devkitProのgccはリンカスクリプトを通してプログラムの配置を決定しています。ファイルは「C:\devkitPro\devkitARM\arm-none-eabi\lib」の「gba_cart.ld」 、マルチブート用は「gba_mb.ld」になります。短いので全文を以下に記載します。わけわからないと思いますが、ある程度は舐めるように読んでください。全ては理解できないものの一部は馴染みのある記載をしています。
/* Linker Script Original v1.3 by Jeff Frohwein */ /* v1.0 - Original release */ /* v1.1 - Added proper .data section support */ /* v1.2 - Added support for c++ & iwram overlays */ /* - Major contributions by Jason Wilkins. */ /* v1.3 - .ewram section now can be used when */ /* compiling for MULTIBOOT mode. This fixes */ /* malloc() in DevKitAdvance which depends */ /* on __eheap_start instead of end to define*/ /* the starting location of heap space. */ /* External global variable __gba_iwram_heap*/ /* support added to allow labels end, _end, */ /* & __end__ to point to end of iwram or */ /* the end of ewram. */ /* Additions by WinterMute */ /* v1.4 - .sbss section added for unitialised */ /* data in ewram */ /* v1.5 - padding section added to stop EZF */ /* stripping important data */ /* This file is released into the public domain */ /* for commercial or non-commercial use with no */ /* restrictions placed upon it. */ /* NOTE!!!: This linker script defines the RAM & */ /* ROM start addresses. In order for it to work */ /* properly, remove -Ttext and -Tbss linker */ /* options from your makefile if they are */ /* present. */ /* You can use the following to view section */ /* addresses in your .elf file: */ /* objdump -h file.elf */ /* Please note that empty sections may incorrectly*/ /* list the lma address as the vma address for */ /* some versions of objdump. */ OUTPUT_FORMAT("elf32-littlearm", "elf32-bigarm", "elf32-littlearm") OUTPUT_ARCH(arm) ENTRY(_start) /* SEARCH_DIR(/bin/arm); */ /* The linker script function "var1 += var2;" sometimes */ /* reports incorrect values in the *.map file but the */ /* actual value it calculates is usually, if not always, */ /* correct. If you leave out the ". = ALIGN(4);" at the */ /* end of each section then the return value of SIZEOF() */ /* is sometimes incorrect and "var1 += var2;" appears to */ /* not work as well. "var1 += var2" style functions are */ /* avoided below as a result. */ MEMORY { rom : ORIGIN = 0x08000000, LENGTH = 32M iwram : ORIGIN = 0x03000000, LENGTH = 32K ewram : ORIGIN = 0x02000000, LENGTH = 256K } __text_start = ORIGIN(rom); __eheap_end = ORIGIN(ewram) + LENGTH(ewram); __iwram_start = ORIGIN(iwram); __iwram_top = ORIGIN(iwram) + LENGTH(iwram);; __sp_irq = __iwram_top - 0x060; __sp_usr = __sp_irq - 0x0a0; __irq_flags = 0x03007ff8; SECTIONS { . = __text_start; .crt0 : { KEEP (*(.crt0)) . = ALIGN(4); } >rom =0xff .init : { KEEP (*(SORT_NONE(.init))) } >rom .plt : { *(.plt) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom .text : /* ALIGN (4): */ { *(EXCLUDE_FILE (*.iwram*) .text*) *(.gnu.linkonce.t.*) KEEP (*(.text.*personality*)) /* .gnu.warning sections are handled specially by elf32.em. */ *(.gnu.warning) *(.glue_7t) *(.glue_7) *(.vfp11_veneer) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0xff __text_end = .; .fini : { KEEP (*(.fini)) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom =0 .rodata : { *(.rodata) *all.rodata*(*) *(.roda) *(.rodata.*) *(.gnu.linkonce.r*) SORT(CONSTRUCTORS) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0xff .ARM.extab : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >rom __exidx_start = .; .ARM.exidx : { *(.ARM.exidx* .gnu.linkonce.armexidx.*) } >rom __exidx_end = .; .ctors : { /* gcc uses crtbegin.o to find the start of the constructors, so we make sure it is first. Because this is a wildcard, it doesn't matter if the user does not actually link against crtbegin.o; the linker won't look for a file to match a wildcard. The wildcard also means that it doesn't matter which directory crtbegin.o is in. */ KEEP (*crtbegin.o(.ctors)) KEEP (*(EXCLUDE_FILE (*crtend.o) .ctors)) KEEP (*(SORT(.ctors.*))) KEEP (*(.ctors)) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0 .dtors : { KEEP (*crtbegin.o(.dtors)) KEEP (*(EXCLUDE_FILE (*crtend.o) .dtors)) KEEP (*(SORT(.dtors.