diff options
| -rwxr-xr-x | subx/apps/factorial | bin | 1200 -> 1208 bytes | |||
| -rw-r--r-- | subx/apps/factorial.subx | 14 |
2 files changed, 11 insertions, 3 deletions
diff --git a/subx/apps/factorial b/subx/apps/factorial index 00904aee..4f93fe32 100755 --- a/subx/apps/factorial +++ b/subx/apps/factorial Binary files differdiff --git a/subx/apps/factorial.subx b/subx/apps/factorial.subx index 3dd8bdaa..b74fba89 100644 --- a/subx/apps/factorial.subx +++ b/subx/apps/factorial.subx @@ -55,13 +55,17 @@ $main_exit: # factorial(n) factorial: + # prolog + 55/push-EBP + 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP + 53/push-EBX # initialize EAX to 1 (base case) b8/copy . . . . . . . 1/imm32 # copy 1 to EAX # if (n <= 1) jump exit - 81 7/subop/compare 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none . . 4/disp8 1/imm32 # compare *(ESP+4) with 1 + 81 7/subop/compare 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none . . 8/disp8 1/imm32 # compare *(EBP+8) with 1 7e/jump-if-<= $factorial:exit/disp8 # EBX: n-1 - 8b/copy 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 3/r32/EBX 4/disp8 . # copy *(ESP+4) to EBX + 8b/copy 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none 3/r32/EBX 8/disp8 . # copy *(EBP+8) to EBX 81 5/subop/subtract 3/mod/direct 3/rm32/EBX . . . . . 1/imm32 # subtract 1 from EBX # EAX: factorial(n-1) 53/push-EBX @@ -69,9 +73,13 @@ factorial: # discard arg 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 4/imm32 # add 4 to ESP # return n * factorial(n-1) - f7 4/subop/multiply 1/mod/*+disp8 4/rm32/sib 4/base/ESP 4/index/none 4/disp8 . # multiply *(ESP+4) (n) into EAX (factorial(n-1)) + f7 4/subop/multiply 1/mod/*+disp8 4/rm32/sib 5/base/EBP 4/index/none 8/disp8 . # multiply *(EBP+8) into EAX # TODO: check for overflow $factorial:exit: + # epilog + 5b/pop-EBX + 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP + 5d/pop-to-EBP c3/return test_factorial: |