build.sh

m68k-none-elf-as -g main.s -o main.o
m68k-none-elf-ld -T main.lds main.o -o main.elf
m68k-none-elf-objcopy -O binary main.elf main.bin

main.lds

OUTPUT_FORMAT("elf32-m68k", "elf32-m68k", "elf32-m68k")
OUTPUT_ARCH(m68k)
MEMORY
{
  rom (arx) : ORIGIN = 0x0000000, LENGTH = 4M
}
SECTIONS
{
  .text :
  {
    . = 0x000;
    KEEP(*(.vectors))
    . = 0x100;
    KEEP(*(.header))
    . = 0x200;
    *(.text)
  } > rom
}

main.s

        .section .vectors

        .long  0x0               /* Reset - initial stack pointer */
        .long  start             /* Reset - initial program counter */
        .long  start             /* Bus error */
        .long  start             /* Address error */
        .long  start             /* Illegal instruction */
        .long  start             /* Divide by zero */
        .long  start             /* CHK exception */
        .long  start             /* TRAPV exception */
        .long  start             /* Privilege violation */
        .long  start             /* Trace */
        .long  start             /* Line 1010 emulator */
        .long  start             /* Line 1111 emulator */
        .long  start             /* reserved */
        .long  start             /* co-processor protocol violation */
        .long  start             /* format error */
        .long  start             /* Uninitialized interrupt */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* reserved */
        .long  start             /* Spurious interrupt */
        .long  start             /* Level 1 interrupt autovector */
        .long  start             /* Level 2 interrupt autovector */
        .long  start             /* Level 3 interrupt autovector */
        .long  start             /* Level 4 interrupt autovector (vdp horizontal) */
        .long  start             /* Level 5 interrupt autovector */
        .long  start             /* Level 6 interrupt autovector (vdp vertical) */
        .long  start             /* Level 7 interrupt autovector */
        .long  start             /* Trap #0 vector */
        .long  start             /* Trap #1 vector */
        .long  start             /* Trap #2 vector */
        .long  start             /* Trap #3 vector */
        .long  start             /* Trap #4 vector */
        .long  start             /* Trap #5 vector */
        .long  start             /* Trap #6 vector */
        .long  start             /* Trap #7 vector */
        .long  start             /* Trap #8 vector */
        .long  start             /* Trap #9 vector */
        .long  start             /* Trap #10 vector */
        .long  start             /* Trap #11 vector */
        .long  start             /* Trap #12 vector */
        .long  start             /* Trap #13 vector */
        .long  start             /* Trap #14 vector */
        .long  start             /* Trap #15 vector */
        .long  start             /* (fp) branch or set on unordered condition */
        .long  start             /* (fp) inexact result */
        .long  start             /* (fp) divide by zero */
        .long  start             /* (fp) underflow */
        .long  start             /* (fp) operand error */
        .long  start             /* (fp) overflow */
        .long  start             /* (fp) signaling nan */
        .long  start             /* (fp) unimplemented data type */
        .long  start             /* mmu configuration error */
        .long  start             /* mmu illegal operation error */
        .long  start             /* mmu access violation error */
        .long  start             /* reserved (not used) */
        .long  start             /* reserved (not used) */
        .long  start             /* reserved (not used) */
        .long  start             /* reserved (not used) */
        .long  start             /* reserved (not used) */

        .section .header

        .ascii "SEGA GENESIS    "
        .ascii "                "   /* Release year.month */
        .ascii "                "   /* Japan Title */
        .ascii "                "   /* */
        .ascii "                "   /* */
        .ascii "                "   /* US Title */
        .ascii "                "   /* */
        .ascii "                "   /* */
        .ascii "              "     /* product #, version */
        .word  0                    /* check sum */
        .ascii "J               "   /* controller */
        .long  0x00000000, 0x0007ffff /* ROM address range */
        .long  0x00ff0000, 0x00ffffff /* RAM address range */
        .ascii "                "   /* */
        .ascii "                "   /* */
        .ascii "                "   /* */
        .ascii "                "   /* */
        .ascii "U               "   /* region support */

        .section .text
start:
        nop
        jmp start