From 104e521c04d1a0cad9c68fb11e250e12ad8917ef Mon Sep 17 00:00:00 2001 From: Kartik Agaram Date: Wed, 17 Oct 2018 07:08:47 -0700 Subject: 4709 --- html/subx/055trace.subx.html | 373 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 373 insertions(+) create mode 100644 html/subx/055trace.subx.html (limited to 'html/subx/055trace.subx.html') diff --git a/html/subx/055trace.subx.html b/html/subx/055trace.subx.html new file mode 100644 index 00000000..16a7af2f --- /dev/null +++ b/html/subx/055trace.subx.html @@ -0,0 +1,373 @@ + + + + +Mu - subx/055trace.subx + + + + + + + + + + +
+  1 # helpers for emitting traces to a trace stream, and for tests to check the trace stream
+  2 #
+  3 # A trace stream looks like this:
+  4 #   read : int  # index that we've read until
+  5 #   write : int  # index at which writes go
+  6 #   data : (array byte)  # prefixed by length as usual
+  7 # In a real trace the data will be in a special segment set aside for the purpose.
+  8 #
+  9 # primitives for operating on traces:
+ 10 #   - initialize-trace-stream (update global variable)
+ 11 #   - trace: stream, string
+ 12 #   - die: stream (exit(1) if using real trace)
+ 13 #   - check-trace-contains: stream, string/line, string/message (scans only from stream's read pointer, prints message to stderr on failure, updates stream's read pointer)
+ 14 #   - rewind-reads: stream (resets read pointer)
+ 15 #   - scan-to-next-line: stream (advance read pointer past next newline)
+ 16 #
+ 17 # Traces are very fundamental, so many of the helpers we create here won't be
+ 18 # used elsewhere; we'll switch to more bounds-checked variants. But here we get
+ 19 # bounds-checking for free; we allocate a completely disjoint segment for trace
+ 20 # data, and overflowing it will generate a page fault.
+ 21 
+ 22 == data
+ 23 
+ 24 # We'll save the address of the trace segment here.
+ 25 Trace-stream:
+ 26   00 00 00 00
+ 27 
+ 28 # Fake trace-stream for tests.
+ 29 # Also illustrates the layout of the real trace-stream (segment).
+ 30 Test-trace-stream:
+ 31   # current write index
+ 32   00 00 00 00
+ 33   # current read index
+ 34   00 00 00 00
+ 35   # length (= 8)
+ 36   08 00 00 00
+ 37   # data
+ 38   00 00 00 00 00 00 00 00  # 8 bytes
+ 39 
+ 40 == code
+ 41 
+ 42 # instruction                     effective address                                                   operand     displacement    immediate
+ 43 # op          subop               mod             rm32          base        index         scale       r32
+ 44 # 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
+ 45 
+ 46 # main:  (manual test if this is the last file loaded)
+ 47   e8/call  run-tests/disp32  # 'run-tests' is a function created automatically by SubX. It calls all functions that start with 'test-'.
+ 48   # syscall(exit, Num-test-failures)
+ 49   8b/copy                         0/mod/indirect  5/rm32/.disp32            .             .           1/r32/EBX   Num-test-failures/disp32          # copy *Num-test-failures to EBX
+ 50   b8/copy-to-EAX  1/imm32
+ 51   cd/syscall  0x80/imm8
+ 52 
+ 53 # Allocate a new segment for the trace stream, initialize its length, and save its address to Trace-stream.
+ 54 # The Trace-stream segment will consist of variable-length lines separated by newlines (0x0a)
+ 55 initialize-trace-stream:
+ 56   # EAX = new-segment(0x1000)
+ 57     # push arg
+ 58   68/push  0x1000/imm32/N
+ 59     # call
+ 60   e8/call  new-segment/disp32
+ 61     # discard arg
+ 62   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+ 63   # copy EAX to *Trace-stream
+ 64   89/copy                         0/mod/indirect  5/rm32/.disp32            .             .           0/r32/EAX   Trace-stream/disp32               # copy EAX to *Trace-stream
+ 65   # Trace-stream.length = 0x1000/N - 12
+ 66   c7          0/copy              1/mod/*+disp8   0/rm32/EAX    .           .             .           .           8/disp8         0xff4/imm32       # copy 0xff4 to *(EAX+8)
+ 67   c3/return
+ 68 
+ 69 # Append to the given trace stream.
