diff options
| author | iximeow <me@iximeow.net> | 2015-09-28 03:33:19 -0700 |
|---|---|---|
| committer | iximeow <me@iximeow.net> | 2015-09-28 03:36:28 -0700 |
| commit | 74057dac1d460574f0b7edb89e9e4125a69c885a (patch) | |
| tree | 8bd43ea888b33272d21719c7f97c51db1bc58c57 | |
| parent | 4f63bab19769e2aedb9721322501cecf9934156c (diff) | |
add awful support for non-0x7e00 start, prefix real start address to kernel
| -rw-r--r-- | bootloader.asm | 13 | ||||
| -rwxr-xr-x | build_helpers/compile.sh | 14 |
2 files changed, 19 insertions, 8 deletions
diff --git a/bootloader.asm b/bootloader.asm index c9ed98b..7d218eb 100644 --- a/bootloader.asm +++ b/bootloader.asm @@ -13,7 +13,7 @@ start: call verify_read mov si, READ_NERR call write_str - jmp 0x7e00 + jmp word [0x7dfc] jmp hang read_err: @@ -23,17 +23,18 @@ hang: jmp hang verify_read: + mov bx, word [0x7dfc] mov al, 0x66 - cmp al, [0x7e00] + cmp al, byte [bx] jne read_err mov al, 0x55 - cmp al, [0x7e01] + cmp al, byte [bx+1] jne read_err mov al, 0x66 - cmp al, [0x7e02] + cmp al, byte [bx+2] jne read_err mov al, 0x89 - cmp al, [0x7e03] + cmp al, byte [bx+3] jne read_err ret @@ -106,7 +107,7 @@ LBA_DISK_READ_PACKET: db 0x10 db 0 dw 32 ; number of blocks to read, reset to # actually read when done - dw 0x7e00 ; read destination address + dw 0x7dfc ; read destination address dw 0x0000 dd 1 ; lba to read from dd 0 ; for extended lba adresses (not really used here) diff --git a/build_helpers/compile.sh b/build_helpers/compile.sh index 40cd293..f00549f 100755 --- a/build_helpers/compile.sh +++ b/build_helpers/compile.sh @@ -10,8 +10,18 @@ OUTNAME="src._kernel._main" echo -n "[*] Building '$INPATH' to 'tmp/$OUTNAME'... " gcc -T linker.ld -m32 -Wl,--build-id=none -nostartfiles -nostdlib -ffreestanding $INPATH -o "tmp/$OUTNAME".o echo " OK!" +echo -n "[+] Start address is... " +BIN_START=$(objdump tmp/src._kernel._main.o -f | grep start | cut -b 15-) +echo "$BIN_START" +# this actually writes three extra nulls, not sure why... +echo "$BIN_START" | xxd -r - | od -t x --endian=little | head | xxd -r - > "bin/$OUTNAME".bin echo -n "[+] Stripping unnecessary sections... " -objcopy -R .note.gnu.build-id -R .comment -O binary "tmp/$OUTNAME".o "bin/$OUTNAME".bin +objcopy -R .note.gnu.build-id -R .comment -O binary "tmp/$OUTNAME".o "tmp/converted_$OUTNAME".bin echo " OK!" -rm "tmp/$OUTNAME".o + +echo -n "[+] Joining kernel and start address... " +# adjust for the three extra nulls above +dd if="tmp/converted_$OUTNAME".bin of="bin/$OUTNAME".bin seek=4 oflag=seek_bytes conv=notrunc 2>/dev/null +echo " OK!" +#rm "tmp/$OUTNAME".o |