diff options
| -rw-r--r-- | subx/011run.cc | 10 | ||||
| -rw-r--r-- | subx/ex7.subx | 50 |
2 files changed, 30 insertions, 30 deletions
diff --git a/subx/011run.cc b/subx/011run.cc index 218f4e16..5d2aab8a 100644 --- a/subx/011run.cc +++ b/subx/011run.cc @@ -61,7 +61,9 @@ cerr << " syntax\n"; # opcode ModR/M SIB displacement immediate # instruction mod, reg, Reg/Mem bits scale, index, base # 1-3 bytes 0/1 byte 0/1 byte 0/1/2/4 bytes 0/1/2/4 bytes - 05 0a 0b 0c 0d # add 0x0d0c0b0a to EAX + 05 . . . 0a 0b 0c 0d # add 0x0d0c0b0a to EAX +# (The single periods are just to help the eye track long gaps between +# columns, and are otherwise ignored.) # This program, when run, causes the following events in the trace: +load: 0x00000001 -> 05 @@ -132,6 +134,8 @@ void parse(istream& fin, program& out) { string word_data; lin >> word_data; if (word_data.empty()) continue; + if (word_data[0] == '#') break; // comment + if (word_data == ".") continue; // comment token if (word_data == "==") { if (!l.empty()) { assert(!out.segments.empty()); @@ -149,10 +153,6 @@ void parse(istream& fin, program& out) { // todo: line metadata break; } - if (word_data[0] == '#') { - // comment - break; - } w.push_back(word()); w.back().original = word_data; istringstream win(word_data); diff --git a/subx/ex7.subx b/subx/ex7.subx index 4474e110..e312edbe 100644 --- a/subx/ex7.subx +++ b/subx/ex7.subx @@ -15,73 +15,73 @@ # main: # prepare to make a call # 54 - 55/push # push EBP + 55/push . . . . . . . . # push EBP # 55 - 89/copy 3/mod/direct 5/rm32/EBP 4/r32/ESP # copy ESP to EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP # 57 # factorial(5) - 68/push 5/imm32 # push 5 + 68/push . . . . . . . 5/imm32 # push 5 # 5c - e8/call factorial/disp32 + e8/call . . . . . . factorial/disp32 # 61 # discard arg - 5a/pop # pop into EDX + 5a/pop . . . . . . . . # pop into EDX # 62 # clean up after call - 89/copy 3/mod/direct 4/rm32/ESP 5/r32/EBP # copy EBP to ESP + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP # 64 - 5d/pop # pop to EBP + 5d/pop . . . . . . . . # pop to EBP # exit(EAX) # 65 - 89/copy 3/mod/direct 3/rm32/EBX 0/r32/EAX # copy EAX to EBX + 89/copy 3/mod/direct 3/rm32/EBX . . . 0/r32/EAX . . # copy EAX to EBX # 67 - b8/copy 1/imm32 # copy 1 to EAX + b8/copy . . . . . . . 1/imm32 # copy 1 to EAX # 6c - cd/syscall 0x80/imm8 # int 80h + cd/syscall . . . . . . . 0x80/imm8 # int 80h # factorial(n) # 6e factorial: # initialize n - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 # copy *(ESP+4) to EDX + 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX # 72 # initialize EAX to 1 (base case) - b8/copy 1/imm32 # copy 1 to EAX + b8/copy . . . . . . . 1/imm32 # copy 1 to EAX # 77 # if (n <= 1) jump exit - 81 7/subop/compare 3/mod/direct 2/rm32/EDX 1/imm32 # compare EDX with 1 + 81 7/subop/compare 3/mod/direct 2/rm32/EDX . . . . . 1/imm32 # compare EDX with 1 # 7d - 7e/jump-if factorial:exit/disp8 # jump if <= to exit + 7e/jump-if . . . . . . factorial:exit/disp8 # jump if <= to exit # 7f # EBX: n-1 - 89/copy 3/mod/direct 3/rm32/EBX 2/r32/EDX # copy EDX to EBX + 89/copy 3/mod/direct 3/rm32/EBX . . . 2/r32/EDX . . # copy EDX to EBX # 81 - 81 5/subop/subtract 3/mod/direct 3/rm32/EBX 1/imm32 # subtract 1 from EBX + 81 5/subop/subtract 3/mod/direct 3/rm32/EBX . . . . . 1/imm32 # subtract 1 from EBX # 87 # prepare call - 55/push # push EBP + 55/push . . . . . . . . # push EBP # 88 - 89/copy 3/mod/direct 5/rm32/EBP 4/r32/ESP # copy ESP to EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP # EAX: factorial(n-1) # 8a - 53/push # push EBX + 53/push . . . . . . . . # push EBX # 8b - e8/call factorial/disp32 + e8/call . . . . . . factorial/disp32 # 90 # discard arg - 5e/pop # pop into ESI + 5e/pop . . . . . . . . # pop into ESI # 91 # clean up after call - 89/copy 3/mod/direct 4/rm32/ESP 5/r32/EBP # copy EBP to ESP + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP # 93 - 5d/pop # pop to EBP + 5d/pop . . . . . . . . # pop to EBP # 94 # refresh n - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 # copy *(ESP+4) to EDX + 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 2/r32/EDX 4/disp8 . # copy *(ESP+4) to EDX # 98 # return n * factorial(n-1) - 0f af/multiply 3/mod/direct 2/rm32/EDX 0/r32/EAX # multiply EDX (n) into EAX (factorial(n-1)) + 0f af/multiply 3/mod/direct 2/rm32/EDX . . . 0/r32/EAX . . # multiply EDX (n) into EAX (factorial(n-1)) # TODO: check for overflow # 9b factorial:exit: |