diff options
Diffstat (limited to 'subx/examples/ex11.subx')
| -rw-r--r-- | subx/examples/ex11.subx | 135 |
1 files changed, 71 insertions, 64 deletions
diff --git a/subx/examples/ex11.subx b/subx/examples/ex11.subx index 7fb83eb6..49e0c753 100644 --- a/subx/examples/ex11.subx +++ b/subx/examples/ex11.subx @@ -28,7 +28,28 @@ # compare a null-terminated ascii string with a more idiomatic length-prefixed byte array # reason for the name: the only place we should have null-terminated ascii strings is from commandline args -kernel-string-equal: # s : null-terminated ascii string, benchmark : length-prefixed ascii string -> EAX : boolean +kernel-string-equal?: # s : null-terminated ascii string, benchmark : length-prefixed ascii string -> EAX : boolean + # pseudocode: + # n = benchmark->length + # s1 = s + # s2 = benchmark->data + # i = 0 + # while (i < n) + # c1 = *s1 + # c2 = *s2 + # if (c1 == 0) return false + # if (c1 != c2) return false + # ++s1, ++s2, ++i + # return *s1 == 0 + # + # registers: + # i: ECX + # n: EDX + # s1: EDI + # s2: ESI + # c1: EAX + # c2: EBX + # # . prolog 55/push-EBP 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP @@ -38,72 +59,57 @@ kernel-string-equal: # s : null-terminated ascii string, benchmark : length-pre 53/push-EBX 56/push-ESI 57/push-EDI - - # pseudocode: - # initialize n = b->length - # initialize s1 = s - # initialize s2 = b->data - # i = 0 - # for (i = 0; i < n; ++n) - # c1 = *s1 - # c2 = *s2 - # if c1 == 0 - # return false - # if c1 != c2 - # return false - # return *s1 == 0 - # initialize s into EDI + # s1/EDI = s 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI - # initialize benchmark length n into EDX + # n/EDX = benchmark->length 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 2/r32/EDX 0xc/disp8 . # copy *(EBP+12) to EDX 8b/copy 0/mod/indirect 2/rm32/EDX . . . 2/r32/EDX . . # copy *EDX to EDX - # initialize benchmark data into ESI + # s2/ESI = benchmark->data 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 6/r32/ESI 0xc/disp8 . # copy *(EBP+12) to ESI 81 0/subop/add 3/mod/direct 6/rm32/ESI . . . . . 4/imm32 # add to ESI - # initialize loop counter i into ECX + # i/ECX = c1/EAX = c2/EBX = 0 b9/copy-to-ECX 0/imm32/exit - # while (i/ECX < n/EDX) -$kernel-string-equal:loop: - 39/compare 3/mod/direct 1/rm32/ECX . . . 2/r32/EDX . . # compare ECX with EDX - 74/jump-if-equal $kernel-string-equal:break/disp8 - # c1/EAX, c2/EBX = *s, *benchmark b8/copy-to-EAX 0/imm32 - 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX bb/copy-to-EBX 0/imm32 +$kernel-string-equal?:loop: + # if (i >= n) break + 39/compare 3/mod/direct 1/rm32/ECX . . . 2/r32/EDX . . # compare ECX with EDX + 7d/jump-if-greater-or-equal $kernel-string-equal?:break/disp8 + # c1 = *s1 + 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX + # c2 = *s2 8a/copy 0/mod/indirect 6/rm32/ESI . . . 3/r32/EBX . . # copy byte at *ESI to lower byte of EBX # if (c1 == 0) return false 3d/compare-EAX 0/imm32 - 74/jump-if-equal $kernel-string-equal:false/disp8 + 74/jump-if-equal $kernel-string-equal?:false/disp8 # if (c1 != c2) return false 39/compare 3/mod/direct 0/rm32/EAX . . . 3/r32/EBX . . # compare EAX with EBX - 75/jump-if-not-equal $kernel-string-equal:false/disp8 - # ++s1, ++s2, ++i + 75/jump-if-not-equal $kernel-string-equal?:false/disp8 + # ++i 41/inc-ECX - 46/inc-ESI + # ++s1 47/inc-EDI - # end while - eb/jump $kernel-string-equal:loop/disp8 -$kernel-string-equal:break: - # if (*s/EDI == 0) return true - b8/copy-to-EAX 0/imm32 + # ++s2 + 46/inc-ESI + eb/jump $kernel-string-equal?:loop/disp8 +$kernel-string-equal?:break: + # return *s1 == 0 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX - 81 7/subop/compare 3/mod/direct 0/rm32/EAX . . . . . 