diff options
| -rw-r--r-- | subx/012elf.cc | 19 | ||||
| -rwxr-xr-x | subx/ex9 | bin | 147 -> 144 bytes | |||
| -rw-r--r-- | subx/ex9.subx | 12 |
3 files changed, 9 insertions, 22 deletions
diff --git a/subx/012elf.cc b/subx/012elf.cc index 78131090..f82b48aa 100644 --- a/subx/012elf.cc +++ b/subx/012elf.cc @@ -68,26 +68,18 @@ void load_elf_contents(uint8_t* elf_contents, size_t size, int argc, char* argv[ // initialize args on stack // no envp for now -//? cerr << ARGV_POINTER_SEGMENT << " at " << Reg[ESP].u-4 << '\n'; - push(ARGV_POINTER_SEGMENT); -//? cerr << argc-2 << " at " << Reg[ESP].u-4 << '\n'; - push(argc-/*skip 'subx_bin' and 'run'*/2); - // initialize arg data - // we wastefully use 2 whole pages of memory for this + // we wastefully use a separate page of memory for argv uint32_t argv_data = ARGV_DATA_SEGMENT; - uint32_t argv_pointers = ARGV_POINTER_SEGMENT; - for (int i = /*skip 'subx_bin' and 'run'*/2; i < argc; ++i) { -//? cerr << "pointer: " << argv_pointers << " => " << argv_data << '\n'; - write_mem_u32(argv_pointers, argv_data); - argv_pointers += sizeof(uint32_t); - assert(argv_pointers < ARGV_POINTER_SEGMENT + SEGMENT_SIZE); + for (int i = argc-1; i >= /*skip 'subx_bin' and 'run'*/2; --i) { + dbg << "push " << argv_data << end(); + push(argv_data); for (size_t j = 0; j <= strlen(argv[i]); ++j) { -//? cerr << " data: " << argv[i][j] << " (" << NUM(argv[i][j]) << ")\n"; write_mem_u8(argv_data, argv[i][j]); argv_data += sizeof(char); assert(argv_data < ARGV_DATA_SEGMENT + SEGMENT_SIZE); } } + push(argc-/*skip 'subx_bin' and 'run'*/2); } void push(uint32_t val) { @@ -134,7 +126,6 @@ void load_segment_from_program_header(uint8_t* elf_contents, size_t size, uint32 const int CODE_START = 0x08048000; const int SEGMENT_SIZE = 0x1000; const int AFTER_STACK = 0x0804c000; -const int ARGV_POINTER_SEGMENT = 0x0804d000; const int ARGV_DATA_SEGMENT = 0x0804e000; :(code) void initialize_mem() { diff --git a/subx/ex9 b/subx/ex9 index c7f1e9e6..47c79e3c 100755 --- a/subx/ex9 +++ b/subx/ex9 Binary files differdiff --git a/subx/ex9.subx b/subx/ex9.subx index b8482c43..9ea547f1 100644 --- a/subx/ex9.subx +++ b/subx/ex9.subx @@ -2,16 +2,15 @@ # # To run: # $ subx translate ex9.subx ex9 -# $ subx run ex9 abc d e f g h +# $ subx run ex9 abc de fghi # Expected result: # $ echo $? # 3 # length of 'abc' # # At the start of a SubX program: # argc: *ESP -# argv: *(ESP+4) -# argv[0]: *argv ("ex9" in this case) -# argv[1]: *(argv+4) +# argv[0]: *(ESP+4) +# argv[1]: *(ESP+8) # ... # Locals start from ESP-4 downwards. @@ -20,10 +19,7 @@ # op subop mod rm32 base index scale r32 # 1-3 bytes 3 bits 2 bits 3 bits 3 bits 3 bits 2 bits 2 bits 0/1/2/4 bytes 0/1/2/4 bytes # var s = argv[1] (EBX) - # var s = argv - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 3/r32/EBX 4/disp8 . # copy *(ESP+4) to EBX - # s = *(s+4) - 8b/copy 1/mod/*+disp8 3/rm32/EBX . . . 3/r32/EBX 4/disp8 . # copy *(EBX+4) to EBX + 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 3/r32/EBX 8/disp8 . # copy *(ESP+8) to EBX # call ascii_length(EBX) # prepare call 55/push . . . . . . . . # push EBP |