gcc hex, bin file size 줄이기

임베디드용 프로그램은 컴파일된 코드사이즈가 작을 수 록 좋다.

보통 printf등의 함수를 사용하면, 수십kb 이상 파일크기가 증가한다.

약 68kbyte인 상태

================= Generate binary file Generate hex file main.o : section size addr .isr_vector 388 134217728 .text 67288 134218116 .eh_frame 4 134285404 .ARM 8 134285408 .ARM.attributes 41 0 .init_array 8 134285416 .fini_array 4 134285424 .data 1204 536870912 .jcr 4 536872116 .fsmc_sram_data 0 1677721600 .fsmc_sram_bss 0 1677721600 .fsmc_sram_perma 0 1677721600 .bss 2128 536872120 ._user_heap_stack 1536 536874248 .factory_values 0 135264256 .debug_info 117485 0 .debug_abbrev 3591 0 .debug_loc 114940 0 .debug_aranges 176 0 .debug_ranges 21624 0 .debug_line 29503 0 .debug_str 20683 0 .comment 112 0 .debug_frame 14992 0 Total 395719 text data bss dec hex filename 67688 1220 3664 72572 11b7c main.o D 드라이브의 볼륨: D 볼륨 일련 번호: 1473-2495 D:\ARM\DP3000\DP3000 디렉터리 2016-09-09 오후 04:57 68,908 main.bin

printf함수대신, puts등을 여러번 사용하여 구현하기도 한다.

또는 %d, %s등만 구현이 되는 간단한 printf함수를 만들어 사용하기도 한다.

또한, printf, puts등에 사용된 문자열도 코드사이즈 증가에 한몫한다.

가는하면, 디버깅이 끝나면, 주석문으로 처리하는것이 좋다.

컴파일된 함수의 기계어 코드사이즈를 확인할 수 있는 방법

Usage: arm-none-eabi-objdump Display information from object . At least one of the following switches must be given: -a, --archive-headers Display archive header information -f, --file-headers Display the contents of the overall file header -p, --private-headers Display object format specific file header contents -P, --private=OPT,OPT... Display object format specific contents -h, --[section-]headers Display the contents of the section headers -x, --all-headers Display the contents of all headers -d, --disassemble Display assembler contents of executable sections -D, --disassemble-all Display assembler contents of all sections -S, --source Intermix source code with disassembly -s, --full-contents Display the full contents of all sections requested -g, --debugging Display debug information in object file -e, --debugging-tags Display debug information using ctags style -G, --stabs Display (in raw form) any STABS info in the file -W[lLiaprmfFsoRt] or --dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames, =frames-interp,=str,=loc,=Ranges,=pubtypes, =gdb_index,=trace_info,=trace_abbrev,=trace_aranges, =addr,=cu_index] Display DWARF info in the file -t, --syms Display the contents of the symbol table(s) -T, --dynamic-syms Display the contents of the dynamic symbol table -r, --reloc Display the relocation entries in the file -R, --dynamic-reloc Display the dynamic relocation entries in the file @ Read options from -v, --version Display this program's version number -i, --info List object formats and architectures supported -H, --help Display this information