0/imm32 # compare EAX - 75/jump-if-not-equal $kernel-string-equal:false/disp8 + 3d/compare-EAX 0/imm32 + 75/jump-if-not-equal $kernel-string-equal?:false/disp8 +$kernel-string-equal?:true: b8/copy-to-EAX 1/imm32 -$kernel-string-equal:true: - eb/jump $kernel-string-equal:end/disp8 - # return false -$kernel-string-equal:false: + eb/jump $kernel-string-equal?:end/disp8 +$kernel-string-equal?:false: b8/copy-to-EAX 0/imm32 - -$kernel-string-equal:end: +$kernel-string-equal?:end: # . restore registers 5f/pop-to-EDI 5e/pop-to-ESI 5b/pop-to-EBX 5a/pop-to-EDX 59/pop-to-ECX - # end + # . epilog 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP 5d/pop-to-EBP c3/return @@ -111,12 +117,12 @@ $kernel-string-equal:end: # - tests test-compare-null-kernel-string-with-empty-array: - # EAX = kernel-string-equal(Null-kernel-string, "") + # EAX = kernel-string-equal?(Null-kernel-string, "") # . . push args 68/push ""/imm32 68/push Null-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 1, msg) @@ -131,12 +137,12 @@ test-compare-null-kernel-string-with-empty-array: c3/return test-compare-null-kernel-string-with-non-empty-array: - # EAX = kernel-string-equal(Null-kernel-string, "Abc") + # EAX = kernel-string-equal?(Null-kernel-string, "Abc") # . . push args 68/push "Abc"/imm32 68/push Null-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 0, msg) @@ -151,12 +157,12 @@ test-compare-null-kernel-string-with-non-empty-array: c3/return test-compare-kernel-string-with-equal-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Abc") + # EAX = kernel-string-equal?(_test-Abc-kernel-string, "Abc") # . . push args 68/push "Abc"/imm32 - 68/push Abc-kernel-string/imm32 + 68/push _test-Abc-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 1, msg) @@ -171,12 +177,12 @@ test-compare-kernel-string-with-equal-array: c3/return test-compare-kernel-string-with-inequal-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Adc") + # EAX = kernel-string-equal?(_test-Abc-kernel-string, "Adc") # . . push args 68/push "Adc"/imm32 - 68/push Abc-kernel-string/imm32 + 68/push _test-Abc-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 0, msg) @@ -191,12 +197,12 @@ test-compare-kernel-string-with-inequal-array: c3/return test-compare-kernel-string-with-empty-array: - # EAX = kernel-string-equal(Abc-kernel-string, "") + # EAX = kernel-string-equal?(_test-Abc-kernel-string, "") # . . push args 68/push ""/imm32 - 68/push Abc-kernel-string/imm32 + 68/push _test-Abc-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 0, msg) @@ -211,12 +217,12 @@ test-compare-kernel-string-with-empty-array: c3/return test-compare-kernel-string-with-shorter-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Ab") + # EAX = kernel-string-equal?(_test-Abc-kernel-string, "Ab") # . . push args 68/push "Ab"/imm32 - 68/push Abc-kernel-string/imm32 + 68/push _test-Abc-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 0, msg) @@ -231,12 +237,12 @@ test-compare-kernel-string-with-shorter-array: c3/return test-compare-kernel-string-with-longer-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Abcd") + # EAX = kernel-string-equal?(_test-Abc-kernel-string, "Abcd") # . . push args 68/push "Abcd"/imm32 - 68/push Abc-kernel-string/imm32 + 68/push _test-Abc-kernel-string/imm32 # . . call - e8/call kernel-string-equal/disp32 + e8/call kernel-string-equal?/disp32 # . . discard args 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP # check-ints-equal(EAX, 0, msg) @@ -263,7 +269,7 @@ check-ints-equal: # (a : int, b : int, msg : (address array byte)) -> boolean # load args into EAX, EBX and ECX 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 0/r32/EAX 8/disp8 . # copy *(EBP+8) to EAX 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 3/r32/EBX 0xc/disp8 . # copy *(EBP+12) to EBX - # if EAX == b/EBX print('.') and return + # if (EAX == b/EBX) print('.') and return 39/compare 3/mod/direct 0/rm32/EAX . . . 3/r32/EBX . . # compare EAX and EBX 75/jump-if-unequal $check-ints-equal:else/disp8 # . write-stderr('.') @@ -344,7 +350,8 @@ Newline: # for kernel-string-equal tests Null-kernel-string: 00/null -Abc-kernel-string: + +_test-Abc-kernel-string: 41/A 62/b 63/c 00/null # . . vim:nowrap:textwidth=0 |