From 634b162a980f72ae1d822e593f7975fa8e1ad3e8 Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Thu, 3 Jan 2019 17:02:17 -0800 Subject: 4901 --- subx/052kernel_string_equal.subx | 260 --------------------------------------- 1 file changed, 260 deletions(-) delete mode 100644 subx/052kernel_string_equal.subx (limited to 'subx/052kernel_string_equal.subx') diff --git a/subx/052kernel_string_equal.subx b/subx/052kernel_string_equal.subx deleted file mode 100644 index 67e9695e..00000000 --- a/subx/052kernel_string_equal.subx +++ /dev/null @@ -1,260 +0,0 @@ -# Checking null-terminated ascii strings. -# -# By default we create strings with a 4-byte length prefix rather than a null suffix. -# However we still need null-prefixed strings when interacting with the Linux -# kernel in a few places. This layer implements a function for comparing -# a null-terminated 'kernel string' with a length-prefixed 'SubX string'. -# -# To run (from the subx directory): -# $ ./subx translate 05[0-2]*.subx -o /tmp/tmp52 -# $ ./subx run /tmp/tmp52 # runs a series of tests -# ...... # all tests pass -# -# (We can't yet run the tests when given a "test" commandline argument, -# because checking for it would require the function being tested! Breakage -# would cause tests to not run, rather than to fail as we'd like.) - -== code -# instruction effective address register displacement immediate -# . op subop mod rm32 base index scale r32 -# . 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 - -# main: - e8/call run-tests/disp32 # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'. - # syscall(exit, Num-test-failures) - 8b/copy 0/mod/indirect 5/rm32/.disp32 . . 3/r32/EBX Num-test-failures/disp32 # copy *Num-test-failures to EBX - b8/copy-to-EAX 1/imm32/exit - cd/syscall 0x80/imm8 - -# 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 - # . prolog - 55/push-EBP - 89/copy 3/mod/direct 5/rm32/EBP . . . 4/r32/ESP . . # copy ESP to EBP - # . save registers - 51/push-ECX - 52/push-EDX - 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 - 8b/copy 1/mod/*+disp8 5/rm32/EBP . . . 7/r32/EDI 8/disp8 . # copy *(EBP+8) to EDI - # initialize benchmark length n into EDX - 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 - 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 - 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 - 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 - # 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 - 41/inc-ECX - 46/inc-ESI - 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 - 8a/copy 0/mod/indirect 7/rm32/EDI . . . 0/r32/EAX . . # copy byte at *EDI to lower byte of EAX - 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 - eb/jump $kernel-string-equal:end/disp8 - # return false -$kernel-string-equal:false: - b8/copy-to-EAX 0/imm32 -$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 - # . epilog - 89/copy 3/mod/direct 4/rm32/ESP . . . 5/r32/EBP . . # copy EBP to ESP - 5d/pop-to-EBP - c3/return - -# - tests - -test-compare-null-kernel-string-with-empty-array: - # 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 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # check-ints-equal(EAX, 1, msg) - # . . push args - 68/push "F - test-compare-null-kernel-string-with-empty-array"/imm32 - 68/push 1/imm32/true - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-null-kernel-string-with-non-empty-array: - # 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 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 8/imm32 # add to ESP - # check-ints-equal(EAX, 0, msg) - # . . push args - 68/push "F - test-compare-null-kernel-string-with-non-empty-array"/imm32 - 68/push 0/imm32/false - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-kernel-string-with-equal-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Abc") - # . . push args - 68/push "Abc"/imm32 - 68/push Abc-kernel-string/imm32 - # . . call - 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) - # . . push args - 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 - 68/push 1/imm32/true - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-kernel-string-with-inequal-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Adc") - # . . push args - 68/push "Adc"/imm32 - 68/push Abc-kernel-string/imm32 - # . . call - 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) - # . . push args - 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 - 68/push 0/imm32/false - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-kernel-string-with-empty-array: - # EAX = kernel-string-equal(Abc-kernel-string, "") - # . . push args - 68/push ""/imm32 - 68/push Abc-kernel-string/imm32 - # . . call - 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) - # . . push args - 68/push "F - test-compare-kernel-string-with-equal-array"/imm32 - 68/push 0/imm32/false - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-kernel-string-with-shorter-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Ab") - # . . push args - 68/push "Ab"/imm32 - 68/push Abc-kernel-string/imm32 - # . . call - 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) - # . . push args - 68/push "F - test-compare-kernel-string-with-shorter-array"/imm32 - 68/push 0/imm32/false - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -test-compare-kernel-string-with-longer-array: - # EAX = kernel-string-equal(Abc-kernel-string, "Abcd") - # . . push args - 68/push "Abcd"/imm32 - 68/push Abc-kernel-string/imm32 - # . . call - 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) - # . . push args - 68/push "F - test-compare-kernel-string-with-longer-array"/imm32 - 68/push 0/imm32/false - 50/push-EAX - # . . call - e8/call check-ints-equal/disp32 - # . . discard args - 81 0/subop/add 3/mod/direct 4/rm32/ESP . . . . . 0xc/imm32 # add to ESP - c3/return - -== data - -Null-kernel-string: - 00/null -Abc-kernel-string: - 41/A 62/b 63/c 00/null - -# . . vim:nowrap:textwidth=0 -- cgit 1.4.1-2-gfad0