arm-none-eabi-objdump -S -h -d main.o > ..\main.lst Sections: Idx Name Size VMA LMA File off Algn 0 .isr_vector 00000184 08000000 08000000 00008000 2**0 CONTENTS, ALLOC, LOAD, READONLY, DATA 1 .text 000106d8 08000184 08000184 00008184 2**2 CONTENTS, ALLOC, LOAD, READONLY, CODE 2 .eh_frame 00000004 0801085c 0801085c 0001885c 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 3 .ARM 00000008 08010860 08010860 00018860 2**2 CONTENTS, ALLOC, LOAD, READONLY, DATA 4 .ARM.attributes 00000029 00000000 00000000 000204b8 2**0 CONTENTS, READONLY 5 .init_array 00000008 08010868 08010868 00018868 2**2 CONTENTS, ALLOC, LOAD, DATA 6 .fini_array 00000004 08010870 08010870 00018870 2**2 CONTENTS, ALLOC, LOAD, DATA 7 .data 000004b4 20000000 08010874 00020000 2**3 CONTENTS, ALLOC, LOAD, DATA 8 .jcr 00000004 200004b4 08010d28 000204b4 2**2 CONTENTS, ALLOC, LOAD, DATA 9 .fsmc_sram_data 00000000 64000000 64000000 000204e1 2**0 CONTENTS 10 .fsmc_sram_bss 00000000 64000000 64000000 000204e1 2**0 CONTENTS 11 .fsmc_sram_perma 00000000 64000000 64000000 000204e1 2**0 CONTENTS 12 .bss 00000850 200004b8 200004b4 000204b8 2**2 ALLOC 13 ._user_heap_stack 00000600 20000d08 2001fa00 00020d08 2**0 ALLOC 14 .factory_values 00000000 080ff800 080ff800 000204e1 2**0 CONTENTS 15 .debug_info 0001caed 00000000 00000000 000204e1 2**0 CONTENTS, READONLY, DEBUGGING 16 .debug_abbrev 00000e07 00000000 00000000 0003cfce 2**0 CONTENTS, READONLY, DEBUGGING 17 .debug_loc 0001c0fc 00000000 00000000 0003ddd5 2**0 CONTENTS, READONLY, DEBUGGING 18 .debug_aranges 000000b0 00000000 00000000 00059ed8 2**3 CONTENTS, READONLY, DEBUGGING 19 .debug_ranges 00005478 00000000 00000000 00059f88 2**3 CONTENTS, READONLY, DEBUGGING 20 .debug_line 0000733f 00000000 00000000 0005f400 2**0 CONTENTS, READONLY, DEBUGGING 21 .debug_str 000050cb 00000000 00000000 0006673f 2**0 CONTENTS, READONLY, DEBUGGING 22 .comment 00000070 00000000 00000000 0006b80a 2**0 CONTENTS, READONLY 23 .debug_frame 00003a90 00000000 00000000 0006b87c 2**2 CONTENTS, READONLY, DEBUGGING Disassembly of section .text: 08000184 <__do_global_dtors_aux>: 8000184: b510 push {r4, lr} 8000186: 4c05 ldr r4, [pc, #20] ; (800019c <__do_global_dtors_aux+0x18>) 8000188: 7823 ldrb r3, [r4, #0] 800018a: b933 cbnz r3, 800019a <__do_global_dtors_aux+0x16> 800018c: 4b04 ldr r3, [pc, #16] ; (80001a0 <__do_global_dtors_aux+0x1c>) 800018e: b113 cbz r3, 8000196 <__do_global_dtors_aux+0x12> 8000190: 4804 ldr r0, [pc, #16] ; (80001a4 <__do_global_dtors_aux+0x20>) 8000192: f3af 8000 nop.w 8000196: 2301 movs r3, #1 8000198: 7023 strb r3, [r4, #0] 800019a: bd10 pop {r4, pc} 800019c: 200004b8 .word 0x200004b8 80001a0: 00000000 .word 0x00000000 80001a4: 0801085c .word 0x0801085c 080001a8 <frame_dummy>: 80001a8: 4b08 ldr r3, [pc, #32] ; (80001cc <frame_dummy+0x24>) 80001aa: b510 push {r4, lr} 80001ac: b11b cbz r3, 80001b6 <frame_dummy+0xe> 80001ae: 4808 ldr r0, [pc, #32] ; (80001d0 <frame_dummy+0x28>) 80001b0: 4908 ldr r1, [pc, #32] ; (80001d4 <frame_dummy+0x2c>) 80001b2: f3af 8000 nop.w 80001b6: 4808 ldr r0, [pc, #32] ; (80001d8 <frame_dummy+0x30>) 80001b8: 6803 ldr r3, [r0, #0] 80001ba: b903 cbnz r3, 80001be <frame_dummy+0x16> 80001bc: bd10 pop {r4, pc} 80001be: 4b07 ldr r3, [pc, #28] ; (80001dc <frame_dummy+0x34>) 80001c0: 2b00 cmp r3, #0 80001c2: d0fb beq.n 80001bc <frame_dummy+0x14> 80001c4: e8bd 4010 ldmia.w sp!, {r4, lr} 80001c8: 4718 bx r3 80001ca: bf00 nop 80001cc: 00000000 .word 0x00000000 80001d0: 0801085c .word 0x0801085c 80001d4: 200004bc .word 0x200004bc 80001d8: 200004b4 .word 0x200004b4 80001dc: 00000000 .word 0x00000000 080001e0 <_mainCRTStartup>: 80001e0: 4b15 ldr r3, [pc, #84] ; (8000238 <_mainCRTStartup+0x58>) 80001e2: 2b00 cmp r3, #0 80001e4: bf08 it eq 80001e6: 4b13 ldreq r3, [pc, #76] ; (8000234 <_mainCRTStartup+0x54>) 80001e8: 469d mov sp, r3 80001ea: f5a3 3a80 sub.w sl, r3, #65536 ; 0x10000 80001ee: 2100 movs r1, #0 80001f0: 468b mov fp, r1 80001f2: 460f mov r7, r1 80001f4: 4813 ldr r0, [pc, #76] ; (8000244 <_mainCRTStartup+0x64>) 80001f6: 4a14 ldr r2, [pc, #80] ; (8000248 <_mainCRTStartup+0x68>) 80001f8: 1a12 subs r2, r2, r0 80001fa: f010 f819 bl 8010230 <memset> 80001fe: 4b0f ldr r3, [pc, #60] ; (800023c <_mainCRTStartup+0x5c>) 8000200: 2b00 cmp r3, #0 8000202: d000 beq.n 8000206 <_mainCRTStartup+0x26> 8000204: 4798 blx r3 8000206: 4b0e ldr r3, [pc, #56] ; (8000240 <_mainCRTStartup+0x60>) 8000208: 2b00 cmp r3, #0 800020a: d000 beq.n 800020e <_mainCRTStartup+0x2e> 800020c: 4798 blx r3 800020e: 2000 movs r0, #0 8000210: 2100 movs r1, #0 8000212: 0004 movs r4, r0 8000214: 000d movs r5, r1 8000216: 480d ldr r0, [pc, #52] ; (800024c <_mainCRTStartup+0x6c>) 8000218: 2800 cmp r0, #0 800021a: d002 beq.n 8000222 <_mainCRTStartup+0x42> 800021c: 480c ldr r0, [pc, #48] ; (8000250 <_mainCRTStartup+0x70>) 800021e: f010 f8f7 bl 8010410 <atexit> 8000222: f00f ffdd bl 80101e0 <__libc_init_array> 8000226: 0020 movs r0, r4 8000228: 0029 movs r1, r5 800022a: f00f ff5d bl 80100e8 <main> 800022e: f00f ffc7 bl 80101c0 <exit> 8000232: bf00 nop 8000234: 00080000 .word 0x00080000 ... 8000244: 200004b8 .word 0x200004b8 8000248: 20000d08 .word 0x20000d08 800024c: 08010411 .word 0x08010411 8000250: 0801041d .word 0x0801041d

