diff options
| -rw-r--r-- | subx/ex7.subx | 26 |
1 files changed, 0 insertions, 26 deletions
diff --git a/subx/ex7.subx b/subx/ex7.subx index e312edbe..78b362db 100644 --- a/subx/ex7.subx +++ b/subx/ex7.subx @@ -14,76 +14,50 @@ # main: # prepare to make a call -# 54 55/push . . . . . . . . # push EBP -# 55 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP -# 57 # factorial(5) 68/push . . . . . . . 5/imm32 # push 5 -# 5c e8/call . . . . . . factorial/disp32 -# 61 # discard arg 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 -# 64 5d/pop . . . . . . . . # pop to EBP # exit(EAX) -# 65 89/copy 3/mod/direct 3/rm32/EBX . . . 0/r32/EAX . . # copy EAX to EBX -# 67 b8/copy . . . . . . . 1/imm32 # copy 1 to EAX -# 6c 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 -# 72 # initialize EAX to 1 (base case) 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 -# 7d 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 -# 81 81 5/subop/subtract 3/mod/direct 3/rm32/EBX . . . . . 1/imm32 # subtract 1 from EBX -# 87 # prepare call 55/push . . . . . . . . # push EBP -# 88 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP # EAX: factorial(n-1) -# 8a 53/push . . . . . . . . # push EBX -# 8b e8/call . . . . . . factorial/disp32 -# 90 # discard arg 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 -# 93 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 -# 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)) # TODO: check for overflow -# 9b factorial:exit: c3/return |