+ 70 trace:  # t : (address trace-stream), line : string
+ 71   # prolog
+ 72   55/push-EBP
+ 73   89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+ 74   # save registers
+ 75   50/push-EAX
+ 76   51/push-ECX
+ 77   52/push-EDX
+ 78   53/push-EBX
+ 79   56/push-ESI
+ 80   # EAX = t
+ 81   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none              0/r32/EAX   8/disp8         .                 # copy *(EBP+8) to EAX
+ 82   # EBX = line
+ 83   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none              3/r32/EBX   0xc/disp8       .                 # copy *(EBP+12) to EBX
+ 84   # append line to t.data from t.write
+ 85   #
+ 86   # pseudocode:
+ 87   #   destend = &t.data[t.length]
+ 88   #   oldw = t.write
+ 89   #   if line.length == 0 return
+ 90   #   t.write += line.length + 1  # for newline
+ 91   #   dest = &t.data[oldw]
+ 92   #   srcend = &line.data[line.length]
+ 93   #   src = &line.data[0]
+ 94   #   while true:
+ 95   #     if src >= srcend break
+ 96   #     if dest >= destend break  # for now silently ignore filled up trace buffer
+ 97   #     *dest = *src
+ 98   #     ++src
+ 99   #     ++dest
+100   #   if dest >= destend return
+101   #   *dest = 10/newline
+102   #
+103   # key registers to set up for the loop:
+104   #   EAX/dest, ECX/destend, EBX/src, ESI/srcend
+105   # we save EDX for byte operations (has to be one of the first 4 registers)
+106   #
+107   # register setup before the loop:
+108   #   EAX = *(EBP+8)    # t
+109   #   EBX = *(EBP+12)   # line
+110   #   ECX = *(EAX+8)    # t.length
+111   #   ECX = EAX+12+ECX  # destend = &t.data[t.length]
+112   #   ESI = *EAX        # oldw = t.write
+113   #   EDX = *EBX        # line.length
+114   #   *EAX = *EAX + EDX # update t.write  (allowed to go past t.length)
+115   #                     # do this here just because it's convenient
+116   #   ++ *EAX  # for the newline
+117   #   EAX = EAX+12+ESI  # dest = &t.data[oldw]
+118   #   ESI = EBX+4+EDX   # srcend = &line.data[line.length]
+119   #   EBX = EBX+4       # src = &line.data[0]
+120   #
+121   # EAX/t and EBX/line are already initialized
+122   # ECX = t.length
+123   8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EAX+8) to ECX
+124   # ECX/destend = &t.data[t.length]
+125   8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  1/index/ECX   .           1/r32/ECX   0xc/disp8       .                 # copy EAX+ECX+12 to ECX
+126   # ESI/oldw = t.write
+127   8b/copy                         0/mod/indirect  0/rm32/EAX    .           .             .           6/r32/ESI   .               .                 # copy *EAX to ESI
+128   # EDX = line.length
+129   8b/copy                         0/mod/indirect  3/rm32/EBX    .           .             .           2/r32/EDX   .               .                 # copy *EBX to EDX
+130   # if EDX == 0 return
+131   81          7/subop/compare     3/mod/direct    2/rm32/EDX    .           .             .           .           .               0/imm32           # compare EDX
+132   74/jump-if-equal  $trace:end/disp8
+133   # t.write += line.length
+134   01/add                          0/mod/indirect  0/rm32/EAX    .           .             .           2/r32/EDX   .               .                 # add EDX to *EAX
+135   # t.write++ (for the newline we'll append below)
+136   81          0/subop/add         0/mod/indirect  0/rm32/EAX    .           .             .           .           .               1/imm32           # add to *EAX
+137   # EAX/dest = &t.data[oldw]
+138   8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  6/index/ESI   .           0/r32/EAX   0xc/disp8       .                 # copy EAX+ESI+12 to EAX
+139   # ESI/srcend = &line.data[line.length]
+140   8d/copy-address                 1/mod/*+disp8   4/rm32/sib    3/base/EBX  2/index/EDX   .           6/r32/ESI   4/disp8         .                 # copy EBX+EDX+4 to ESI
+141   # EBX/src = &line.data[0]
+142   81          0/subop/add         3/mod/direct    3/rm32/EBX    .           .             .           .           .               4/imm32           # add to EBX