symbol table에서 각 함수의 크기를 확인할 수 있다.

크기가 큰 함수나, 불필요한 함수는 제거하자.

arm-none-eabi-objdump -S -h -d -t main.o > ..\main.lst SYMBOL TABLE: 08000000 l d .isr_vector 00000000 .isr_vector 08000184 l d .text 00000000 .text 0801085c l d .eh_frame 00000000 .eh_frame 08010860 l d .ARM 00000000 .ARM 00000000 l d .ARM.attributes 00000000 .ARM.attributes 08010868 l d .init_array 00000000 .init_array 08010870 l d .fini_array 00000000 .fini_array 20000000 l d .data 00000000 .data 200004b4 l d .jcr 00000000 .jcr 64000000 l d .fsmc_sram_data 00000000 .fsmc_sram_data 64000000 l d .fsmc_sram_bss 00000000 .fsmc_sram_bss 64000000 l d .fsmc_sram_perma 00000000 .fsmc_sram_perma 200004b8 l d .bss 00000000 .bss 20000d08 l d ._user_heap_stack 00000000 ._user_heap_stack 080ff800 l d .factory_values 00000000 .factory_values 00000000 l d .debug_info 00000000 .debug_info 00000000 l d .debug_abbrev 00000000 .debug_abbrev 00000000 l d .debug_loc 00000000 .debug_loc 00000000 l d .debug_aranges 00000000 .debug_aranges 00000000 l d .debug_ranges 00000000 .debug_ranges 00000000 l d .debug_line 00000000 .debug_line 00000000 l d .debug_str 00000000 .debug_str 00000000 l d .comment 00000000 .comment 00000000 l d .debug_frame 00000000 .debug_frame 00000000 l df *ABS* 00000000 C:\DOCUME~1\a\LOCALS~1\Temp\ccG34aLa.o 08010184 l .text 00000000 LoopCopyDataInit 0801017c l .text 00000000 CopyDataInit 08010198 l .text 00000000 LoopFillZerobss 08010192 l .text 00000000 FillZerobss 080101bc l .text 00000000 Infinite_Loop 00000000 l df *ABS* 00000000 d:/arm/bin/../lib/gcc/arm-none-eabi/4.9.3/armv7-m/crti.o 00000000 l df *ABS* 00000000 crtstuff.c 0801085c l O .eh_frame 00000000 __EH_FRAME_BEGIN__ 200004b4 l O .jcr 00000000 __JCR_LIST__ 08000184 l F .text 00000000 __do_global_dtors_aux 200004b8 l .bss 00000000 completed.8108