
    sts period,r24
    cpi r24,lo8(101)
    brlo .L3
    subi r25,lo8(-(-67))       ; 67 вычитается из _исходного_ значения (+33-100) <=> (-67)
    sts period,r25
.L3:
    ret

.global    moo
    .type    moo, @function
moo:
    subi r24,lo8(-(33))
    cpi r24,lo8(101)
    brlo .L5
    subi r24,lo8(-(-100))
.L5:
    ret

код
const uint8_t part_number __attribute__ ((section (".progmem.part_number")))='A';
const  unsigned long serial_number __attribute__ ((section (".progmem.serial_number"))) = 0x12345678;

маке
LDFLAGS += -Wl,--section-start=.progmem.part_number=$(PART_NUMBER_ADDRESS)
LDFLAGS += -Wl,--section-start=.progmem.serial_number=$(SERIAL_NUMBER_ADDRESS)

HEX
:100050000C9458 0041 78563412 456E7465722063D2

LST
00000054 <part_number>:
      54:    41                                                  A

  i = pgm_read_byte(&part_number);
     2f4:    e4 e5           ldi    r30, 0x54; 84
     2f6:    f0 e0           ldi    r31, 0x00; 0
     2f8:    e4 91           lpm    r30, Z+

/* ATmega88 bootloader linker script */
OUTPUT_FORMAT("elf32-avr","elf32-avr","elf32-avr")
OUTPUT_ARCH(avr:4)
MEMORY
{
application (rx) : ORIGIN = 0, LENGTH = 7K
bootloader (rx) : ORIGIN = 7K, LENGTH = 1K - 4
serial_no (rx) : ORIGIN = 8K-4, LENGTH = 4
ram (rw!x) : ORIGIN = 0x800100, LENGTH = 1K
eeprom (rw!x) : ORIGIN = 0x810000, LENGTH = 512
}
SECTIONS
{
/* Internal text space or external memory. */
.app :
{
__app_start = . ;
/* reserve space */
. = 7K;
__app_end = . ;
} > application
__app_len = . - __app_start;
.text :
{
KEEP(*(.vectors))
/* For data that needs to reside in the lower 64k of progmem. */
*(.progmem.gcc*)
*(.progmem*)
. = ALIGN(2);
__trampolines_start = . ;
/* The jump trampolines for the 16-bit limited relocs will reside here. */
*(.trampolines)
*(.trampolines*)
__trampolines_end = . ;
/* For future tablejump instruction arrays for 3 byte pc devices.
We don't relax jump/call instructions within these sections. */
*(.jumptables)
*(.jumptables*)
/* For code that needs to reside in the lower 128k progmem. */
*(.lowtext)
*(.lowtext*)
__ctors_start = . ;
KEEP(SORT(*)(.ctors))
__ctors_end = . ;
__dtors_start = . ;
KEEP(SORT(*)(.dtors))
__dtors_end = . ;
/* From this point on, we don't bother about wether the insns are
below or above the 16 bits boundary. */
KEEP (*(.init0)) /* Start here after reset. */
KEEP (*(.init1))
KEEP (*(.init2)) /* Clear __zero_reg__, set up stack pointer. */
KEEP (*(.init3))
KEEP (*(.init4)) /* Initialize data and BSS. */
KEEP (*(.init5))
KEEP (*(.init6)) /* C++ constructors. */
KEEP (*(.init7))
KEEP (*(.init8))
KEEP (*(.init9)) /* Call main(). */
*(.text)
. = ALIGN(2);
*(.text.*)
. = ALIGN(2);
KEEP (*(.fini9)) /* _exit() starts here. */
KEEP (*(.fini8))
KEEP (*(.fini7))
KEEP (*(.fini6)) /* C++ destructors. */
KEEP (*(.fini5))
KEEP (*(.fini4))
KEEP (*(.fini3))
KEEP (*(.fini2))
KEEP (*(.fini1))
KEEP (*(.fini0)) /* Infinite loop after program termination. */
_etext = . ;
} > bootloader

.data :
{
PROVIDE (__data_start = .) ;
*(.gnu.linkonce.d*)
*(.rodata)
*(.rodata*)
*(.data)
*(.data*)
. = ALIGN(2);
_edata = . ;
PROVIDE (__data_end = .) ;
} > ram AT > bootloader

.bss :
{
PROVIDE (__bss_start = .) ;
*(.bss)
*(.bss*)
*(COMMON)
PROVIDE (__bss_end = .) ;
} > ram
__data_load_start = LOADADDR(.data);
__data_load_end = __data_load_start + SIZEOF(.data);

.serial_no :
{
KEEP(*(.serial_no))
} > serial_no

/* Global data not cleared after reset. */
.noinit :
{
PROVIDE (__noinit_start = .) ;
*(.noinit*)
PROVIDE (__noinit_end = .) ;
_end = . ;
PROVIDE (__heap_start = .) ;
} > ram

.eeprom :
{
*(.eeprom*)
__eeprom_end = . ;
} > eeprom

/* Stabs debugging sections. */
.stab 0 : { *(.stab) }
.stabstr 0 : { *(.stabstr) }
.stab.excl 0 : { *(.stab.excl) }
.stab.exclstr 0 : { *(.stab.exclstr) }
.stab.index 0 : { *(.stab.index) }
.stab.indexstr 0 : { *(.stab.indexstr) }
.comment 0 : { *(.comment) }

/* DWARF debug sections.
Symbols in the DWARF debugging sections are relative to the beginning
of the section so we begin them at 0. */
/* DWARF 1 */
.debug 0 : { *(.debug) }
.line 0 : { *(.line) }
/* GNU DWARF 1 extensions */
.debug_srcinfo 0 : { *(.debug_srcinfo) }
.debug_sfnames 0 : { *(.debug_sfnames) }
/* DWARF 1.1 and DWARF 2 */
.debug_aranges 0 : { *(.debug_aranges) }
.debug_pubnames 0 : { *(.debug_pubnames) }
/* DWARF 2 */
.debug_info 0 : { *(.debug_info) *(.gnu.linkonce.wi.*) }
.debug_abbrev 0 : { *(.debug_abbrev) }
.debug_line 0 : { *(.debug_line) }
.debug_frame 0 : { *(.debug_frame) }
.debug_str 0 : { *(.debug_str) }
.debug_loc 0 : { *(.debug_loc) }
.debug_macinfo 0 : { *(.debug_macinfo) }
}

__attribute__((section(".serial_no"), noinline))
uint8_t serial_no()
{
    return 0;
}


177                       .section    .serial_no,"ax",@progbits
178                   .global    serial_no
180                   serial_no:
181                   .LFB15:
182                   .LSM26:
183                   /* prologue: function */
184                   /* frame size = 0 */
185                   .LSM27:
186 0000 80E0              ldi r24,lo8(0)
187                   /* epilogue start */
188 0002 0895              ret

uint16_t x;
....
if ((x&1)==0) {...} // случай 1
if (!(x&1))      {...} // случай 2

// случай 1:
   1fd3c:    20 fd           sbrc    r18, 0
   1fd3e:    03 c0           rjmp    .+6      ; 0x1fd46 <main+0x4e4>

// случай 2
   1fd40:    c9 01           movw    r24, r18
   1fd42:    81 70           andi    r24, 0x01; 1
   1fd44:    90 70           andi    r25, 0x00; 0
   1fd46:    89 2b           or    r24, r25
   1fd48:    19 f4           brne    .+6      ; 0x1fd50 <main+0x4ee>

vectors
fixed_boot
progmem
init0
итд итп