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authorKartik Agaram <vc@akkartik.com>2019-01-03 17:02:17 -0800
committerKartik Agaram <vc@akkartik.com>2019-01-03 17:02:17 -0800
commit634b162a980f72ae1d822e593f7975fa8e1ad3e8 (patch)
tree9f3cd2b8c3a6445c36268392fc8ef2bf820401d6 /subx/052kernel_string_equal.subx
parent1ffb27a045c63217336e2c926058360e9521afc9 (diff)
downloadmu-634b162a980f72ae1d822e593f7975fa8e1ad3e8.tar.gz
4901
Diffstat (limited to 'subx/052kernel_string_equal.subx')
-rw-r--r--subx/052kernel_string_equal.subx260
1 files changed, 0 insertions, 260 deletions
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