+143   # while (true)
+144 $trace:loop:
+145   # if EBX/src >= ESI/srcend break
+146   39/compare                      3/mod/direct    3/rm32/EBX    .           .             .           6/r32/ESI   .               .                 # compare EBX with ESI
+147   7d/jump-if-greater-or-equal  $trace:break/disp8
+148   # if EAX/dest >= ECX/destend break  (for now silently ignore filled up trace buffer)
+149   39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # compare EAX with ECX
+150   7d/jump-if-greater-or-equal  $trace:break/disp8
+151   # copy one byte
+152   8a/copy-byte                    0/mod/indirect  3/rm32/EBX    .           .             .           2/r32/DL    .               .                 # copy byte at *EBX to DL
+153   88/copy-byte                    0/mod/indirect  0/rm32/EAX    .           .             .           2/r32/DL    .               .                 # copy byte at DL to *EAX
+154   # updates
+155   40/increment-EAX
+156   43/increment-EBX
+157   eb/jump  $trace:loop/disp8
+158 $trace:break:
+159   # finally, append a newline
+160     # if EAX/dest >= ECX/destend return
+161   39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # compare EAX with ECX
+162   7d/jump-if-greater-or-equal  $trace:end/disp8
+163     # append
+164   ba/copy-to-EDX  0x0a/imm32
+165   88/copy-byte                    0/mod/indirect  0/rm32/EAX    .           .             .           2/r32/DL    .               .                 # copy byte at DL to *EAX
+166 $trace:end:
+167   # restore registers
+168   5e/pop-to-ESI
+169   5b/pop-to-EBX
+170   5a/pop-to-EDX
+171   59/pop-to-ECX
+172   58/pop-to-EAX
+173   # epilog
+174   89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+175   5d/pop-to-EBP
+176   c3/return
+177 
+178 clear-trace-stream:  # t : (address trace-stream)
+179   # prolog
+180   55/push-EBP
+181   89/copy                         3/mod/direct    5/rm32/EBP    .           .             .           4/r32/ESP   .               .                 # copy ESP to EBP
+182   # save registers
+183   50/push-EAX
+184   51/push-ECX
+185   # EAX = t
+186   8b/copy                         1/mod/*+disp8   4/rm32/sib    5/base/EBP  4/index/none              0/r32/EAX   8/disp8         .                 # copy *(EBP+8) to EAX
+187   # ECX = t.length
+188   8b/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           1/r32/ECX   8/disp8         .                 # copy *(EAX+8) to ECX
+189   # ECX = &t.data[t.length]
+190   8d/copy-address                 1/mod/*+disp8   4/rm32/sib    0/base/EAX  1/index/ECX   .           1/r32/ECX   0xc/disp8       .                 # copy EAX+ECX+12 to ECX
+191   # t.write = 0
+192   c7/copy                         0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # copy to *EAX
+193   # t.read = 0
+194   c7/copy                         1/mod/*+disp8   0/rm32/EAX    .           .             .           .           4/disp8         0/imm32           # copy to *(EAX+4)
+195   # EAX = t.data
+196   81          0/subop/add         3/mod/direct    0/rm32/EAX    .           .             .           .           .               0xc/imm32         # add to EAX
+197   # while (true)
+198 $clear-trace-stream:loop:
+199   # if EAX >= ECX break
+200   39/compare                      3/mod/direct    0/rm32/EAX    .           .             .           1/r32/ECX   .               .                 # compare EAX with ECX
+201   7d/jump-if-greater-or-equal  $clear-trace-stream:end/disp8
+202   # *EAX = 0
+203   c7/copy                         0/mod/direct    0/rm32/EAX    .           .             .           .           .               0/imm32           # copy to *EAX
+204   # EAX += 4
+205   81          0/subop/add         3/mod/direct    0/rm32/EAX    .           .             .           .           .               4/imm32           # add to EAX
+206   eb/jump  $clear-trace-stream:loop/disp8
+207 $clear-trace-stream:end:
+208   # restore registers
+209   59/pop-to-ECX
+210   58/pop-to-EAX
+211   # epilog
