From 608a7fa8d0faf9a3e3d182d9eabe969804443aab Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Fri, 7 Sep 2018 15:08:54 -0700 Subject: 4536 --- html/subx/ex7.subx.html | 124 ------------------------------------------------ 1 file changed, 124 deletions(-) delete mode 100644 html/subx/ex7.subx.html (limited to 'html/subx/ex7.subx.html') diff --git a/html/subx/ex7.subx.html b/html/subx/ex7.subx.html deleted file mode 100644 index baa9076f..00000000 --- a/html/subx/ex7.subx.html +++ /dev/null @@ -1,124 +0,0 @@ - - - - -Mu - subx/ex7.subx - - - - - - - - - - -
- 1 ## compute the factorial of 5, and return the result in the exit code
- 2 #
- 3 # To run:
- 4 #   $ subx translate ex7.subx ex7
- 5 #   $ subx run ex7
- 6 # Expected result:
- 7 #   $ echo $?
- 8 #   120
- 9 
-10 == 0x08048054  # code segment, after leaving room for ELF header
-11 # instruction                     effective address                                                   operand     displacement    immediate
-12 # op          subop               mod             rm32          base        index         scale       r32
-13 # 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
-14 
-15 # main:
-16   # prepare to make a call
-17   55/push                         .               .             .           .             .           .           .               .                 # push EBP
-18   89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-19   # factorial(5)
-20   68/push                         .               .             .           .             .           .           .               5/imm32           # push 5
-21   e8/call                         .               .             .           .             .           .           factorial/disp32
-22   # discard arg
-23   5a/pop                          .               .             .           .             .           .           .               .                 # pop into EDX
-24   # clean up after call
-25   89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-26   5d/pop                          .               .             .           .             .           .           .               .                 # pop to EBP
-27 
-28   # exit(EAX)
-29   89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           0/r32/EAX   .               .                 # copy EAX to EBX
-30   b8/copy                         .               .             .           .             .           .           .               1/imm32           # copy 1 to EAX
-31   cd/syscall                      .               .             .           .             .           .           .               0x80/imm8         # int 80h
-32 
-33 # factorial(n)
-34 factorial:
-35   # initialize n
-36   8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/ESP  4/index/none              2/r32/EDX   4/disp8         .                 # copy *(ESP+4) to EDX
-37   # initialize EAX to 1 (base case)
-38   b8/copy                         .               .             .           .             .           .           .               1/imm32           # copy 1 to EAX
-39   # if (n <= 1) jump exit
-40   81          7/subop/compare     3/mod/direct    2/rm32/EDX    .           .             .           .           .               1/imm32           # compare EDX with 1
-41   7e/jump-if-<=                   .               .             .           .             .           .           $factorial:exit/disp8             # jump if <= to $factorial:exit
-42   # EBX: n-1
-43   89/copy                         3/mod/direct    3/rm32/EBX    .           .             .           2/r32/EDX   .               .                 # copy EDX to EBX
-44   81          5/subop/subtract    3/mod/direct    3/rm32/EBX    .           .             .           .           .               1/imm32           # subtract 1 from EBX
-45   # prepare call
-46   55/push                         .               .             .           .             .           .           .               .                 # push EBP
-47   89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
-48   # EAX: factorial(n-1)
-49   53/push                         .               .             .           .             .           .           .               .                 # push EBX
-50   e8/call                         .               .             .           .             .           .           factorial/disp32
-51   # discard arg
-52   5e/pop                          .               .             .           .             .           .           .               .                 # pop into ESI
-53   # clean up after call
-54   89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
-55   5d/pop                          .               .             .           .             .           .           .               .                 # pop to EBP
-56   # refresh n
-57   8b/copy                         1/mod/*+disp8   4/rm32/sib    4/base/ESP  4/index/none              2/r32/EDX   4/disp8         .                 # copy *(ESP+4) to EDX
-58   # return n * factorial(n-1)
-59   0f af/multiply                  3/mod/direct    2/rm32/EDX    .           .             .           0/r32/EAX   .               .                 # multiply EDX (n) into EAX (factorial(n-1))
-60   # TODO: check for overflow
-61 $factorial:exit:
-62   c3/return
-63 
-64 # vim:ft=subx:nowrap:so=0
-
- - - -- cgit 1.4.1-2-gfad0