diff options
Diffstat (limited to 'make-hello.e')
| -rw-r--r-- | make-hello.e | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/make-hello.e b/make-hello.e new file mode 100644 index 0000000..55f62d6 --- /dev/null +++ b/make-hello.e @@ -0,0 +1,98 @@ +~ current output point, string pointer +: pack-raw-string + { unpack8 dup } { 3roll swap pack8 swap } while drop drop ; + +: origin 0x08000000 ; + +heap hexdump latest @ .hex space here @ .hex newline +latest @ @ word-heading latest @ @ hexdump +latest @ word-heading latest @ hexdump +: foo + latest @ word-heading latest @ hexdump + ~ s" labels" create + 8 allocate s" labels" variable + ; +foo +latest @ word-heading latest @ hexdump + +s" labels" find .hex bye + +~ ~~ +~ ~~ ELF header +~ ~~ +~ ~~ This is the top-level ELF header, for the entire file. An ELF always +~ ~~ has exactly one of this header, which is always at the start of the file. +~ ~~ +: elf-file-header + 0x7f pack8 s" ELF" pack-raw-string ~ magic number + 2 pack8 ~ 64-bit + 1 pack8 ~ little-endian + 1 pack8 ~ ELF header format v1 + 0 pack8 ~ System-V ABI + 0 pack64 ~ (padding) + + 2 pack16 ~ executable + 0x3e pack16 ~ Intel x86-64 + 1 pack32 ~ ELF format version + + ~ Compute the entry pointer. + origin 0x78 + pack64 ~ entry point + ~ This includes the origin, intentionally. + + 0 pack64 ~ program header offset + ~ We place the program header immediately after the ELF header. This + ~ offset is from the start of the file. + 0 pack64 ~ section header offset + 0 pack32 ~ processor flags + 64 pack16 ~ ELF header size + 56 pack16 ~ program header entry size + 1 pack16 ~ number of program header entries + 0 pack16 ~ section header entry size + 0 pack16 ~ number of section header entries + 0 pack16 ~ section name string table index + ; + +~ ~~ +~ ~~ Program header +~ ~~ +~ ~~ An ELF program header consists of any number of these entries; they are +~ ~~ always consecutive, but may be anywhere in the file. We always have +~ ~~ exactly one, and it's always right after the ELF file header. +~ ~~ +: elf-program-header + 1 pack32 ~ "loadable" segment type + 0x05 pack32 ~ read+execute permission + 0 pack64 ~ offset in file + origin pack64 ~ virtual address + ~ required, but can be anything, subject to alignment + 0 pack64 ~ physical address (ignored) + + ~ Fill in 0 as the file size for now, to avoid uninitialized memory. + 0 pack64 ~ size in file + ~ TODO call use-label here + 0 pack64 ~ size in memory + ~ TODO call use-label here + + 0 pack64 ~ segment alignment + ~ for relocation, but this doesn't apply to us + ; + +: output-start-routine + ~ lit 1 :rax mov-reg64-imm32 + ; + +: all-contents + ~ current output point + elf-file-header + elf-program-header + output-start-routine + ; + +0x1000 allocate dup +~ output memory start, current output point + +all-contents + +~ output memory start, current output point +over - swap sys-write bye + |