*))) KEEP (*(.dtors)) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0 .eh_frame : { KEEP (*(.eh_frame)) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0 .gcc_except_table : { *(.gcc_except_table) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } >rom = 0 __iwram_lma = .; .iwram __iwram_start : AT (__iwram_lma) { __iwram_start__ = ABSOLUTE(.) ; *(.iwram .iwram*) *iwram.*(.text* .data*) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ __iwram_end__ = ABSOLUTE(.) ; } >iwram = 0xff __data_lma = __iwram_lma + SIZEOF(.iwram) ; .bss ALIGN(4) (NOLOAD) : { __bss_start = ABSOLUTE(.); __bss_start__ = ABSOLUTE(.); *(.dynbss) *(.gnu.linkonce.b*) *(.bss*) *(COMMON) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ __bss_end__ = ABSOLUTE(.); } AT>iwram .data ALIGN(4) : AT (__data_lma) { __data_start__ = ABSOLUTE(.); *(.data*) *(.gnu.linkonce.d*) CONSTRUCTORS . = ALIGN(4); } >iwram = 0xff __preinit_lma = __data_lma + SIZEOF(.data); .preinit_array ALIGN(4) : AT (__preinit_lma) { __preinit_array_start = ABSOLUTE(.); KEEP (*(.preinit_array)) __preinit_array_end = ABSOLUTE(.); } >iwram __init_lma = __preinit_lma + SIZEOF(.preinit_array); .init_array ALIGN(4) : AT (__init_lma) { __init_array_start = ABSOLUTE(.); KEEP (*(SORT(.init_array.*))) KEEP (*(.init_array)) __init_array_end = ABSOLUTE(.); } >iwram __fini_lma = __init_lma + SIZEOF(.init_array); .fini_array ALIGN(4) : AT (__fini_lma) { __fini_array_start = ABSOLUTE(.); KEEP (*(SORT(.fini_array.*))) KEEP (*(.fini_array)) __fini_array_end = ABSOLUTE(.); } >iwram __jcr_lma = __fini_lma + SIZEOF(.fini_array); .jcr ALIGN(4) : AT (__jcr_lma) { KEEP (*(.jcr)) } >iwram __data_end__ = ABSOLUTE(.); __iwram_overlay_lma = __jcr_lma + SIZEOF(.jcr); __iwram_overlay_start = . ; OVERLAY ALIGN(4) : NOCROSSREFS AT (__iwram_overlay_lma) { .iwram0 { *(.iwram0) . = ALIGN(4);} .iwram1 { *(.iwram1) . = ALIGN(4);} .iwram2 { *(.iwram2) . = ALIGN(4);} .iwram3 { *(.iwram3) . = ALIGN(4);} .iwram4 { *(.iwram4) . = ALIGN(4);} .iwram5 { *(.iwram5) . = ALIGN(4);} .iwram6 { *(.iwram6) . = ALIGN(4);} .iwram7 { *(.iwram7) . = ALIGN(4);} .iwram8 { *(.iwram8) . = ALIGN(4);} .iwram9 { *(.iwram9) . = ALIGN(4);} }>iwram = 0xff __iwram_overlay_end = . ; __ewram_lma = __iwram_overlay_lma + (__iwram_overlay_end - __iwram_overlay_start) ; __iheap_start = . ; __ewram_start = ORIGIN(ewram); .ewram __ewram_start : AT (__ewram_lma) { *(.ewram*) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ __ewram_end = ABSOLUTE(.); }>ewram = 0xff __pad_lma = __ewram_lma + SIZEOF(.ewram); .sbss ALIGN(4)(NOLOAD): { __sbss_start__ = ABSOLUTE(.); *(.sbss*) . = ALIGN(4); __sbss_end__ = ABSOLUTE(.); __end__ = ABSOLUTE(.); __eheap_start = ABSOLUTE(.); } AT>ewram /* EZF Advance strips trailing 0xff bytes, add a pad section so nothing important is removed */ .pad ALIGN(4) : AT (__pad_lma) { LONG(0x52416b64) LONG(0x4d) . = ALIGN(4); /* REQUIRED. LD is flaky without it. */ } = 0xff __rom_end__ = __pad_lma + SIZEOF(.pad); /* 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) } .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) } /* SGI/MIPS DWARF 2 extensions */ .debug_weaknames 0 : { *(.debug_weaknames) } .debug_funcnames 0 : { *(.debug_funcnames) } .debug_typenames 0 : { *(.debug_typenames) } .debug_varnames 0 : { *(.debug_varnames) } .stack 0x80000 : { _stack = .; *(.stack) } /* These must appear regardless of . */ .note.gnu.arm.ident 0 : { KEEP (*(.note.gnu.arm.ident)) } .ARM.attributes 0 : { KEEP (*(.ARM.attributes)) } /DISCARD/ : { *(.note.GNU-stack) } }
MEMORY { rom : ORIGIN = 0x08000000, LENGTH = 32M iwram : ORIGIN = 0x03000000, LENGTH = 32K ewram : ORIGIN = 0x02000000, LENGTH = 256K } __text_start = ORIGIN(rom); __eheap_end = ORIGIN(ewram) + LENGTH(ewram); __iwram_start = ORIGIN(iwram); __iwram_top = ORIGIN(iwram) + LENGTH(iwram);; __sp_irq = __iwram_top - 0x060; __sp_usr = __sp_irq - 0x0a0; __irq_flags = 0x03007ff8;