+212   89/copy                         3/mod/direct    4/rm32/ESP    .           .             .           5/r32/EBP   .               .                 # copy EBP to ESP
+213   5d/pop-to-EBP
+214   c3/return
+215 
+216 test-trace-single:
+217   # clear-trace-stream(Test-trace-stream)
+218     # push args
+219   68/push  Test-trace-stream/imm32
+220     # call
+221   e8/call  clear-trace-stream/disp32
+222     # discard args
+223   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+224   # trace(Test-trace-stream, "Ab")
+225     # push args
+226   68/push  "Ab"/imm32
+227   68/push  Test-trace-stream/imm32
+228     # call
+229   e8/call  trace/disp32
+230     # discard args
+231   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+232   # check-ints-equal(*Test-trace-stream.data, 41/A 62/b 0a/newline 00, msg)
+233     # push args
+234   68/push  "F - test-trace-single"/imm32
+235   68/push  0x0a6241/imm32/Ab-newline
+236     # push *Test-trace-stream.data
+237   b8/copy-to-EAX  Test-trace-stream/imm32
+238   ff          6/subop/push        1/mod/*+disp8   0/rm32/EAX    .           .             .           .           0xc/disp8       .                 # push *(EAX+12)
+239     # call
+240   e8/call  check-ints-equal/disp32
+241     # discard args
+242   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+243   # end
+244   c3/return
+245 
+246 test-trace-appends:
+247   # clear-trace-stream(Test-trace-stream)
+248     # push args
+249   68/push  Test-trace-stream/imm32
+250     # call
+251   e8/call  clear-trace-stream/disp32
+252     # discard args
+253   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+254   # trace(Test-trace-stream, "C")
+255     # push args
+256   68/push  "C"/imm32
+257   68/push  Test-trace-stream/imm32
+258     # call
+259   e8/call  trace/disp32
+260     # discard args
+261   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+262   # trace(Test-trace-stream, "D")
+263     # push args
+264   68/push  "D"/imm32
+265   68/push  Test-trace-stream/imm32
+266     # call
+267   e8/call  trace/disp32
+268     # discard args
+269   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+270   # check-ints-equal(*Test-trace-stream.data, 43/C 0a/newline 44/D 0a/newline, msg)
+271     # push args
+272   68/push  "F - test-trace-appends"/imm32
+273   68/push  0x0a440a43/imm32/C-newline-D-newline
+274     # push *Test-trace-stream.data
+275   b8/copy-to-EAX  Test-trace-stream/imm32
+276   ff          6/subop/push        1/mod/*+disp8   0/rm32/EAX    .           .             .           .           0xc/disp8       .                 # push *(EAX+12)
+277     # call
+278   e8/call  check-ints-equal/disp32
+279     # discard args
+280   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+281   # end
+282   c3/return
+283 
+284 test-trace-empty-line:
+285   # clear-trace-stream(Test-trace-stream)
+286     # push args
+287   68/push  Test-trace-stream/imm32
+288     # call
+289   e8/call  clear-trace-stream/disp32
+290     # discard args
+291   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               4/imm32           # add to ESP
+292   # trace(Test-trace-stream, "")
+293     # push args
+294   68/push  ""/imm32
+295   68/push  Test-trace-stream/imm32
+296     # call
+297   e8/call  trace/disp32
+298     # discard args
+299   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               8/imm32           # add to ESP
+300   # check-ints-equal(*Test-trace-stream.data, 0, msg)
+301     # push args
+302   68/push  "F - test-trace-empty-line"/imm32
+303   68/push  0/imm32
+304     # push *Test-trace-stream.data
+305   b8/copy-to-EAX  Test-trace-stream/imm32
+306   ff          6/subop/push        1/mod/*+disp8   0/rm32/EAX    .           .             .           .           0xc/disp8       .                 # push *(EAX+12)
+307     # call
+308   e8/call  check-ints-equal/disp32
+309     # discard args
+310   81          0/subop/add         3/mod/direct    4/rm32/ESP    .           .             .           .           .               0xc/imm32         # add to ESP
+311   # end
+312   c3/return
+313 
+314 # vim:nowrap:textwidth=0
+
+ + + -- cgit 1.4.1-2-gfad0