diff options
Diffstat (limited to 'linux/factorial2.subx')
| -rw-r--r-- | linux/factorial2.subx | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/linux/factorial2.subx b/linux/factorial2.subx new file mode 100644 index 00000000..22c3d5be --- /dev/null +++ b/linux/factorial2.subx @@ -0,0 +1,122 @@ +## compute the factorial of 5, and return the result in the exit code +# +# Uses syntax sugar for: +# rm32 operands +# +# To run: +# $ ./translate_subx init.linux [01]*.subx apps/factorial.subx -o apps/factorial +# $ ./bootstrap run apps/factorial +# Expected result: +# $ echo $? +# 120 +# +# You can also run the automated test suite: +# $ ./bootstrap run apps/factorial test +# Expected output: +# ........ +# Every '.' indicates a passing test. Failing tests get a 'F'. +# +# Compare apps/factorial.subx + +== code + +factorial: # n: int -> _/eax: int + # . prologue + 55/push-ebp + 89/<- %ebp 4/r32/esp + # save registers + 51/push-ecx + # if (n <= 1) return 1 + b8/copy-to-eax 1/imm32 + 81 7/subop/compare *(ebp+8) 1/imm32 + 7e/jump-if-<= $factorial:end/disp8 + # n > 1; return n * factorial(n-1) + 8b/-> *(ebp+8) 1/r32/ecx + 49/decrement-ecx + # var tmp/eax: int = factorial(n-1) + # . . push args + 51/push-ecx + # . . call + e8/call factorial/disp32 + # . . discard args + 81 0/subop/add %esp 4/imm32 + # return n * tmp + f7 4/subop/multiply-into-eax *(ebp+8) + # TODO: check for overflow +$factorial:end: + # restore registers + 59/pop-to-ecx + # . epilogue + 89/<- %esp 5/r32/ebp + 5d/pop-to-ebp + c3/return + +test-factorial: + # factorial(5) + # . . push args + 68/push 5/imm32 + # . . call + e8/call factorial/disp32 + # . . discard args + 81 0/subop/add %esp 4/imm32 + # check-ints-equal(eax, 120, msg) + # . . push args + 68/push "F - test-factorial"/imm32 + 68/push 0x78/imm32/expected-120 + 50/push-eax + # . . call + e8/call check-ints-equal/disp32 + # . . discard args + 81 0/subop/add %esp 0xc/imm32 + # end + c3/return + +Entry: # run tests if necessary, compute `factorial(5)` if not + # . prologue + 89/<- %ebp 4/r32/esp + + # initialize heap (needed by tests elsewhere) + # . Heap = new-segment(Heap-size) + # . . push args + 68/push Heap/imm32 + ff 6/subop/push *Heap-size + # . . call + e8/call new-segment/disp32 + # . . discard args + 81 0/subop/add %esp 8/imm32 + + # if (argc <= 1) return factorial(5) + 81 7/subop/compare *ebp 1/imm32 + 7f/jump-if-> $main:run-tests/disp8 + # . . push args + 68/push 5/imm32 + # . . call + e8/call factorial/disp32 + # . . discard args + 81 0/subop/add %esp 4/imm32 + # . + 89/<- %ebx 0/r32/eax + eb/jump $main:end/disp8 +$main:run-tests: + # otherwise if first arg is "test", then return run_tests() + # if (!kernel-string-equal?(argv[1], "test")) goto do-nothing + # . eax = kernel-string-equal?(argv[1], "test") + # . . push args + 68/push "test"/imm32 + ff 6/subop/push *(ebp+8) + # . . call + e8/call kernel-string-equal?/disp32 + # . . discard args + 81 0/subop/add %esp 8/imm32 + # . if (eax == false) goto do-nothing + 3d/compare-eax-and 0/imm32/false + 74/jump-if-= $main:do-nothing/disp8 + # run-tests() + e8/call run-tests/disp32 + # exit(*Num-test-failures) + 8b/-> *Num-test-failures 3/r32/ebx + eb/jump $main:end/disp8 +$main:do-nothing: + bb/copy-to-ebx 0/imm32 +$main:end: + e8/call syscall_exit/disp32 |